dyson slim dc18

Dyson Slim DC18 Upright – Undercarriage Repair


This post gives a detailed description, with photos and reference to a Parts Diagram, of how to replace a Dyson Slim DC18 Undercarriage. The Undercarriage would require changing if part of it broke since parts cannot be obtained individually. I changed mine when the Air Input Changeover Valve Actuator broke.

“Since I first published this article, in February 2013, I have had plenty of feedback from readers and I have gleaned information from statistical data which has encouraged me to improve it. So if you came here soon after I published it you should find better information now. You will also find some photos of repairs carried out by readers of this post in Step 10.” — Helpful Colin

Diagrammatic Breakdown of a Dyson Slim DC18

Here is a very clear diagrammatic breakdown of: The Parts of a DC18. This site, Parts Warehouse, may also be a place where readers in the USA find it convenient to buy replacement parts.

NOTE: As a consequence of finding the parts diagram above, I have renamed parts in my description to conform with it.

Clarification of Dyson/Parts-Warehouse Part’s Names

In The parts of a DC18 there are items listed whose names are, in my opinion, not correct. So I have listed below what those part names really refer to:

  • Pre Filter – refers to – Pre Motor Filter,
  • Pre Filter Assy (Assembly) – refers to – Pre Motor Filter Assy (Assembly).
  • Post Filter – refers to – Post Motor Filter,
  • Post Filter Assy (Assembly) – refers to – Post Motor Filter Assy (Assembly),
  • HEPA Post Filter Assy (Assembly) – refers to – HEPA Post Motor Filter Assy (Assembly),
  • Post Filter Cage Assy (Assembly) – refers to – Post Motor Filter Cage Assy (Assembly),
  • Post Filter Cover – refers to – Post Motor Filter Cover.

I will continue to refer to the items above by the Dyson/Parts Warehouse names to avoid confusion.

My Dyson Slim DC18 Undercarriage Problem

I wrote this article after I had a problem with my Dyson Slim DC18 where the rotating Air Input Changeover Valve in the Undercarriage didn’t work. Its purpose is to change the airflow from the Cleaner Head Assembly to the Hose Assembly when the DC18 body is lifted and locked into the upright position. A piece of plastic on a moving part of the undercarriage which should engage and operate the Changeover Valve mechanism had broken off. On investigation I found it necessary to replace the entire undercarriage, to fix it, because I could not buy an individual part.


I obtained the new undercarriage for my Dyson Slim DC18 from espares a UK online parts store. (I’m sure parts can be obtained from other stores worldwide.) They asked me for a review. You can find it here under Reviews of Dyson Undercarriage Assembly for DC18 dated 10 February 2013.

“Across the pond (in the USA) you can get parts from ereplacementparts.com. They have a nice site with exploded parts views for many products.” — Andrew Pardoe (25/08/2016)

The Dyson Slim DC18 Undercarriage

For those who don’t know what part is the undercarriage this is it:

Pic. 1. The Dyson Slim DC18 Undercarriage
The Dyson Slim DC18 Undercarriage
Pic. 1. The Dyson Slim DC18 Undercarriage

The Dyson Slim DC18 undercarriage is separate from the body and does not include the Barrel Wheel and Yoke Assemblies. The one above is taken from my Dyson Slim DC18 and has a broken Changeover Valve Actuator which would otherwise operate the Changeover Valve when the Dyson Slim DC18 is raised or lowered.

Removing A Dyson Slim DC18 Undercarriage

The main components of a Dyson Slim DC18 are:

  • Main Body (Duct Assembly and its parts).
  • Rotating Brush Head or Cleaner Head Assembly.
  • Undercarriage.
  • Barrel Wheel and Yoke Assemblies.
  • Cyclone and Bin Assemblies.

The tools required to work on a Dyson Slim DC18 undercarriage are:

  • 3mm Flat Screwdriver (to remove e-clips).
  • 6mm Flat Screwdriver (to prise open the electrical socket).
  • Pliers (to replace e-clips).
  • Hexagonal Bit Driver for the following bits.
  • TX-STAR security bit T8 (for one screw).
  • TX-STAR security bit T15 (for all but one screw).

Some of the tools above were obtained from Maplin. Unfortunately that store has closed so I cannot link to it. – HC

Most DIY and hardware stores sell similar tools.

UK examples:

The component parts of a dismantled Dyson Slim DC18 with the tools for working on it:

Pic. 2. Dyson Slim DC18 Parts & tools used for dismantling it
Dyson Slim DC18 Parts with tools used for dismantling it.
Pic. 2. Dyson Slim DC18 Parts & tools used for dismantling it. Select the image to enlarge it.

NOTE: A new undercarriage doesn’t include the Barrel Wheel and Yoke Assemblies.

The Barrel Wheel and Yoke Assemblies include:

  • Barrel Wheel.
  • Axle.
  • 2 × e-clips.
  • Cleaner Head Assembly mounting point with Pipe Seal.
  • 2 × Outer Wheel Hubs.
e-clip circlip

What Is An e-clip?

This is what an e-clip looks like for those who are uncertain. They usually clip into a groove on an axle or spindle. Their presence then stops a close fitting object such as a wheel from moving along the axle or spindle.

Dyson Slim DC18 Undercarriage 15 Step Replacement Process

Start by removing the Cleaner Head Assembly and disconnecting the flexible hose at the back as per user instructions. Then follow the 15 instruction steps below numbered 1 to 15.

NOTE: Steps 1 to 7 are disassembly instructions and 8 to 15 are reassembly instructions.


1. Uncouple the Yoke & Undercarriage.

Before removing the Undercarriage the Yoke Assembly has to be uncoupled from it by withdrawing the Axle that passes through the centre of the Barrel Wheel. The Axle passes through the Yoke Assembly, the Undercarriage and the Barrel Wheel and holds the three components together.

To access the ends of the Barrel Wheel Axle pull off the Outer Wheel Hubs. There are two ways to do this:

  1. curl the tips of your fingers around the edge and pulling them off. (Some force is required but the plastic seems to be strong enough.)
  2. release the cleaner from the upright position, using the foot peddle, and lay it down on the floor as in the picture below to expose the lugs on the Outer Wheel Hubs (as described in the comment submitted by Rachel Hall). You can then use a long screwdriver to assist in pushing the lugs through the hole in which they are located.
Pic. 3. Lugs of the Outer Wheel Hub exposed
Dyson Slim DC18 showing the lugs of the Outer Wheel Hub
Pic. 3. Lugs of the Outer Wheel Hub exposed. (The Cleaner Head Assembly is still attached in this photo.)

Once one is removed you will see more clearly how the four springy plastic lugs in the centre of each Outer Wheel Hub holds it in place. They are clicked into a central hole.

The Outer Wheel Hubs can rotate but only come into contact with the floor when the cleaner is leaned over to the side. This happens when the cleaner is leaned over to go along a curved path.

When the Yoke Assembly is detached it becomes easy to access the four screws which hold the Undercarriage to the Main Body Duct Assembly at the front. There are two other screws which are accessed from the back. DO NOT UNDO ANY OF THESE SCREWS YET. Wait until instructions 5 and 6.

2. Undo the T15 screw and remove the Swivel Cover.

The cover holds the Female Connector Housing Assembly (electric socket for the Cleaner Head Assembly) in place. Winkle out the socket and split the black plastic of the socket into two pieces (they are not glued but clip together). Only the cable and pins in the socket will pass through the holes in the undercarriage, so take the electrical pins out of the black plastic cover and observe carefully how this socket is assembled.

“Take a picture to show the wire colours so you can put it together again and maintain electrical safety.” — Andrew Pardoe (25th August 2016)

You may need a 6mm flat screwdriver to prise the clips open on the socket cover. Be careful. Excess strain on these clips may snap them off.

Pic.4. Cleaner Head Swivel & Socket Housing with cover
Dyson Slim DC18 Cleaner Head Swivel and Socket Housing with cover in place.
Pic.4. Cleaner Head Swivel and Socket Housing with cover in place.
Pic. 5. Cleaner Head Swivel and Socket Housing without cover
Dyson Slim DC18 Cleaner Head Swivel and Socket Housing with cover removed.
Pic. 5. Cleaner Head Swivel and Socket Housing with cover removed.

NOTE: There is no earth wire going to the Cleaner Head because there are no metal parts with which the user can come into contact. The principle of Double Insulation Class II keeps users safe from the live electrical supply. Also the supply is AC (Alternating Current) which has no polarity. So I cannot see that it matters which way around the live and neutral wires are placed in the Cleaner Head Socket. The issue is more one of mechanical convenience. By that I mean the wires are short, tight and conveniently assembled by the manufacturer and I suggest it is best to put them back in the same way so that they don’t become damaged.

For those who feel there is a safety issue with the polarity of the wires just make a note of which way around the colours are, or take a photograph, before dismantling the socket. In the UK and EU the wire’s colours are blue and brown, and in the USA I am informed by Ellem Kay (see comments dated 9th July 2017) that blue=white and brown=black. Thanks Ellem.

3. Remove the Cleaning Head Assembly Pipe Seal which prevents the pipe dropping back through the socket.

Pull the Pipe Seal out of the socket it sits in and stretch the seal so that it can be pulled over the ridges on the end of the flexible pipe. There are two ridges on the pipe and two matching grooves in the seal into which they engage. The seal sits in the socket and is prevented from rotating in the socket by teeth similar to those on a gear wheel. There are teeth on the seal and teeth on the edge of the socket which engage with each other. See the picture below to understand how these parts fit together.

Pic. 6. Four pictures of the Rotary Brush Assembly Pipe & Seal
Four pictures of the Dyson Slim DC18 Rotary Brush Assembly Pipe and Seal.
Pic. 6. Four pictures of the Rotary Brush Assembly Pipe and Seal.

4. Remove the Micro-switch which senses when the cleaner is locked in the upright position.

This micro-switch is on one side of the undercarriage under a cover.

NOTE: Before removing the Micro-switch you may wish to go to Step 7 and remove the Barrel Wheel and Yoke Assemblies to gain better access to this switch. Afterwards return here.

Remove the cover by unscrewing the screw with the T8 bit and then pull the switch out of the housing together with its wires.

A rotating black plastic cam (part of the Micro-switch Cam Assembly) moves under the lever of the switch to operate it when the DC18 is stood in the upright position. Examine this closely. The cam is spring-loaded and in my new undercarriage the spring was not inserted correctly and so was not applying a force to rotate the cam and push it up under the micro-switch lever.

Consequently after reassembly the upright position wasn’t correctly detected. I had to dismantle part of the Undercarriage to fix the problem. The spring should rotate the cam to push on the switch lever. So the cam should not be floppy. Check it with the switch removed. The cam should want to move into the visible position under the action of the spring which is out of site.

Pic. 7. Upright Position Detection Micro-switch
Dyson Slim DC18 Upright Position Detection Micro-switch.
Pic. 7. Upright Position Detection Micro-switch.

5. Remove the four screws holding the Undercarriage to the bottom of the DC18 body (Duct Assembly) at the front using the T15 bit.

Pic. 8. Screws Holding the Undercarriage to the Body
Screws Holding the Dyson Slim DC18 Undercarriage to the Body.
Pic. 8. Screws Holding the Undercarriage to the Body.

6. Remove two similar screws that hold the undercarriage bracket to the rear of the DC18 body (Duct Assembly) near the flexible hose connection port.

Pic. 9. Undercarriage Fixing Bracket and Hand Tool Hose Connection Port at the back of the DC18
Undercarriage Fixing Bracket and Hand Tool Hose Connection Port at the back of the Dyson Slim DC18.
Pic. 9. Undercarriage Fixing Bracket and Hand Tool Hose Connection Port at the back of the DC18.

7. Remove the Barrel Wheel.

Do this by prising off the e-clip on one end of the Axle. Do it by inserting a small (3mm) flat screwdriver in the gap between the e-clip and Axle and twisting. This stretches the e-clip, against its springiness, to a larger diameter so it will come off the Axle. Note how the e-clip sits in a groove on the Axle.

The Axle can be pulled out from the far side, the Barrel Wheel will drop free and the Yoke Assembly will come away from the undercarriage.

The flexible connecting pipe is part of the Undercarriage so they are replaced together. Effectively the Undercarriage is in two parts the Undercarriage and the Yoke but only the Undercarriage with the small wheels and red foot pedal attached is replaced here.

Ease the wires and Micro-switch out of the holes in the undercarriage taking careful note of how to re thread them.

Return to Step 4 if you were at that step.

Pic. 10. e-clip Removal
Dyson Slim DC18 e-clip Removal.
Pic. 10. e-clip Removal


8. Commence reassembly using the new Undercarriage.

Carefully thread the Micro-switch and wires back through orifices in the plastic. During reassembly it’s difficult to thread the cable back through the small orifice in the undercarriage shown below:

Pic. 11. Location of the Small Cable Orifice
Location of the Small Cable Orifice on the Dyson Slim DC18.
Pic. 11. Location of the Small Cable Orifice.

My advice is to temporarily attach a drawstring, using a clove hitch, behind the cable retainer’s flange and bind the drawstring and wires with electrical tape. Be sure to keep the drawstring straight. Don’t wrap it around the wires or it will cut into them when you pull hard. Bend the longest wire back on itself so that the two connectors are not side by side (to keep the bundle slim) and tighten the tape around the soft flexible plastic flange of the cable restraint so that the whole form is as thin as possible. Then thread the drawstring through the small orifice and use it to pull the cable form through. Don’t tie the drawstring to the small hole in the cable retainer’s flange – it may rip open. See below:

Pic. 12. Binding the wires and drawstring with tape
Binding the wires and drawstring with tape.
Pic. 12. Binding the wires and drawstring with tape.
Pic. 13. The cable form and drawstring totally bound with tape
The cable form and drawstring totally bound with tape.
Pic. 13. The cable form and drawstring totally bound with tape.

“Alternatively get a pair of locking forceps to thread through the hole. Just make sure to grab onto the rubber mount assembly instead of the pressed-on brass connectors.” — Andrew Pardoe (25th August 2016)

9. Take the barrel wheel axle with an e-clip on one end and thread it through the hole in the outer piece of the Yoke.

Then engage it with the Undercarriage, the Barrel Wheel, the other side of the Undercarriage and the outer piece of the Yoke on the other side. Then fit the second e-clip by squeezing it onto the groove in the spindle with pliers.

10. Ensure that the grey peg on the undercarriage lever engages with the slot in the transparent disk.

If it doesn’t exgage it can’t rotate the Air Input Valve when the DC18 is moved between the upright and lowered positions. It was this peg that had snapped off which was the cause of my problem.

Pic. 14. Air Valve Operation
Dyson Slim DC18 Air Valve Operation
Pic. 14. Air Valve Operation

10.1 See how Bob Harris repaired his undercarriage.

Some people have opted to repair this lever and commented about it.

Below is the picture sent to me by Bob Harris:

Pic. 15. Undercarriage repaired by reader Bob Harris
Dyson Slim DC18 undercarriage after user repair
Pic. 15. Undercarriage repaired by reader Bob Harris

And here is some of Bob’s email:

A couple of snaps of the finished job are attached which is still working perfectly.  I gather chuck used glue whereas I went with two 8BA countersunk screws (remember BA threads?).
The red paint is simply because  I couldn’t lay my hands on my Loctite at the time and serves just as well as a bit of extra protection against anything shaking loose.  As you can see there isn’t a lot of spare space but there is enough if you use the right screws.

Part of an email from Bob Harris dated 16th April 2016.

Bob has also left a comment under the name Borris dated 14th March 2016.

10.2 See how Adnan Kitchener repaired his undercarriage.

Below is the picture sent to me by Adnan Kitchener of Ontario, Canada, who sent an email as well as a comment dated 25th November 2018:

Pic. 16. Undercarriage repaired by reader Adnan Kitchener
Undercarriage repaired by reader Adnan Kitchener.
Pic. 16. Undercarriage repaired by reader Adnan Kitchener.

11. Refit the upright position detection Micro-switch ensuring that the cam functions correctly.

See Step 4 above. Hold the cover in place with the T8 screw.

“Fitting the Micro-switch cover can be awkward. It can get covered up when the undercarriage is in certain positions.”

12.  Reassemble the connectors in the Cleaner Head Assembly socket and place it in its housing.

Then fit the Swivel Cover over it and hold it in place with the T15 screw.

13. Now check that the Undercarriage mechanism functions.

Don’t force anything to work. Dismantle parts and refit them if they don’t operate correctly. Check again that the Actuator for the Input Port Valve engages the slot in its transparent disc and rotates it, when the DC18 is moved between the up and down positions, before attaching the Hose Assembly that attaches to the Wand.

14. When the mechanism is OK, refit the Cleaner Head Assembly.

That’s so you can pick the DC18 up and stand it in an upright position.

With the DC18 upright:

  • Reconnect the Hose Assembly that attaches to the Wand.
  • Connect power and carry out a Suction test at the end of the hose.

Check the air valve changes the air input from the Hose to the Cleaner Head Assembly when the DC18 is lowered. Do this by Checking there is suction through the Wand/Hose when the DC18 body is locked in the upright position but not when it is lowered.

Check that air is being sucked in through the Cleaner Head Assembly when the DC18 body is lowered:

  • switch OFF,
  • remove the Cleaner Head Assembly,
  • switch ON and check for suction at the Cleaner Head Assembly connecting port.

If there is suction:

  • switch OFF and continue with Step 15 below,
  • else investigate the problem.

15. Finally replace the Outer Wheel Hubs.

Just align the fixing lugs on each Outer Wheel Hub with the central hole on either side of the Yoke Assembly and push evenly on the outer surface at the centre of the Outer Wheel Hubs until their lugs click into place. If not already attached, connect the Cleaner Head Assembly and wand. Perform a functional test.

Further Information

Further information can be obtained from the Official Dyson Community Support.




170 responses to “Dyson Slim DC18 Upright – Undercarriage Repair”

  1. Adrian avatar

    Thank you for this Colin. Your instructions worked perfectly and i now have a fully functional dc18 again. The only downside being that I’ll be probably made to use it again.

    Saved me a new vacuum cleaner though so thanks again!

    1. Helpful Colin avatar

      It’s a pleasure to help you.

  2. Rachel avatar

    Thanks Colin for the comprehensive instructions. When I spoke to the helpdesk at Dyson regarding the problem (small broken plastic bit – same as yours), although they were helpful, they suggested it was a near impossible task that they would have no idea of how to do it and they certainly wouldnt try to replace the undercarriage themselves, so good on ya!

    Its replaced and has even more suck than it did before & the roller ball moves more freely too. Im almost excited about being able to vacuum again! (OK so that bits a lie).

    PS: as an additional instruction, if you have trouble removing the roller ball end caps, you can raise the undercarriage to gain access to the back of the lugs with a long screwdriver to ease removal (I had trouble just trying to pull em off as you suggested)

    1. Helpful Colin avatar

      Thanks for your interest Rachel. I have edited the first paragraph of the Process accordingly.

  3. Markus avatar

    Top instructions, as with the others, saved me a new vacuum. Repair, reuse. Love it. Thanks so much.

    1. Helpful Colin avatar

      I’m glad I was of some help to you Marcus.

  4. Chuck Jensen avatar
    Chuck Jensen

    I was able to do a simple tab repair. Using a piece of metal, a 1/4″dia x 1/4″ long threaded spacer. I cut the metal into roughly the shape of the plastic the tab is broken off from. I drilled a hole for the screw and attached the spacer to the metal tab.
    I drilled a couple small holes in the plastic (for bonding grip) and using epoxy, I bonded the new tab piece to the plastic, positioning the spacer where the tab belongs.

    Parts; 1 steel nailing plate from hardware store fo the metal,
    1 screw to attach the spacer
    1 spacer obtained fro eBay
    1 tube of epoxy.

    Total cost; $1.50

    Pictures are available ifyou want them

    1. Helpful Colin avatar

      I’m sure you made a good job of it, and a lot cheaper than my method. I’m surprised you got the extra metal and screws to fit in the space available.

      1. Chuck Jensen avatar
        Chuck Jensen

        Hello, the metal I used is 0.04″ or a little over 1mm. It slips into the slot and is shaped like the plastic. I would attach picture but unable.
        Any way it is working great.

        1. Jerry P avatar
          Jerry P

          please send me the pictures of your DC18 repair. Hate to pay $65 for a ten cent piece if plastic. Thanks

    2. Cullen avatar

      Can you send me pictures of your repair. I am not sure about the clearances when in the upright position. Has the metal on plastic situation been ok? No apparent wear? Would love to save $60.00

    3. gary casares avatar
      gary casares

      can i see the pictures

    4. Tom Gainey avatar
      Tom Gainey

      Chuck – Can you send pictures of the repair? My tab is broken off as well – never saw the piece – so its a challenge to fabricate a new one.


    5. CullenT avatar

      Would find pics very helpful. Were you able to do the repair without taking the vacuum apart?

    6. jon gunter avatar
      jon gunter

      can you send me pictures to try and do the repair thanks

    7. Doug taylor avatar

      Please send photos! Thanks.

    8. jake avatar

      Mr. Jensen, please send me your pictures. I have the exact same issue with a broken tab and would like to save $60.

    9. Adriel avatar

      Hi Chuck, any chance i could see these pics?

    10. Marty avatar

      I would like the photos if still available. Thanks

    11. Everett avatar


    12. Helpful Colin avatar

      Hi Chuck,

      I can see there has been a long line of people who would like to see your pictures of the repair you made. If you can send them to helpful.colin@btinternet.com, as attachments, I will happily add them to my blog and give you full credit for them in my text. If you have any specific text relating to your pictures or design that you would like me to include then please let me know that too.

    13. Barrie Leete avatar
      Barrie Leete

      I made a card template then made a steel plate with a brass dowel to locate in the slot. I then fixed it into place with epoxy. Made from scrap so no cost and works perfectly.

      1. Barrie Leete avatar
        Barrie Leete

        It’s still working better than new and is used every day.

    14. Ed avatar

      Do you still have the pictures? I would like to fix it instead of replacing the undercarriage. Thanks.

    15. Sam avatar

      I always felt that parts can be made. If I had a picture of the actual part, so I can trace it to make addition/fix for new. I would appreciate it very much.

    16. Traci avatar

      Hi Mr. Jensen,
      My husband is very handy and would love to try fixing the vacuum Dc18 tab repair this way. Could you send me some pictures of all the steps. My husband said it would make it easier to follow your instructions.
      Thanks much

      1. Tom avatar

        I was thinking the same thing, however i was worried about why it broke. I thought some debris had clogged the rotating valve, and after clearing the debris, the valve was still “sticking” like something was preventing it from rotating. (which I think is what caused the tab to break off, or maybe the tab broke off and then the valve jammed). Just for science I disassembled further. After removing the carriage, I removed the plate that retains the valve, and slid the valve out. The valve is two plastic pieces and the two pieces rotate and slide in concert to move the opening to the correct locations. In one of the generous holes for the plastic tabs of the valve half, there was a piece of debris about as big as the plastic tab. This debris was jamming the rotating/sliding motion, and so the valve could only move a tiny amount. I’m thinking that with the long handle as a lever, when you rotate to activate the valve to the floor brush, the thin plastic actuator arm just snapped off. This piece of debris was “movable” so it sometimes jammed, sometimes did not jam, depending on the orientation. The debris was roughly cylindrical about 1/4″ diameter and 1/4″ long. Not sure if it was part of the vacuum, or something it vacuumed up. It was solid, but crushable between my fingers, like hard tar, or degraded plastic.

        So anyway if you repair the arm, I would suggest not only removing debris from the “tube”, but also, disassemble the valve, and check for debris within the valve mechanism.

        1. Helpful Colin avatar

          Hi Tom,
          Thanks for carrying out a thorough investigation and keeping us all informed.
          Regards, Colin.

        2. Will Ghates avatar
          Will Ghates

          Hi Tom .. Thanks for your insight. This is a perfect example of what a “planned obsolescence engineer’s job is”. This part was designed to fail and so it does. The repair part would not be expensive to make yet Dyson has chosen not to make this one part available even though they must make them for the under carriage unit. Why ??

          1. Tom avatar

            Being optimistic, my thoughts were that perhaps Dyson had made slight improvements in the undercarriage, to make the parts that usually break more robust. There is no way that Dyson cannot know that this part breaks frequently because of bad design. However, it looked like the new undercarriage was identical, with zero improvements. My second thought was that perhaps they had a well integrated design, in which all parts wore at about the same rate, so that with one failure it would be beneficial to replace the entire assembly to avoid a chain of failures. Upon disassembly, I did see other plastic parts were worn, but not to the point of failure. My third thought was that perhaps the plastic part is designed to fail first, when a jamming condition is found to save breakage in more expensive parts, but alas, if that was true, they would have many individual replacement parts available, rather than force an assembly replacement. I like to speculate, because having worked with a large manufacturer, I learned that there are many reasons why they sell parts, and their approach to customer service. Unfortunately the current thought of manufacturers seems to be how to maximize parts profit, versus saving customers money.

            1. Will Ghates avatar
              Will Ghates

              Thanks Tom – Great in depth analysis. I believe in exhausting all possible alternative explanations. I would like to believe in the inherit goodness of Dyson and their great products which obviously required a lot of thought, but alas you have arrived at the same place I have albeit from a more trusting perspective. A simple change in the manufacturing material for this 1 part would not be difficult. Aluminum or magnesium would work very well without changing any other specs. I guess Dyson would not sell as many parts then though …. I reinforced the new part with resin and carbon fiber before installation … I doubt I’ll be changing it again. This is a great site … thanks again for your insights.

  5. Jonathan G avatar
    Jonathan G

    Thanks Colin. You’ve just saved me the cost of a new vacuum and my wife things I’m a genius! I am hopeless when it comes to doing this kind of thing and even with your instructions I struggled a little. Probably took me nearer an hour. The most difficult bit was opening up the electrical socket as I was afraid of shattering the plastic, but I managed it in the end. It all went back together a lot quicker than it came apart. Thanks again.

    1. Helpful Colin avatar

      I’m pleased you were successful. I’m sure it must have boosted your DIY confidence.

  6. Steve P. avatar
    Steve P.

    Thanks so much for publishing this. I just fixed my wife’s DC18 and she’s happy again. And I didn’t have to fork over for a new unit. Just the under carriage. I did find it difficult to get to the four screws in step 4 before removing the roller ball and the assembly that holds the rollerball end caps. Once that assembly was out of the way, they were easy to remove. I reassembled in this manner and had little trouble.

    Thanks again. And yes, very helpful, Colin!

  7. Brad avatar

    Hey Colin – just wanted to say thanks for posting this. I had the exact same problem as you – the little tab that engages the clear disc was broken, and I had to rotate it by hand to switch from the floor brush to the wand! I Googled the issue, found your listing and wow! It’s the same problem! I ordered a replacement undercarriage from http://www.vacpartswarehouse.com (very quick and well priced!) and just replaced it tonight after printing your directions. Great of you to post this to help people out – I’ve got a new machine now for about $60!

    I agree with Jonathan G. – be careful when you open that little socket to hold the wires in place – it’s delicate!

    Thanks again Colin!

    1. Helpful Colin avatar

      Thanks for the compliment Brad. This has proved to be the most helpful article to date.

    2. Tom avatar

      I was able to remove the “plug” and wires without disassembly of the socket/wires, then attaching string to thread it out/in, as you show. There is a complex plastic piece that holds the plug, and it has 3 screws holding it to the assembly. Just remove the 3 screws and extract the plastic piece with the socket plug and wires, and once free, you can turn the socket such that it threads thru the plastic holding piece. Reassemble in reverse. Note the top/bottom orientation of the socket, or take a picture of the installed socket plug, so that you install it the same way, with white and black wires in the proper placement. The socket has writing on one side, and die marks on the other. Picture is best way to get it back the way it was.

      By the way, your procedure and pictures are very helpful, especially when it comes to reassembly of the carriage.

      Like other posts, the thin plastic piece is broken, and I could not find a replacement part, even though I was able to remove the plastic part from the carriage assembly. The piece that broke off, is lost, so I will not attempt a repair, since I don’t know the exact shape or tab placement. Surprised this part cannot be ordered.

  8. Jivey avatar

    All I can say is ditto to what Brad said and his problem. Thanks Colin, for the very helpful post and a working Dyson.

  9. Brandon avatar

    Fantastic! Thank you Colin. I just finished replacing my DC18’s undercarriage thanks to your help.

    1. Helpful Colin avatar

      I’m glad I helped you. Thank you for your positive comment.

  10. Roland avatar

    THANKS from California !! Colin, you’ve taken something appearing prohibitively complex and reduced it to a straight forward repair process saving a number of us much money. I purchased the under-carriage assembly on line, $56, and was able to replace it. Now running like new. Thanks for taking the time to photo-doc the process, incredibly good job.

    1. Helpful Colin avatar

      I’m pleased I helped you. I’m glad I took the time to photo all the parts. Sometimes I do jobs which I would like to add to my blog but I just have to get on with them and can’t spare the time to take photos all the way through, which is a shame.

  11. Dave avatar

    Colin, thanks very much for publishing this tutorial. I had the same part break, and my wife and I decided to order the undercarriage for $56 and do the repair ourselves. After 30 minutes of tinkering ourselves, we decided to see if there was a manual online. We stumbled onto your tutorial, and it took us through the disassembly and reassembly without any further hassle. We are very grateful! The photo-diagrams are a fantastic aid. Thanks again.

    1. Helpful Colin avatar

      I’m glad you were able to fix it. Thanks for the gratitude. This has been my most successful post to date judged by all the positive comments I’ve received.

  12. Steve North avatar
    Steve North

    Many thanks Colin easy and very helpful,timed myself from start to finish 69.37 mins.part cost £45.53 including delivery charge good saving on new Dyson.

    1. Helpful Colin avatar

      Well done Steve. I see you got yours cheaper than mine. It’s a pity DC18s have this weak point. Previously I had a DC03 which had several weak points. My DC31 Animal acquired from the Gadget Show at the NEC in April 2011 hasn’t developed any problems yet. It gets used several times per day – we have a dog. Dyson’s are getting better.

      1. Steve North avatar
        Steve North

        Many thanks Colin easy and very helpful, timed myself from start to finish 69.37 mins.part cost £45.53 including delivery charge good saving on new Dyson.
        As a post script Amazon UK was the cheapest place I found for the undercarriage.

  13. M.Padjen avatar

    On reassembly, is there a helpful hint to returning the cable and pins in the socket through that first entry in the undercarriage? Mine seems to get stuck at the end and will not go all the way through that tunnel in the undercarriage. I don’t want to damage the pin or wiring by using too much force. Maybe I’m doing something wrong?

    1. Helpful Colin avatar

      When I did it I didn’t have too much trouble. I suspect the retaining flange near the end of the curly cable is a bit too fat for the hole. I have dismantled part of mine to demonstrate how the wires and flange can be tightly bound with electrical tape to make them as thin as possible and how a piece of string can be tied to the cable to pull it through the hole with a bit of brute force but hopefully without any damage. Tie the string behind the cable flange – not to the end of the wires. See Dyson Slim DC18 Undercarriage Replacement Process section 8 which I have edited and included three more photos. Good luck.

      1. M.Padjen avatar

        Thanks so much for the update. Although I’m a do-it-yourself kind of girl, when I received my undercarriage part I felt a bit overwhelmed, until I found your blog that is. I was able to thread the wires through, but I feel like an idiot because my problem was that I could not figure out how to take apart the black connector from the wires. I was afraid of breaking the part and having to wait another week for a replacement. Anyway, I was able to complete the undercarriage replacement by following your very thorough instructions. Vacuum works great again. Thanks for taking the time to post the helpful information.

  14. M. Forester avatar
    M. Forester

    Colin, thank you, this was very helpful. In my case I needed to replace the Cleaner Head Coiled Cable Loom Assembly “DY-911049-02” on the DC18. The procedure is the same but there are a lot more steps once you have the base removed. The replacement is possible but it requires a ton of patience and additional tools.

  15. Tom Gainey avatar
    Tom Gainey

    Colin – Superb instructions, easy to follow. Fairly simple removal and replacement and no issues with threading the electrical wires and connector. – Just one suggestion – as you begin step 4, I removed the spindle and rollerball. It gave me more room to work in getting out the mircroswitch and was easy to see the wiring flow to be ready for reassembly. Think that others may find it helpful as well. Overall great photos and instructions. Dyson is repaired for around $65 and my wife is thrilled to have her machine back operational.
    Thanks Again!!

    1. Helpful Colin avatar

      Sorry for a delayed reply Tom. I have edited my post to reflect your suggestion. Thank you for it.

  16. Clare avatar

    Wow Colin!!!
    Thank you for your super-thorough instructions. Just done the replacement followed your instructions and it was totally straightforward.
    Saved us buying a new dyson!!
    Thank you!!

    1. Helpful Colin avatar

      Clare, I’m glad you’ve been successful. I’ve recently updated this post to improve it after receiving other comments. I included more pictures so that people can see extra detail before they proceed. I hope they helped you.

  17. mart avatar

    Colin: Just like everyone else, I wanted to say thank you thank you thank you! Your instructions made it easy for me — usually I’m inept at such stuff. I got the part for about 65 bucks delivered. Installed in about an hour. Much easier than I thought… And so, you’ve saved us the cost of a new vacuum. I hope to attempt over fixes in the future. Much better than just rebuying everything in life!

    On a technical note: In my case the wire assembly (not the microswitch one) slid back through with great ease. I don’t know if newer versions of the part have been modified, but the whole I needed to get it through was more than generous. MUCH more…

    Thanks for making the internet useful today.

    1. Helpful Colin avatar

      Mart, I’m glad I helped you. Well done for having a go yourself. I’m interested in the design of your DC18. My image with the caption “Location of Small Cable Orifice” in section 8 shows where my curly cable exits through the small hole in my machine. I would welcome any photo you have that shows how it is done on your machine. If its suitable I might edit my description accordingly.

    2. Helpful Colin avatar

      Hi Mart, If you want to send me an image, as I already suggested, you can email me at helpful.colin@btinternet.com

  18. Don avatar

    We’ll done Colin. Got a new undercarriage from amazon uk £47 free delivery. Fitted it in 20 mins. Very good instructions. Like a new Hoover !!

    1. Helpful Colin avatar

      Hi Don,
      Thanks for the good comment. As you can see I’ve received many on this article. It’s the most popular one I’ve written. After I changed my undercarriage the whole foot pedal system worked easier than it ever had, but I don’t know why.

  19. Tom avatar

    Colin, very helpful instructions. I also replaced the permanent hepa filter. Vacuum is like new.


    1. Helpful Colin avatar

      I’m glad I was able to help.

  20. Doylenn avatar

    Just did this to my dyson! It took about an hour but it works perfect again, thank you!

    1. Helpful Colin avatar

      I hope that’s the end of your problem. Good luck.

  21. Henry Berg avatar
    Henry Berg

    Did anyone run into trouble getting the rear wheels to deploy when raising the vacuum to the upright position? The motor on my vac went bad and when it came back from Dyson they missed a step somewhere and I have to lower the wheels again with my foot. Not a big deal and absolutely not worth sending it in for, I’m just wondering if it might be easy to fix myself. There’s clearly a button on the front of the undercarriage assembly that gets compressed in the upright position and *should* be causing the wheels to snap down but nothing happens for mine. The spring labelled 13 in the parts list (attached either to the pedal or the lock arm assembly) is clearly in place but that’s all I can say. I haven’t been able to deduce anything else by external observation.

    Great to see this post and the number of people who found it! I wouldn’t have expected it for a vacuum that had kind of a short run (at least, here in the US).

    1. Tom avatar

      Check the positioning of the spring, when the tab is engaged in the rotating valve. Also check the positioning of the “pedal” and locking mechanism. Both have to be oriented correctly to activate the spring loaded “deployment and locking feature. The pictures that colin has will help you get the orientation correct.

  22. Carl avatar

    Thanks for such a helpful guide, and saving me purchasing a new vacuum cleaner, took about 30 minutes altogether. Thanks for documenting as made the replacement straightforward, bought directly from Dyson for £41.60 although bloke on the phone said I wouldn’t be able to do it myself, what an idiot.

  23. Gavin avatar

    A really helpful guide, it made replacing the undercarriage on our Dyson a relatively simply job. Thank you for providing this useful information.

    1. Helpful Colin avatar

      Thanks Gavin. I’m happy that I helped you.

  24. Jon avatar

    Thanks for the walk through. 20 minute job with these instructions.

    1. Helpful Colin avatar

      I’m glad I helped you. Good luck.

  25. Andrew avatar

    Another one fitted here… thanks for the great guide, all went like clockwork, no issue with putting the cable back through neither.

    1. Helpful Colin avatar

      I’m glad you fixed it O.K. Andrew. Some people have difficulty with the cable and others don’t. Maybe some models have a modification which makes it easier.

      1. Andrew avatar

        Yep, was straightforward following your guide. The cable went through without issue, just fed it in from behind and the two wires came out the other side enough to grab and pull the curls through.

  26. mitchhanley avatar

    Dear Colin, thank you for the helpful guide. Unfortunately, I had to dismantle most of the unit in order to replace the damaged coil cable that powers the head. Your post helped me most of the way back, however, and I seem to have an extra spring that I cannot place. More concerning, though, is the spring which connects the wheel part of the undercarriage to the rest of the undercarriage. I had to guess that it connects to the screw underneath the micro switch housing (the top screw), but I think the spring is on wrong because it sticks up and out of the undercarriage alongside the duct assembly. Do you know what I am describing? I can send a photo.
    Thanks, for any assistance you can provide.

    1. Helpful Colin avatar

      Hi Mitch,
      I’ll try and help you. Please send photos to helpful.colin@btinternet.com
      Here are two photos one showing 3 springs visible from underneath and another which I have never seen but is obviously there. You can refer to the ones underneath by the numbers when you want to tell me about them.

  27. ray sterling avatar
    ray sterling

    colin, I replaced the undercarriage with your helpful instructions. now a new problem. overheats. not much suction coming out of the wand tube or the brush area, but tons of suction coming out of the tube that goes into the bin. I know I did everything right and everything works beautifully but the loss of suction and overheating. any clues? the only thing that didn’t seem right was the micro switch spring seemed a little weak like you described in item 4.

    1. Helpful Colin avatar

      Hi Ray,

      Sorry to hear you still have a problem. Overheating will occur if air cannot flow through the motor to cool it. So that will be fixed when you get the air flowing again.

      If the air changeover valve is working OK when you move from upright position to the lowered position you will have to look for a blocked pipe. Look at my post at http://helpfulcolin.com/2014/07/dyson-slim-dc18-filter-cleaning/ (or you can search on my site for ‘Dyson filter’). Fig.1 shows a ‘Block Diagram of Dyson Slim DC18 Air Flow’. The Interconnecting Pipe on the right, in Fig. 1, is the one with a circular orifice that you can see when the bin is removed. I presume that is where you have tested for suction OK. The Interconnecting Pipe on the left, in Fig. 1, is the one with the rectangular orifice.

      To test if the Cyclone and Pre-filter are OK: Undo the bin catch and allow a small gap to appear at the rectangular orifice so that air can just get in while the circular orifice is still sealed to the bin. You may need more hands to squeeze that side closed without closing the catch. Turn on the DC18 and test for suction at the rectangular orifice by inserting a sheet of paper and check if it appears to be sucked into the bin with a decent amount of pressure. If that looks OK you will need to check if the Interconnecting Pipe on the left or any other items to the left of that in Fig. 1 are blocked. Sorry to say you may have to dismantle some parts again if it gets to that stage. Tip: use long, stiff but flexible wire (e.g. as used for house wiring) to poke through pipes to check if they are blocked. You may be able to poke through the valve. Warning: Don’t move the DC18 from upright to lowered position with anything inside the valve or you may break the mechanism for rotating the valve.

      Good luck.

  28. rachel avatar

    excellent! thanks for taking thww time to post this. most helpful : )

  29. Jeremy avatar

    Most useful. thanks. A bit of detective work on the old unit showed that a screw had jammed the rotating air valve and this is what probably caused the failure. Pressing the pedal would cause the peg to try & turn the plastic disc, but snap when the disc wouldn’t, because the screw had jammed it.. Lesson, don’t force it in the future.


    1. Helpful Colin avatar

      Hi Jeremy,
      Those damn screws they get everywhere, especially in car tyres. I’m glad you resolved the problem.

  30. Scott avatar

    Colin thanks for taking the time to post this. Replaced the Undercarriage in an hour at a cost of $63.00.

    1. Helpful Colin avatar

      Hi Scott,
      I’m glad it went well. Just remember to keep washing the filter every 6 months. I keep forgetting.

  31. Bill avatar

    Hi Colin, Yours must be one the best tutorials for what is quite a complicated repair to a Dc18. What a pity the DC18 ( which I think is the best in the range ) has this inherant fault liability, it must cause the demise of the majority of scrapped machines and could have been designed not to break so easily.
    Wish you well and keep it up.

    1. Helpful Colin avatar

      Thanks Bill. Much appreciated.

  32. Monty avatar

    Thanks Colin…..your instructions worked like a champ. Replaced my undercarriage in less than 30 minutes & unit is like new! Appreciate your efforts in making the article. Saved me about $300 🙂

  33. Rob Turrentine avatar
    Rob Turrentine


    Thanks very much. I couldn’t have done it without you. You saved me a bunch of money.

    Good job!

  34. Stephen avatar

    Thank You for the Detailed Instructions, very helpful indeed

    1. Helpful Colin avatar

      Hi Stephen,

      I’m happy if I helped you.

  35. Terry avatar

    Thank you for this Colin:
    Your instructions helped ease my fear of tackling the job, Your photos are a huge help. I called Dyson first they said the repair was “Repair Center only” and they could not sell me the part, The repair center is an hour and half away in Paramus NJ . They informed me minimum “bench charge” was $150.00 plus parts plus and an hourly rate. I asked for the part # they gave me the part # for the yoke (DY-912365-01) instead of the undercarriage part (DY-912376-01) , I was glad I already looked it up myself. They offered to sell me a new Dyson at a discount $599.00, I declined their gracious offer. I found the part on-line $54.00 with free shipping , the entire repair took 1/2 at most. a hint for others when re-installing the rubber cleaner head pipe seal I was having difficulty getting the seal back on the hose as it was dry. I put some plumbers lube on it and it went together with ease, Vaseline would work just as well. As everyone once else has said my DC 18 works better than ever! it never stood up without manually engaging the the red lever, now it works as it should Thank you again.
    Regards, Terry

    1. Helpful Colin avatar

      Hi Terry,

      I’m pleased it went well in the end. Nobody wants you to be able to fix anything these days in case you save a buck or two, or (in the EU/UK) hurt yourself in the process.

  36. Moke avatar

    The info you provided was excellent and was a great help! Thank you for your assistance as the vac is up and running again!!!!!

    1. Helpful Colin avatar

      Hi Moke,

      I feel great to have been some help to you.

  37. Patrick avatar

    My wife never runs the vac but decided to clean up after the holidays. Caught her stomping on the assembly to get it to stand upright. Quoted her the part and figured two hours labor. Your article saved me. Took a little less than half an hour and it works perfectly. Saved my wife a lot in labor costs. (Of course I’ll never see that cash)
    Many, many thanks.

    1. Helpful Colin avatar

      Patrick this sounds like the beginning of a Happy New Year.

  38. Richard avatar

    Thanks very much Colin.
    I had the exact same problem with my DC18,
    ordered the undercarriage and followed your online instructions. I found then clear and precise and now have a fully operational vacuum once more.
    Richard (Bristol).

  39. eshapir avatar

    I just wanted to say a quick thank you. These instructions helped me repair a broken undercarriage that had a similar problem to yours. I spent $55 instead of $500 for a new vacuum.

    1. Helpful Colin avatar

      Hi Ethan,
      That’s great. I’m glad to have been some help to you.

  40. Borris avatar

    Hi Colin,

    This was really helpful as it enable me fix my Dyson but unlike you I elected to restore the functionality by repairing the existing undercarriage. After all it was only missing a very small piece of plastic with a spigot on it to operated the air valve…

    I pulled off the left hand wheel in order to get better access for drilling a couple of holes later on but that was the only dismantling I needed to do. I cut a piece of thin steel plate (about 1mm thick) to be about 2 inches long by half an inch wide. Drilled a hole at one end and attached my replacement spigot. I used a cut down standoff of the type used to mount the motherboard in a PC (I had a some round ones rather than the usual hexagonal ones). But you could just use a nut, bolt and a few washers. With the handle upright and the air valve in the corresponding position I insert the new spigot into the top of the slot in the clear plastic disk that rotates the air valve. The piece of steel was then just slid in the gap “in-board” of the broken plastic arm (that used to have the spigot on it) with the top edges of the steel and the plastic lined up. The two were then drilled and joined together with two small nuts and bolts. I used countersunk small headed bolts throughout to reduced risk of fouling during operation as space is a little tight. It’s also important to cut the bolts to exactly the right length after a trial fit.

    In summary I simply replaced the missing piece of plastic with a piece of steel which is much stronger then the original and should last indefinitely. The wheel was popped back on and everything works like new. Took about an hour and cost nothing as I used stuff I had lying about.

    But I couldn’t have done it without the inspiration given by you article though.

    Thanks again.

    PS The downside was that “Senior Management” was a tad disappointed she couldn’t have that new vacuum cleaner after all!

  41. Mike avatar

    Many thanks Colin – another grateful reader with a repaired Dyson

    1. Helpful Colin avatar

      Hi Mike,

      That’s great.

  42. Rick Carlos avatar
    Rick Carlos

    With your help I fixed our Dyson DC 18. Thank you very much.

    1. Helpful Colin avatar

      Hi Rick,
      I’m happy I was of assistance to you. You can tell the full story if you want. It might help someone else.

  43. mark avatar

    Hi Colin can you tell me the best place to order the rotary brush pipe for the slim ball dc18 or the lower duct pipe

  44. Randy avatar

    Excellent. Thank you.

  45. Bill avatar

    Thanks still rolling in, great job Colin.

  46. Richard avatar

    Screw this I’ll just buy a 50 dollar vacuum at Walmart. Probably last longer.

    1. Helpful Colin avatar

      Hi Richard,
      Well I only had to replace my undercarriage once. The machine is still in use at my Mother-in-law’s house.
      I have upgraded to a DC75 Dyson Cinetic Big Ball Animal. The benefits are:
      No bags to buy,
      No filters to maintain,
      No loss of suction,
      Designed for homes with pets. (We now have a dog.)
      There are no filters because it is capable of putting the finest particles into the bin with all the other dirt.
      I was lucky to see it nearly new on ebay being sold by a couple who had inherited it from a relative but already had that model themselves.

  47. Paul avatar

    Thank you Colin for providing a very clear photo of the DC18 Slim undercarriage so that I could see how to fit a replacement ‘Pedal Plunger’ and spring which broke recently. Such a simple part, but without it the machine will not stand upright. Cheers.

    1. Helpful Colin avatar

      I’m glad you had success. Well done and good luck.

  48. Andrew Pardoe avatar
    Andrew Pardoe

    Colin, thank you! A couple of suggestions:

    1. For the cleaner head power socket, snap a photo so you can match the colors when you reinsert them in the plastic plug. My DC18 has black and white wires, not brown and blue. Either the cleaner head is not polarized or I guessed correctly 🙂

    2. In step 8, rather than tying a clove hitch, get a pair of locking forceps to thread through the hole. I have a pair and they are fantastic for such jobs. Just make sure to grab onto the rubber mount assembly instead of the pressed-on brass connectors.

    3. Across the pond you can get parts from ereplacementparts.com. They have a nice site with exploded parts views for many products. (http://www.ereplacementparts.com/dyson-dc18-upright-vacuum-parts-c-179635_179636_508034.html) I bought the undercarriage without having seen your blog by referencing these parts views. I’ve also got a 14 year-old battery operated lawn mower that I’ve been keeping running with parts from them.

  49. Keith avatar

    Thank you Colin, I would not have been able to remember all of the subtle details of how to field repair a Dyson Vacuum. My wife did need to help with a flashlight and locating the right tools were a bit trying but the end result was well worth the effort.

    1. Mike D avatar
      Mike D

      Colin, Thanks so very much for your excellent instructions. I had the entire undercarriage removed, except for the Cleaner Head Power Socket, which, as you know, will not fit through the narrow sleeve in the undercarriage. Your helpful diagram and accompanying text assisted me in the last step in disassembling this socket. You saved me an expensive repair or the cost of a new vacuum.

      Again, much appreciated.

      Best Regards,

      1. Helpful Colin avatar

        Hi Mike,
        Glad to hear you were successful.
        Regards, HC.

  50. Vlad avatar

    Thank you Colin! My old Dyson stopped switching just after its warranty expired, so for a while I’ve been switching it manually, later bought a new model and the old one was sitting in the storage. Somehow I bumped onto your article, ordered new piece from amazon, paid $55 and now I have functioning Dyson.
    Thank you a lot!

  51. Robin avatar

    Is there a video on this repair? I was told by a servicer that its not worth repairing and to by a new Hoover.

    1. Helpful Colin avatar

      Sorry Robin, I don’t know of any such video. I haven’t made one and don’t have the easy access to this particular vacuum cleaner any longer so I can’t consider making one.
      One way forward might be to ask someone you know to be very good at dismantling and rebuilding technical items, that they aren’t already familiar with, to do it. If they will, just buy them the part and leave them to it. Try and get them to commit to a time period when they will get it done as it is common for people to put things off into the future.
      Regards, HC.

      1. Robin avatar

        Thanks for checking!

  52. Homar avatar

    Thanks for this detailed guide. Hope you can start doing YouTube video guides too if you haven’t already begun.

  53. Matt F avatar
    Matt F

    Thanks very much!

  54. Ellem Kay avatar
    Ellem Kay

    This is an excellent tutorial! The close-up pictures were indispensable. I disassembled my vacuum with no problems…except one. I forgot to mark the wires. When I reassembled the vacuum, I didn’t know how to properly fit the cables back in the housing. The 2nd picture in Step 2 shows the cable housing from underneath with a brown wire on the right and blue on the left, but my vacuum has black and white wires. With some research, I figured out why. The US and Europe use different wiring color codes. Basically, blue=white and brown=black.

    My vacuum does work perfectly again, so I can attest that this info worked for me. I also ran it by a friend who is very comfortable working with wires to double-check.

    If you want to verify or learn the function of each wire, I found the codes here: https://www.allaboutcircuits.com/textbook/reference/chpt-2/wiring-color-codes/. To see a US version of the wiring: http://www.dysonforum.com/viewtopic.php?f=5&t=314. The cables are coiled around each other in the picture, so look closely.

    1. Helpful Colin avatar

      Hi Ellem,

      Thanks for the comment. I have added those sites to my favourites and improved my post (see: “Dyson Slim DC18 Undercarriage Replacement Process” section 2 following the picture entitled “Cleaner Head Swivel and Socket Housing with cover removed.”)

      Kind Regards, Colin.

  55. Jim avatar

    Worked like a charm. Thanks a million, Colin. My wife thinks that I’m a superhero. . . I had to admit that I had a sidekick named “Helpful Colin.”

  56. Christine avatar

    thank you so much for this help. I’m female and not very mechanically inclined but I thought I would try and change the under carriage myself. Taking it apart was easy. I had a few set backs but took my time and after a few days I got a new Dyson cleaner that works awesome. If you had not had this instruction it would be at the repair shop now.
    Thanks again the pictures were so helpful.

    1. Helpful Colin avatar

      Hi Christine,

      I’m glad you were successful.

      Regards, Colin.

  57. spadesmaster avatar

    Thanks for this great post Colin, especially the super helpful photos. I’m quite technically inclined and this was a little more complicated than I thought and your ‘gotchas’ regarding the switches etc. were really helpful and I’m sure this saved me at least an hour of time I would have lost making an error. Now my DC18 is good for another 5-10 years of service!

    1. Helpful Colin avatar

      Hi spadesmaster,

      I’m glad you were successful.

      Although I have moved onto a newer Dyson, in my house, the DC18 is still running at my mother-in-laws. It’s still a model I like. The newer model has its own flaws (not serious ones).

      Regards, HC.

      1. Robin avatar

        I will have to live with the problem until I find a VIDEO ON YOUTUBE showing me how!!

  58. Christy Duke avatar
    Christy Duke

    Your instructions are fantastic, thank you so much! I am having a problem with the spring loaded cam. It is in the up position, and engaging the switch when the unit is not in the upright position. Any idea how to fix that?
    Thank you again!

    1. Helpful Colin avatar

      Hi Christy,
      Thanks for the compliment.
      This Dyson is now kept by my mother-in-law so I can’t just dismantle it to have a look. I think the cam should get pulled down when the Dyson cylinders are lowered to the ground. If that doesn’t happen you need to look in the workings of the undercarriage. When replaced the undercarriage is one complete unit so I’ve never dismantled it and looked in detail how it works.
      Sorry if I’m not much help.
      Regards, Colin.

  59. Brian Woods avatar
    Brian Woods

    Colin, I came across your instructions to replace the undercarriage on a DC18 Dyson Vac. Flawless instructions! Amazon carries the part for $55.00 US.

    Thanks. DC18 back in service.


  60. hotop1 avatar

    Thank you so much Colin. While I waited for my replacement undercarriage to arrive, I started the disassembly using Dyson’s limited diagrams. However I balked at removing the outerwheels until your excellent diagrams and instructions removed my fear of inadvertently breaking those tabs/clips off. I finished the job in under 20 minutes thanks to you. Hugely appreciative of the time and effort you put into documenting this process and removing the FUD of completing this myself.

    1. Helpful Colin avatar

      Hi hotop1,
      Nice to know you had success and the FUD turned into FUN.
      Regards, Colin.

  61. Mbehr avatar

    Thank you ver much for this write up. The level of detail in both words and images made the task very easy. We had put up with the sticking and eventual breakage of the wand suction and I was close to buying a new vacuum. Your write up convinced me this was a task I could do and in the end it was quite easy. It works like new.

    1. Helpful Colin avatar

      Hi Mbehr,
      It’s nice to know you were successful.
      Regards, Colin.

  62. Guy avatar

    Thanks for taking the time to do this. I’m about to replace the undercarriage on my Mum’s Dyson.

    It looks like the shop forgot to put the 4 x T15 undercarriage screws in the last time it was repaired 🙁

    Are you able to kindly confirm the type of screws used so that I can acquire some replacements please?

    1. Helpful Colin avatar

      Hi Guy,
      This model is now kept at my mother-in-laws flat so I can’t remind myself what these screws are like until Sunday.
      Anyway go here and have a look: DC18 Parts
      Then go here and have a better look: Enlarged screw
      I think it’s a black screw like this. Look carefully at the diagram. You might find one you can extract from another place to try in the place you need it. They look expensive to buy.
      You need a scrap dyson from which you can take the screws. Maybe there are many models from which you could get screws.
      Good luck with this one Guy.
      Regards, Colin.

      1. Guy avatar

        Thanks Colin, I ended up using some of the screws from the old broken undercarriage.

        Repair is now complete 🙂

  63. Roo avatar

    Great article, and like the others, completed it with minimal problems.
    Home Depot in the US has the tiny T8 driver in their HUSKY 8 bit set Item: 1000 039 344 (SKU#3872802335)


  64. Buzz avatar

    Bravo, Colin. I read through this description twice before ordering the undercarriage; the comments posted told me I had the tools, patience and know-how to pull this off. It did take about 90 minutes as it was new territory but by the time I was done I could do it again in 30. I’ll add this in case it hasn’t already been addressed: the undercarriage unit also included a nice new gasket that goes between the undercarriage and the vacuum body. I had everything put back together and then saw it inside the box. The old one was indeed very worn so after administering a dope slap I took things apart as far as necessary to install the new gasket, which made re-assembly a bit more difficult for some reason. But feels like I have a new vacuum cleaner and am confident I could repair just about anything else on it. Thank you so much for taking the time to post the most useful, informative and detailed repair of a great machine.

    1. Helpful Colin avatar

      Hi Buzz,
      Thank you for such a nice compliment.
      Regards, Colin.

  65. Adnan avatar

    Hi Colin,
    Thank you so much for excellent guide how to replace undercarriage. I guess Chuk never send you pictures how he had fixed broken tab back in 2013, since I am trying to do just that?

    Best to you,

  66. Will Ghates avatar
    Will Ghates

    Hi Brad, I scoured the Internet looking for the assembly which has this part (it’s attached to the wheel assembly carriage – a simple part) only to find every screw, switch, seal is available either from Dyson or from an OEM – EXCEPT for this one. One is required to buy the complete undercarriage. What a shame for Dyson to treat it’s fan base this way.
    Best price I found (with 2 day delivery) is at Amazon : https://www.amazon.com/Dyson-912376-01-Carriage-Under-Dc18/dp/B00Y35X5IW/ref=sr_1_fkmr0_2?ie=UTF8&qid=1543343472&sr=8-2-fkmr0&keywords=dyson+dc18+undercarriage.

  67. Natalie W avatar
    Natalie W

    Hi Colin,
    Thank you for such a detailed post on how to replace the DC18 undercarriage. We had the same problem as you (undercarriage not re-directing the suction to the hose) and during this replacement process I was saddened to learn that the DC18 is discontinued, that Dyson no longer carries parts and that none of my local vacuum repair centres were able to help. Thanks to online availability of the part, and your handy tutorial, I was able to do the replacement myself. I am glad to keep this machine out of the landfill and to save the expense of a replacement. Fingers crossed for another 10 years with this vacuum cleaner.
    All the best,

    1. Helpful Colin avatar

      Hi Natalie,
      It’s great that you repaired it successfully. I grew up in a household where repairing items was the norm. I see it as a sustainable approach to modern living.
      Fortunately in Europe electrical items aren’t allowed to go straight to landfill. They have to go through a reclamation process when disposed of. My local tip has a special area to collect washers, fridges, TV’s, Computers, etc..
      Regards, Colin.

  68. Ryan avatar

    Colin – Thank you for this guide. It told me everything I needed to know to make the repair on my 10 year old DC18. Now she’s running again like a champ. I couldn’t have asked for a better guide. Your website is a true gem. Please keep up the great work.

  69. Maverick avatar

    Thanks for your helpful article. I have a same DC18, where motor overheats and it shuts down after a few mins(4-5mins)

    Have already cleaned lower brush area, all filters. If I remove the cyclone and filter body, there’s a lot of suction on the hole which goes into the cyclone, but the wand has very minimum suction.

    I feel like, there’s some blocking, maybe in the lower ball area, is there a way I can validate it? Thank you 🙂

    1. Helpful Colin avatar

      Hi Maverick,
      You should remove the Cleaner head from the front and the wand’s flexible hose from the back. It clips in where it bends at the bottom. You may find dirt there. See Pic. 9. (I have just numbered all the pictures for easy reference and editted it too.) Pic. 9 shows a short flexible hose which joins the wand’s hose to the port on the undercarriage (I’ve called it the Hand Tool Hose in the pic.) With that short hose disconnected and the Cleaner Head disconnected you should gain access to the changover valve which directs air from the cleaner head or the wand according to the attitude of the cleaner body (i.e. standing up or at an angle towards lying down). Check if the valve is clear of dirt and works when the body is lifted up and down. You should be able to check that short bit of Hand Tool Hose too. Anyway you should get better access to all the airways. Beyond this you would have to get a screwdriver out.
      Regards, Colin.

      1. Maverick avatar

        Thanks very much, yesterday I removed all the visible screws from Pic 1. Cleaned the valve where wand hose goes, that port was super dirty. Now I have to re-assemble and not sure if I can do it easily?

        Would you have any advise on putting Pic1 back with the whole assembly? Thank you

        1. Helpful Colin avatar

          Hi Maveric,
          This is a bit tricky. The undercarriage in Pic. 1 comes as a complete unit. So I have never broken it down into smaller pieces. You might have trouble with springs, i.e. assembling any that there are so they do their job.
          The secret with these jobs is to take photos as you dissassemble. Please let me know if you have any problems with springs not working and parts left over when it looks complete. I may still have my old broken one to look at.
          Regards, Colin.

          1. Maverick avatar

            Thanks again, while I am at it, is there any other port or area I should be cleaning? Also, if you can please share a picture of the spring/s location and alignment, that would be much appreciated 🙂

            I have a feeling, that wand port cleaning would fix it, all other parts seem to be there.

            Thank you again 🙂

            1. Helpful Colin avatar

              Hi Maverick,
              I presume you’ve made some headway.
              The metal wand and its long flexible pipe can be checked for total blockage by looking down them or dropping something heavy (like a screwdriver) down them while they are disconnected from the cleaner. If it doesn’t pass through you’ve got a problem.
              Another place to clean is the outlet pipe from the cleaner head and inside the cleaner head, especially where the drive belt connects the small motor to the rotating brush. See Dyson Slim DC18 Cleaner Head Maintenance.
              I’m not sure how much I can help with pictures of springs.
              Regards, Colin.

              1. Mav avatar

                So I was able to assemble everything just by looking at the pieces and seeing where they’ll fit.

                Blocking in the wand inlet area was the reason for running hot and cutting out, assembled everything and it’s a runner 🙂

                Thanks for all your help.

  70. Sunny avatar

    2021 and Helpful Colin you are still helpful sharing this wisdom. I rigged a metal PCI computer slot cover, bent the “L” shaped top piece into a cylinder after a few snips with metal shear scissors and small pliers to adjust fitment into the clear wheel slot for the actuator/wand switchover. The larger length of the PCI slot cover was screwed to the gray plastic in a staggered manner. Same problem as you had originally – tiny plastic spigot sheared off. DC18 Now fixed! All the DIY knowledge and diagrams were a great guide, thanks.

    1. Helpful Colin avatar

      Hi Sunny,
      Well you and one or two others have gone to town on repairing this part. Well done. In my case, as you know, I acquired a new undercarriage. If that one had gone on to break too I would be cursing. However it’s still good.
      I use a later model at my house now, but I still keep the DC18 at mother-in-laws where my wife does the cleaning and it has survived well.
      Regards, Colin.

  71. S2TPW avatar

    Hi Colin

    Your guide still doing the trick and nearly in 2022!
    Undercarriages now only available as used, but seeing other repair solutions means I will try that if I need to …next time

    1. Pedro avatar

      Hi Colin,

      Thank you for your helpful post. I found a DC18 on the side of the road that among other things needed the broken tab replaced. I fashioned a flat piece of plastic into the correct shape and screwed a screw at the end of it and then used a nylon wall toggle to cover the screw and then used epoxy to secure it in place. The repair is a mix of Bob and Adnan’s repair. Putting the plastic in the position that Adnan has it prevents the folding mechanism from fully closing. I have some photos to share if anyone is interested

      1. Helpful Colin avatar

        Hi Pedro,
        It sounds like you got a bargain with that one.
        Thanks for keeping us all informed.
        Regards, Colin.

  72. Kurt Gibbings avatar
    Kurt Gibbings

    Hello Colin, thanks for detailed info on your blog!! I have a DC18 and the brush roll isn’t working. I measured 16V AC at the output of the two prongs from the main unit (which plug into the brush roll). Is this voltage normal? I’m in the US so we use 120V AC. Seems odd to me that the brush roll motor would operate at this voltage. Thanks again!

    1. Helpful Colin avatar

      Hi Kurt,
      I have passed my DC18 on to someone else now so I don’t have one I can measure and I never measured it when I owned one so I can’t give you good advice.
      Check out what Pedro has to say. Maybe he can help you. Good luck.
      Regards, Colin.

  73. Pedro avatar

    Hi Kurt. I tested mine (which is working) and I get 8V AC when the brush roll button is activated and 4V AC when deactivated. I’m in Australia and our voltage is 240V. The brush roller is easy to dismantle so you could investigate the wiring and motor

  74. Tony avatar

    Hey Pedro,

    I’m interested in pictures of your repair. I’m trying to fix my now.

  75. Pedro avatar

    You can find the photos here: https://imgur.com/a/fWAugNM

    I added some small nails trimmed to size to the flat plastic sheet to give the epoxy something to grab. I drilled some holes into the sheet for the nails as hammering them in directly fractured the sheet. I then used a soldering iron to push the heads flush with the back of the sheet. I misaligned the holes that I drilled initially but this may have actually helped as it allowed the excess epoxy to squeeze out when I clamped it in place.

    To make things easier there is a piece that is above the red pedal that is held in by two screws that you should remove first. This will give you better access to the back of the plastic that held the plastic tab before it broke off.

  76. colin krawcyk avatar
    colin krawcyk

    Hey thanks for this site, I ended up doing a 3D printed repair based on others work here. Please find it here if you want to use it!


    1. Helpful Colin avatar

      Hi Colin,
      This is very interesting.
      I’ll probably chat to my nephew about it because he has a 3D printer.
      It’s good that you mentioned it and gave a link so we can all see it.
      Kind regards, Colin.

  77. Vicky avatar

    I wonder how Colin Krawcyk attached the 3D printer peg back on to the lever. Can we have a follow up?

    1. Helpful Colin avatar

      Hi Vicky,
      If you follow Colin Krawcyk’s link you will see in his summary that he used epoxy resin. If you’re not familiar with any brands consider Araldite.
      When using epoxy resin with plastic it can be beneficial to not only make the parts clean but to rough them up with abrasive paper.
      Regards, Helpful Colin.

  78. Doug Randall avatar
    Doug Randall

    I am so grateful for the time you took to do this careful walkthrough. I just used it to replace the motor and complete wiring harness on my Dyson DC-18 successfully. Yes, it took several hours and was a “big job”, but with the walkthrough to get past the many parts that otherwise would not have been obvious, I took on the job with confidence and saw it through. Thanks again.

    1. Helpful Colin avatar

      Hi Doug,
      It’s pleasing when a hard task goes well.
      Great job.
      Regards, Colin.

  79. Peter Hatfield avatar
    Peter Hatfield

    Wow – what an excellent “how to”. I arrived at this tutorial while looking for a replacement undercarriage that is no longer available anywhere, but I was curious as to how to dismantle the machine. Then I came across Bob Harris’s repair, and thought, “I can do that.” And I did. I managed to effect a repair with a slim piece of stainless steel with a cut-down sparking plug screw top as a spigot (4mm thread). I didn’t even have to dismantle anything, apart from removing the left wheel to gain clearance for a drill bit. Thank you for doing this – very impressive.

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