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 FAQ #131
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How can I change the rear Brake Pads and Discs on a Citroen C4
Citroen C4 – Rear Brake pad and disc replacement (Bosch Type)

Tools required (for pad and disc removal):

Wheel removal tools.

13mm Socket – for removal of floating caliper screws x2

T50 Torx head – for removal of fixed caliper screws x2 (Motorworld £10 for set)

Piston pushing tool – for pushing and turning of pistons back into calliper (Halfords £21)

32mm Socket – for removing hub nut (Halfords £6.30)

Extendable socket wrench – if you’re puny like me, always useful to keep in the car for when you’re changing a wheel by the roadside and the wrench in the spare wheel is just not long enough. Also, highly recommended for removal of the hub nut

Chisel and hammer – for removal of the hub nut cover

Claw hammer – for removal of the ABS ring

Important: I am not a mechanic, having only basic car skills. Therefore, some procedures noted below are best performed using proper tools. I can in no way be held responsible for any damage occurring to either you or your vehicle should you decide to follow this guide. As always, a common sense approach should always be taken.

It is recommended that FAQ#50 (replacing the front brake pads and discs) is read first. It goes into details about how brakes work, and the process of changing the pads alone is almost identical, save for the rear brakes having a handbrake cable.

I would imagine the Lucas assembly is very similar. The discs are the same, but the pads are different, so be careful when ordering parts.
Steps marked D. need only be performed if changing the discs.

To start:

Take a drive around the block, use the brakes as little as possible. Check the warmth of the discs. They should be pretty cool. This gives you an indication of any problems when you repeat the process after changing the discs/pads.

When jacking the car, replace the jack with an axle stand or similar. Never work under a car using just the jack. Also, ensure that all wheels on the ground have chocs around them. You will need to release the handbrake to change the brakes.

Also, when the car is jacked up, give the wheels a spin by hand, and see how easy they are to turn. Another sign of binding will be if the wheels do not turn well after working on the brakes.

Repeat this process on the discs after the wheels have been removed.


They say that you should use brake cleaner to clean off the brakes. I just used a small wire brush and a toothbrush to clean most of the crud off. I put on a face mask, as although they’re not made of asbestos any more, the dust is still pretty nasty.

People also recommend using a barrier cream on the hands to make it easier to clean them after. I didn’t, but 5 days on from the job, they’re pretty clean.

1. Remove floating calliper – simple task of removing the two screws behind the assembly. It may make it easier to unclip the handbrake cable. When removed, do not let the assembly hang by the hydraulic tubes.

The image shows the location of the two screws (circled), the handbrake cable that can be unclipped (arrowed), and the impression of the branding on the caliper.

Image shows the released floating caliper. Note that the head of the piston has two notches in it. This is for the piston tool to locate on.

2. (If you are just replacing the pads, do this step. If you are also replacing the disc, perform steps 3&4 first)

Push in the piston. Remove the brake reservoir cap in the engine bay. Keep an eye on the fluid levels, as pushing the pistons in will raise the level. Keep something handy to siphon off any excess. This fluid is corrosive, so you don’t want it spilling!

When pushing the pistons in, they also have to be wound. Because of this, it is very sensible to have a correct tool, as without it may be difficult

I strongly recommend winding the pistons in, then letting them out a couple of times, to ensure nothing is sticking. In this way, on the second or third repeat, it should get easier to wind the piston in.

’Laser’ brand piston tool. Winding the screw pushes apart the head that is in contact with the piston away from the back-plate. In this photo, steps 3&4 have already been completed.

3. Remove old pads and clips. Keep the clips safe!

4. (D) Remove the fixed part of the caliper, using the T50 Torx head. These are quite tough.

5. (D) Remove the hub nut cover. I used a chisel, gently tapping around it. After a while, it will come off. The edges can be tidied up when placing it back on after the job is complete.

6. (D) Remove the hub nut. For obvious reasons, this is on tight. Remove the old disc.

7. (D) Depending on where you got your new discs, they may or may not have an ABS ring on them (example, EBC never supply discs with ABS rings). This is a metallic ring with embedded magnets that ABS sensors pick up on to measure the speed and pulse the brakes accordingly when ABS is active. If you compare the new and old discs, you will easily tell if the new ones have them or not. If not, either get a new set, or remove them from the old discs.

I took the dangerous (and therefore not recommended) approach of easing them off using a claw hammer. Put one claw under the ring, using the disc to rest the pivoting part of the hammer. Gently tap the hammer head with another hammer, and circle the ABS ring. It will eventually come off. To attach to new disc, use a flat piece of wood over the ring to gently put it in place. Also remember to clean off the new discs with white spirit or similar.

Location of ABS ring on old disc. When covered with grime, it is hard to see the ring. However on comparison with the new disc, it is obvious that the profiles of the two are different if the new disc doesn’t have them attached.

8. (D) Put new disc on, replace hub nut Tighten to 9 ± 0,9 m.daN -Angular tighten to 29 ± 5 ° (75lb/ft) - refit cover

9. Assemble calliper brace, clips and new pads.

10. Assemble calliper.

11. Pump the brakes a few times to push the piston onto pads. Check that you can still turn the discs by hand.

12. Replace the wheel, and give that a good spin. If it does 2 or more revolutions, then it should be OK.

13. Replace brake reservoir cap! Drop the car, start up, and give a quick test up and down the road/driveway. This is to check a. that the brakes appear to work, and b. to check that the ABS ring is correctly in place (if it isn’t the dashboard will light up like a disco, warning of ABS and ESP faults).

14. Repeat process for other wheel.

Test drive – firstly take car for short spin (2-3 miles), using brakes as little as possible. Check first that the wheels themselves aren’t getting warm, then check the discs. My advice is to first perform the spit test before touching. If the spit vapourises, then the discs are getting too hot. You should expect them to be a bit warmer than the check performed before doing the work.

If they are getting hot, the most likely cause (in my experience) is that the pistons are sticking a bit and therefore the pads are remaining pushed against the discs. Take the calliper out, and repeat step 2.

For the actual wearing in of the pads, there are plenty of opinions on the best way to do this. I found that the brakes were pretty good straight from the set-off.

The above was carried out on a Citroen C4 HDi but as the brakes are common across all the range including the C4 Picasso should be useful for everyone.

BigJohnD wrote ...

Today Barrie (and I, but mostly Barrie) replaced the rear discs and pads on my 55 diesel VTR+ after 74,000 miles, in time for my 75,000 miles service.

First all, thanks to Alex (aka amjl2000) for his excellent How To - Click Here - on changing the rear discs and pads, and I'm going to make a few observations from our experience today.

The job is technically very straightforward:

1. Jack up car, make safe and remove rear wheel.

2. With a 13mm spanner, remove two bolts retaining the floating calliper.

3. With a T50 Torx, remove the two set screws fixing the piston/calliper to the back plate.

4. Push out the pads and retaining springs, and remove floating part, being careful with the fixed part, as that's now hanging on the hydraulic pipe and is still attached to the handbrake cable, which doesn't need to be disconnected.

5. Remove the cap over the retaining nut in the centre of the disc, and with a 32mm socket, undo the nut. (Our socket had a ¾" drive so an adaptor to ½" was needed.)

6. Remove disc.

7. Put on new disc, tighten nut to 90Nm + 30°. Lock the nut using a nail punch. Replace cap.

8. With piston rewind tool, push piston back into cylinder, keeping an eye on the fluid level under the bonnet.

9. Put new springs and pads into calliper and re-assemble with new bolt, using Copaslip and Loctite appropriately.

10. Check everything before putting wheel back on, and lower car to the ground.

11. Pull up the handbrake several times to take up slack and pump the brake pedal until things stiffen up. Check fluid reservoir under bonnet.

12. Go for test drive to initially bed in the pads and check for faults, squealing, etc.

Sounds simple, doesn't it? Right, here we go!

An IMPACT DRIVER is needed to remove the Loctited T50 set screws. After 70,000+ plus miles of heat, frost, filth and wet, you just can not release them using a basic ratchet or similar. We, (well Barrie) was battering the impact driver with a 4lb lump hammer and almost knocked the car off the stand before we could turn them with a massive extension on the Torx bit. The nearside was made more difficult because of the proximity of the exhaust.

Secondly, to rewind the pistons, a LEFT-HANDED rewind tool is essential to push the RH/driver's side piston home. If you do not have a left-handed rewind tool, do not start this job! Your car will be stranded on the stands until you get one - guess how we found that out! The piston will NOT rotate clockwise, and it cannot be pushed straight in - it must be rotated anti-clockwise into the cylinder.

Yes, we didn't have a L/H rewind tool, but eventually found a guy in Wheels Auto Parts & Accessories in Chorley who a) believed us when we said we wanted a L/H rewind tool (the bloke in Halfrauds thought it was a wind-up), and b) found one for us in two hours (which meant we had time for several nice coffees and a long chat!

The Left-handed Piston Rewind Tool

This not the best of close-ups, but note the "L" to indicate Left hand thread.

Details of the tool we used. Note it specifies C5, and there's no reference to a C4. It might make things easier if you're searching for the tool to talk about a C5.

Some more photos:

Old and new discs.

These were genuine Citroën, part number 4249.34 and were a straight swap, complete with wheel bearing and ABS ring, clearly visible in the photo. (I wasn't sure about Alex's comments about the ABS ring - everything is as it should be…)

New pads. Part Number 4254.76
Note plastic cover over sticky anti-squeal shim.

Old pads, down to a couple of mm. Note the C4 does not have a pad wear indicator system.
After 74,000 miles, the anti-squeal shims fell off and almost disintegrated!

Done! Nice new shiny discs.

During the journey home from Barrie's, the pedal firmed up nicely and the pull on the handbrake returned to normal. There was no squealing or ABS/brake warnings.

The parts were supplied by [ Dealer 1 ] at a big discount (I collected them in person to save on postage - these things are heavy) and saved around two hours labour time, which at Citroën dealer rates is probably £200.

So thanks again to Barrie for his great help - I'd never have done this without him - and to Theresa for help, tolerance and excellent cups of coffee.

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FAQ Posted by amjl2000
Info Created: 08 March 2009
Last Updated: 01 March 2014
denerobt 26 Mar 2009 : 06:29

With the tool, don't you also have to have a left hand one to wind the back driver side into it's housing. Currently having a devil of a job winding the rear driver side one back with this tool

jimbobfruitbat 02 Jul 2009 : 02:50

Is it essential to wind the piston? The front brake pad replacement guide doesn't mention this, and many other guides just advise on using a G clamp.

jimbobfruitbat 20 Jul 2009 : 11:46

Update to my last post. Yes of course it is necessary to use the piston winding tool. As to the need for turning the offside piston anti-clockwise, well that may depend on your vehicle. I simply needed to turn both near and offside pistons clockwise, using the same tool (incidentally, there is a technique for using the right-threaded tool to wind a piston anti-clockwise, if you have the other type of brakes which need this).

Finally, I needed a 36mm socket rather than the stated 32mm socket to remove the hub on my rear wheels. So, be prepared. Or at least, remove the hub cover and check before you go and buy any tools!

gmerry 11 Dec 2009 : 14:16

Hi, I have a Draper "cube tool" with prongs on five sides. The tool number is CWT1. Will this tool be compatible with the Lucas rear brakes in terms of winding back the pistons


lodgy 22 Jan 2010 : 10:43

Reference Hub nut torque: Is there a more lamans terms as I am used to Nm + a degrees....?


Bumps 28 Jul 2010 : 23:47

I know this is an old post, but as a FYI, it is possible. I've just replace pads using the 'cube' tool. It just takes a hell of a lot longer, just need to keep winding the piston down with some pressure on it. Next time, I'll order a piston tool kit off ebay from the UK. I'm located in Sydney, OZ and the same kits are going for 2-3times in Australia, inclusive of freight.



C6 Dave 29 Jul 2010 : 02:27

75 lb/ft

robbie-rocket-pants 14 Jan 2011 : 11:46

Just changed the pads on my C4 VTS 180. It has Lucas calipers. After much fettling I realised that both offside and nearside calipers need to be wound clockwise
Also, I didn't bother with a special wind back tool, I just used a large bolt, washer & nut to press on the piston and an angle grinder disc removal spanner to twist the piston (the prongs on the spanner fit perfectly into the grooves in the piston)

Ham 20 Feb 2011 : 15:00

What are the torque setting for caliper bolts and caliper cradle?

NIKOC4 27 Nov 2011 : 07:49

the screws wich need a T50-55 torx head are stuck and im scared that i will destroy the screw if i try to hard(happent last time, i tryed it was too hard and at the end i broke tha head and after i destroy the gap were the t5O goes in....)

any ideas how i can loosen the screw?????

C6 Dave 27 Nov 2011 : 08:00

Please post support requests in the forums

Ksneps 25 Dec 2011 : 14:51

IF YOU DO NOT HAVE REWIND TOOL TO PUSH PISTON INSIDE floating calliper - do not trie to change rear brake pads. I'm not specialist in these thing - but it looks like it is impossible to push piston inside without it. I lost too much time and effort to do so. So... I'm next client in line to local dealer.

alfsgc4p 27 Sep 2014 : 13:54

This topic needs updating...I'm currently changing the rear brake pads on my 2007 vintage Grand C4 Picasso and I thought I should address a few things stated before.

Firstly, contrary to the previous advice given above you DO NOT need to use a impact driver to remove the two bolts holding each calliper on. First make sure you have a decent quality T50 Torx bit...A cheapo one like a Rolsen may seem like good value but they are worse than useless for this job and they can actually damage the Torx socket on each bolt head when you have to hammer them in to make them fit! (I found this out to my cost)

I got a good quality Neilsen one for £5.99 which has a 1/2" drive on the other end...I recommend you do the same. A very short extension bar (2") is also a good idea or you may find you don't have enough clearance.

Use a 1/2" ratchet that is at least 12" long (I use an old 12" torque wrench) or you wont get sufficient leverage to undo them. Tip: You can use a piece of tube slipped over the handle of a shorter wrench to extend its length. If it seems like it wont budge use a plumbers blowtorch (with a narrow jet of flame) to heat the head of the bolt for about 30-40 seconds. You should avoid over heating it and of course make sure you avoid the nearby brake pipes! You should find that the heat has softened the locktite (the blue gunk on the thread that is stopping the bolt undoing)and the bolt will now undo easily. It worked for me.

I question if the offside (drivers side) wind back tool needs to be a left handed one...The nearside one is definitely left handed but I am having major trouble with a left handed tool on the drivers side...I may have damaged the thread on the piston yesterday because I had not read this thread and thought I could just push the piston back in with a 6" G-clamp...

I bent the frame of the G-clamp trying it! Today I went out and bought a Pagid Professional "18 piece brake piston wind back tool set" for £48...Its come with both left and right handed wind back tools...It make the passenger side easy to do but the tool is currently jammed in the drivers side calliper and it wont budge!

alfsgc4p 03 Oct 2014 : 13:57

The rear hub nuts on my Grand C4 Picasso are 36mm, not 32mm as stated above! A 36mm impact driver socket with 1/2" drive is £12.99 from Halfords.

alfsgc4p 04 Oct 2014 : 12:46

Warning! Contrary to the advice given above you need BOTH left and right handed wind back tools to change the rear brake pads! Well at least on a Grand C4 Picasso...The near side/passenger side/left hand calliper requires a left handed wide back tool but the offside/drivers side/right side requires a right handed wind back tool...I found this out to my cost when I tried using a left handed tool on the right hand calliper and got the tool permanently jammed solid in the calliper! I had to use an angle grinder to cut the calliper apart to get the tool out, rendering the calliper useless! A new calliper is over £160 so it could have been a very costly mistake but luckily a replacement calliper was just £30 on ebay so I was able to change it a couple of days later. So remember, if you wish to avoid mistakes like I encountered, ignore the advice in the original article and get yourself both left and right handed wind back tools for changing the rear brake pads.

BigJohnD 17 Nov 2014 : 09:09

>> ignore the advice in the original article and get yourself both left and right handed wind back tools for changing the rear brake pads. <<
The article indicate you do need both LH and RH rewind tools.

It states: "Secondly, to rewind the pistons, a LEFT-HANDED rewind tool is essential to push the RH/driver's side piston home. If you do not have a left-handed rewind tool, do not start this job! Your car will be stranded on the stands until you get one - guess how we found that out! The piston will NOT rotate clockwise, and it cannot be pushed straight in - it must be rotated anti-clockwise into the cylinder."

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