C5 Mk1 2001 2.2Hdi - Replacing Rear Brake Calipers And Discs

[aspire_helen]

Hi, just thought i would share my experience of replacing the rear brake discs and calipers for the first time after 13 years and 150k miles.

Firstly, i advise whenever inspecting the rear brake pads and discs ALWAYS check the inner pad and inner disc face.  I found that since the last mot (11 months ago) both calipers had been pushed out by corrosion and the discs were cutting into the caliper bodies - not uncommon.  More alarmingly one caliper bolt had sheared and neither of the inner pads were bearing on the discs such that the disc inner faces were almost entirely rusted.  However, the outer pads and disc faces looked deceptively fine!  One might think a difference in braking must have been apparent, but i am a cautious driver and tend not to use the brakes heavily.

I had to use an impact driver to free the 2 disc retaining screws; the disc came off with a bit of a hammer. The worn disc and distorted calipers allowed the disc to come off completely. Note- a new disc cannot be fitted with new calipers in place - fit the disc first!

I used a 16mm impact socket and a 3ft lever to unscrew the caliper bolts. It takes loads of effort and patience, but they do eventually unscrew. The resistance is due to the loctite in the calipers, not the screw threads. Unscrew each bolt half a turn at a time alternately. The caliper will come way with the bolts still in them. Dont bother trying to remove them, just replace the calipers. New bolts have to be fitted anyway and the old calipers are likely to be too corroded.  Indeed, on both calipers the holes locating the pad retaining bolts had corroded away completely.  During the bolt unscrewing, one caliper split appart leaking brake fluid, the other stayed fixed together. I sealed the brake feed pipe using a female to female connector with a bleed screw.  The sheared bolt left 3mm of thread protruding from the screw plate on the suspension arm, so i welded a nut to it and teased it out no problem.  

I tidied up the face of the screw plate by chiselling off the 2mm thick alloy corosion, sanded it down and applyied rust converter.    For the reassembly, i used loctite as advised by haynes - 510 for the joining face, and 270 + 7649 activator for the bolts.  My thinking is that hopefully i will not have to do it again, so do it properly. I believe that citroen had to resort to loctite to correct a poor design fault. 

All the extra tools, loctite, parts, consumables etc came from ebay, except the caliper bolts from citroen £13 for 4. Ive refitted Brembo discs and pads £74 for the full set.   The calipers £66 the pair seemed cheap, but they appear quite good. They came with bolts (to keep the 2 halves together, not to use as caliper bolts!). They also came complete with the pad retaining bolts and cover plates - i note gsf for example sell them as an extra £10 "fitting kit".   Nevertheless, i bought some stainless steel retaining bolts and nuts £1.40 for 5. I also fitted stainless disc screws £1.15 for 5.  Time will tell with the caliper quality but they came with a 2year guarantee. Total cost, about £200.

Now all i need to do is bleed the system and renew the brake fluid - see my other post seeking advice on this ! http://www.citroen-owners-club.co.uk/citroen/topic/22073-c5-mk1-2001-22hdi-advice-on-brake-bleeding/

 

The lesson i have learnt is to thoroughly inspect your brakes regularly and not leave it to the mot or service (especially for low mileage biennial service). Once the seal between the caliper and suspension arm is broken, the galvanic alloy corrosion will attack mercilessly in a single salty winter.

[paul.h]

I would not put too much hope on not having to clean the calipers again. Our 2004 C5 was less than 2 years old, 16k miles, when we got it and the rear discs had corroded, the pads seized and lots of corrosion on the back of the calipers. Since then I have been doing them every 1 or 2 years on the old C5 and now our 2007 one.

 

Where did you get the new parts from ?

 

I have put links to your 3 posts covering the rear brake calipers and discs replacement / to use loctite or not / brake bleeding in the pinned post in the Problems and Fixes section on Removal of Rear Brake Calipers since they may help others.