UVG Posted July 20, 2015 Posted July 20, 2015 Hi GuysI’m looking for a second opinion...or a third or fourth opinionI am replacing the rear calliper on my C5 (as I have nice wedge shaped brake pads)I’ve read the different views on a couple of forums about the corrosion created by the different metals and the instructions in the Haynes Manual to use a Loctite sealant between the calliper and the swinging armI read that some people have used a thick plastic to keep the two metals apart and I thought that sounded like a good idea but the Haynes Manual says the sealant has to be able to cope with 2000C that’s a bit toastie for a bit of polytheneSo I bought a sheet of 0.8mm PTFE because I know its tough stuff its hard wearing and has a melting point in excess of 2000CSo that’s the background here’s my problem and the bit I need some opinions on:The calliper stops the car because it cannot move and it grabs hold of the disc which is going round at an alarming rate. The shear forces must be quite large so the calliper needs to be securely fastened to the swinging armSo what does the holding? Is it just the shear strength of the bolts or does the friction (that is created by the tension in the bolts) between the calliper and the swinging arm play a major role because I’m about to put one of the slipperiest substance known to man in between themSo I still think the layer of PTFE will do a good job of reducing the corrosion but that’s not a lot of use if I rip the callipers off the swinging armsSo your opinions please....CheersUVG Quote
Johndouglas Posted July 21, 2015 Posted July 21, 2015 All I've ever done is clean them up and coat them with copper slip. Quote
paul.h Posted July 21, 2015 Posted July 21, 2015 Same as John on our C5s, only ever used copper grease but it does not do a permanent job of stopping the corrosion and needs repeating every couple of years but the brakes need cleaning anyway so it is not much more effort to do. There is a pinned topic on the C5 brakes you can read http://www.citroen-owners-club.co.uk/citroen/forum/97-problems-and-fixes-c5/. I think I read that coastline has used polythene but it will be a lot thinner than the 0.8 mm PTFE, the thickness of which you may find is a problem and you may need to keep tightening the bolts as it gradually thins so I could not recommend using the PTFE. You may even find trying to do the caliper bolts up to the 70 Nm will cause the PTFE to be extruded and thinned. For calipers that originally used loctite along the bolts, to seal the caliper/arm joint, Citroen procedures are:ESSENTIAL : Coat the surface between the brake caliper and the rear arm with FORMAJOINT 510 sealing product. Quote
UVG Posted July 21, 2015 Author Posted July 21, 2015 hi guysthanks for the suggestionsI posted the same problem on the French car forum and got some interesting suggestionsI have gone off the idea of using the PTFE I have ordered the Loctite 510 I think I'll just do as Citroen suggestthe cars 10yrs old and its lasted till now if I do it again and it lasts another 10 I cannot really complainwell I could but no one would listen :D Quote
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