Do I need to remove exhaust to replace rear disc on R1200GS (2005)

[AustinW]

Just done mine too. Easy peasy. A bit of heat on the bolts and they came off worryingly easily. 10mins later the new disc was on.

Part of the reason for the wear on the disc (apart from 75,000 miles) is that one of the pistons in the caliper was very stiff. It needed a clamp to get it back in but after a good scrub of the inside of the caliper with a toothbrush and wd40 and a couple of ins and outs on the piston I could just about push it back in with my thumbs. Nevertheless I am going to order a rebuild kit (if such a thing exists) and rebuild the caliper, although I may take it into the local workshop as I seem to have two left hands and a blind spot when it comes to hydraulic stuff.

Where's me women?

 

[Bendy toy]

A rear caliper seal kit costs £19.75. New rubber bellows are extra. For comparison, a front caliper kit is £60 but you do get four new pistons.

You can extract the pistons either by using the hydraulics (messy) or with a cycle tyre stirrup pump with gym ball adapter (plastic come thingy). Blow air into the hose banjo hole.

 

[AustinW]

A rear caliper seal kit costs £19.75. New rubber bellows are extra. For comparison, a front caliper kit is £60 but you do get four new pistons.

You can extract the pistons either by using the hydraulics (messy) or with a cycle tyre stirrup pump with gym ball adapter (plastic come thingy). Blow air into the hose banjo hole.

Yeah spotted the kits. The bellows seem ok, just one of the pistons a bit sticky - the piston itself could with replacing as there is a small chip on the crown of the "insert" - the face that acts on the pad. The chip doesn't seem to be on the skirt else it would be leaking, and its not. I cant seem to find new pistons after just a quick search. Brembo rear caliper on a 2011 GSA anyone??

 

[Bendy toy]

A chip on the working face of the piston should be fine. The fluid seal is about 6mm down from the top face.

Pop them out anyway, clean rub on some red rubber grease and put back. DO NOT use silicone grease - its too slippery and causes the brake to bind.

 

[MattW]

Make sure you put the new seals in the right way round - the face that bears against the piston is actually slightly wedge shaped to help the piston retract after the brake has been applied (this is assuming that they're the same as 11xx piston seals - never had to do it on my 1200).

 

[Bendy toy]

Make sure you put the new seals in the right way round - the face that bears against the piston is actually slightly wedge shaped to help the piston retract after the brake has been applied (this is assuming that they're the same as 11xx piston seals - never had to do it on my 1200).

I could see no difference on mine. Fitted one, checked the sticking out side. Took it out and replaced the other way; it looked just the same. The brakes work as they should so I suspect the seals used on 1200s are not handed.