I had a go at renovating the Brembo calipers on my R100RS...here's the pictorial.
Parts in ukp fr M'bins...
16.50 x 2
19.50 x 2
Remove the calipers from the bike, then split the calipers by removing the two bolts.
I'm lucky enough to have access to disposable, single use only surgical grade procedure towels. They're lint free and make a great rag to use to wipe bits clean.
I should've cleaned it much better....
Compressed air can also be used to force them out, but this is very easy and won't damage the piston lip if you're careful. Just lever them up. If the piston won't budge, then try the compressed air I suppose. In the past, I've resorted to whacking the caliper half against a block of wood to knock the piston out, when the air didn't work. In that case it did dislodge the piston enough to make the removal easier.
The mark is easy to clean up with some 1600 wet and dry, lightly lapped. I did replace the front caliper pistons with new ones, and used the best pair of the six used pistons I had for the rear caliper. I also lapped carefully around the piston bore ensuring it was as smooth as smooth could be. Not to much, just enough to clean it up.
Remove the wiper ring, use a toothpick to lever it out as it won't damage the inner surface of the bore or the recess for the rubber wiper ring.
Once the wiper ring is out, give the caliper another meticulous clean, flushing the fluid passage, wiping inside the ring recess, cleaning the o-ring recess etc. Then, use a little brake grease to lube the wiper ring, and reinstall. As you can see, I've used the pbr rubber grease as recommended by the local airhead BM Motorcycles shop here in Ringwood, Victoria. There are other products. I lightly coated the pistons to reinstall them too, but brake fluid would also work there.
The real thing..
Just push the piston back in with your fingers, then reinstall the piston seals. Coat the piston seals with the rubber grease too. It helps to preserve them, keeping them supple. As it's a specialist brake grease, it doesn't melt and won't contaminate the discs. I just rubbed it onto the seal, coating it, not a thick goopy cover, more a light smearing.
Now, same treatment to the o-ring...then place it into it's recess at the fluid passage hole. This picture shows too much...it was cleaned up more before bolting it together.
I then added the bolts and aligned them to the lower half, o-ring in place, then carefully tightened it all up, ensuring the o-ring stayed in place. edit 18/7:Snobum suggested to torque the bolts on the Brembo caliper to 22 Foot-pounds. So far, he's the only one that's written any torque value that I can find.
Back on the bike and then to prime with brake fluid.
I find the retrograde technique quickest. That uses a 50ml syringe with some tubing attached to the bleed nipple.
The brake fluid reservoir has its lid removed and most old fluid is removed previously. That way spillage and paint damage is avoided. Then I carefully flush the brake fluid up into the caliper and fill the reservoir from the bottom end. Once a bit has gone in, have a look in the base of the reservoir for fine contaminants and remove it before proceeding.
Once filled correctly, pump the brake lever carefully to ensure you're happy. Lid back on, pump the lever....go for a ride, careful at first until you're confident it's all good.
Hand model: me. Photographer: me.
