Brake Caliper fun... Rebuilding rear brake caliper/bleeding... HELP!

Hey All,

Doesn't everything go at once? It seems like its that time of the year... I'm a noob at motorcycle maintenance... especially with these linked brakes that seem quite complex...

I have been experiancing brake drag since I installed my Galfer rear pads a few weeks ago... they were considerably thicker than the pads that were left on the bike... The pistons on the calipers pushed back in tough but I thought not much of it since I always used a C-clamp on car calipers... I put the brakes together and they were a little tight, but I figured after a ride or so they would loosen up after being broken in... wrong.

I pulled everything apart tonight... In the rear caliper, the 2 outer pistons move freely with the rear brake pedal as they should. I gather that the center larger piston should be activated by the front master cylinder on the caliper on the chain side... And it is... but boy I have to pump it 50 times to get the piston 1/2 way out... And then it takes all of my might (with a few rags over my thumb) to push the cylinder back in...

I gather this is not normal. Correct?

So I'm thinking that the rear caliper needs a rebuild...

According to what the manual seems to say... If I pull the rear caliper and rebuild it... I can put it back on the bike and just bleed the rear line... Correct?

Any guidance/advice would be appreciated before I dive into this one...

~mikeym

hmm... nobody?

Well I suppose I'm going to pull the center piston... put new seals and piston in... attempt to re-bleed and hopefully that fixes it...

~mikeym

[image: View Post]mikeym, on 17 May 2010 - 06:58 PM, said:

hmm... nobody?

Well I suppose I'm going to pull the center piston... put new seals and piston in... attempt to re-bleed and hopefully that fixes it...

~mikeym



Wow! I'm have the exact same problem. Is there any wisdom you could share? Did you eventually get it worked out?

I'm not the best w/ that whole LBS stuff, but that said.... IF it's just the middle pot on the rear brake sticking, then I'd start w/ flushing the hyd. fluid circuit that runs from the secondary master cyl (I think that's on the left side? front brake), through the proportional control valve, to the rear center.. if you want to test the piston on the rear brake, loosen the hose from the PCV to the rear, and see if it's easier to move the piston then...mind you, you'll probably need to bleed it then, and make sure to contain the fluids... if it doesn't move freely w/ the hose off, then rebuild that piston.. if it does, then you need to start looking at the PCV or the secondary mast cyl as the culprit.

before you rebuild ...perform a quick bleed. open the reservoir cover before you press the brake pads/pistons in.