1 Rear brake question 85 K100RS Mon Apr 20, 2015 11:07 pm
diversity48
active member
After bleeding the front brakes succesfully, I tried bleeding the rear. Seems that I have a bad Master cylinder, here is what it does: Removed most of the fluid from the reservoir, filled it with fresh fluid, and proceeded to drain the caliper using a "Mity-Vac" which I have used on other bikes and on the front calipers with complete success. Only could get a few drops into the canister of the mity-vac at first, and after pumping it several times, ended up with only a very small amount of fluid there...possibly 1/2" or so in the bottom of the canister. Tried bleeding the old fashioned way...pumping the pedal, and after MANY pumps, probably 100-150 or so, finally got the rear brake to function, but just barely. Now I have very little rear brake power. After reading related posts on the subject, I'm thinking that it may be the master cylinder. With these symptoms, what would your opinion be? I have not taken the caliper off, but I'm thinking that even with leaky seals, the caliper should at least be kicking out some fluid from my efforts. Just need some educated guesses here...what do you think?