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Re: Brakes

<<Last year the front calipers on my 1994 R1100 RS started to stick to the point where if I kept going they would get so hot as to stop the bike. They would release after the bike sat for a few minutes. I ordered a caliper rebuild kit and all seemed to be OK but now they are doing the same thing. There is a bit of drag between the pads and the rotors but not a whole lot. The bike sits all winter and I am thinking that the problem may be the master cylinder as both rotors got hot. A few days ago the bike started to slow down after less than a mile and I believe the bike would have completely stopped if I had tried to keep going and both rotors were very hot. Before ordering a master cylinder rebuild kit I would appreciate any comments or suggestions. Can you also tell me what I should order. Is it just the piston in the master cylinder or are there seals also?

You will be well served to do some research and understand exactly how your brakes work. If you are unsure, I would suggest that you get professional assistance. Brakes are "mission-critical," to paraphrase a local guy. Don't take chances to save a few bucks.

There is a fluid return hole in the master cylinder that allows excessive fluid pressure to bleed off into the reservoir when the lever is fully released. If this tiny hole is obstructed, the fluid pressure will build when the fluid heats up, causing the brakes to drag and overheat.

You need to check and clear tht littl ehole. Rebuilding the master cylinder may NOT take care of that little obstruction. Also, if the master cylinder is not LEAKINGl it does not need rebuilding.

Another possibility is that one of thbrake hoses is failed internally, acting like a one-way valve to fluid flow. This is getting pretty common on 15+ year-old R1100 models. We are seeing lots of hydraulic line leaks and failures.

Replace the brake hoses with OEM or aftermarket stainless hoses, then fluch/bleed the system. Use a tiny wire to clean out that fluid return hole, visible in the bottom of the fluid reservoir when the cap is off and the fluid drained. Use FRESH DOT4 or 3/4 brake fluid from a NEW, SEALED container. DO NOT use DOT5 fluid. If you disassemble anything, wash the parts with brake fluid only, no soaps, solvents, etc. When everything is all back together, you can clean any fluid off the OUTSIDE of theparts with warm soapy water, then rinse with clear water.

Tom Cutter
Yardley, PA
*"To get something you never had, you have to do something you never did." *