Hot rear brake

[hal]

My rear disc allways feel warm/hot after a ride, even if I didn't use it. It's time for inspection/change of pads anyhow, so guess I will see then.

[melville]

Make sure the master cylinder is returning all the way. Otherwise the wee hole that permits expansion of the brake fluid will be blocked and just a little heat can turn into a lot. This can lead to the rear brake locking up in extreme cases.

[hal]

Thanks Mel.

[Wobbly]

Make sure your OEM brake hose has not collapsed. The black flexible rubber hoses decay on the interior (where you can't see it) and collapse internally. The result is that the brakes can go ON becasue the master cylinder creates an immense amount of fluid pressure. But when the caliper goes to push back and release the brakes back to the OFF position, it simply can't muster the pressure.... so the brakes remain in the ON position.

This is very common on all motorcycle braking systems older than 5 years... especially if the fluid is not changed regularly. So I'm not "picking" on your specific model or BMW.

The way to tell is to jack the wheel off the ground and try spinning the wheel by hand. Then apply the brake and spin the wheel again. Some people spot this when they can no longer push the bike into the garage, or they notice their bike slowing as they coast downhill ! If it happens during a trip, you may need to open the bleed nipple to relieve the hydraulic pressure just to get home !

At any rate, if your bike is over 10 years old, and you're planning major brake system service anyway, you should most definitely take advantage of the down time to add new "stainless steel" brake hoses. The best ones on the market are probably from Spiegler, but there are numerous other sources. The internal hose is actually fluid resistant PTFE (Teflon) with an outer stainless braid which allows the tubing to withstand the pressure.

[hal]

Thanks Wobbly,

Changed all the brake lines to Goodridge stainlees steel a couple of years back, so that's not it.

[SteveD]

Had that happen on a 65LS once. The footpeg was loose and rested on the brake lever. It didn't pick up speed at all and I thought the diaphragm was holed!