Brake questions

[devo]

I've got a '99 Funduro and am wondering if I have rear brake problems. The brake works fine, but whenever I stop the rear disk is hot, pretty much too hot to touch. The pads are in good shape, and I have read that they should be in contact with the disk, even when not braking to keep crap from getting in there. The piston is retracting as it should, but I find I can move the outboard pad outward a little when I pull on it and it makes a little click. Once I've done this, the rear wheel does seem to turn a bit easier. If I give the rear tire a good shove on the centerstand, it will make one maybe two revolutions before stopping. Any ideas? Is this normal? I wouldn't worry about it, but my front disk never heats up as far as I can tell and the front wheel spins much more easily. The disc is not scored or warped. Thanks for any help!

[PacWestGS]

Is your rear wheel straight? Did you or someone else adjust your chain recently? How long ago did you change your brake fluid.

How many miles? It may be time for a caliper rebuild...

Were you riding off-road and struck something rather hard, hard enough to knock the alignment off?

Just ideas

Doc

[devo]

Wheel's straight, pads and fluid are fine. I removed the pads to clean them up and noticed that both Clymer and Max BMW show a little clip thingy at the front of the caliper where the pads nest. Mine has no such clip, just recessed slots that the pad plates slide into. Any ideas on this? Oh yeah, I also spun the wheel with the pads out and it didn't seem to spin any easier, so maybe everything is the way it should be. I'd just like to know if other owners have ever checked the heat on their rotor after a ride? I mean am I obsessing about this or what?

[PacWestGS]

Devo, you may be obsessing.

Brakes can get pretty hot, a couple hundred degrees hot under normal use, and even hotter under extreme use. The pads are "always" in contact with the rotors, but should just be dragging enough to keep debris out.

If you are unconsciously dragging your rear brake it could get pretty hot and result in a too hot to touch condition. If the brake fluid looks good (coming out of the bleeder valve, i.e., it's not real dark, but slightly darker than what's still in the reservoir), you are probably OK.

Brake fluids have different boiling temperatures (off the top of my head right now) around 470 degrees Fahrenheit.

However, if it's getting "hot" and you are not even using it, just going down the road. I'd have someone look at it, and make sure your caliper pistons aren't sticking.

JMHO
OMMV

Doc

[PUDGYPAINTGUY]

http://faq.f650.com/FAQs/BrakeQuestionsMiscFAQ.htm

Devo check this link out. This site has all you would ever want to know about these great bikes. Hope it helps.

[GregFeeler]

Wheel's straight, pads and fluid are fine. I removed the pads to clean them up and noticed that both Clymer and Max BMW show a little clip thingy at the front of the caliper where the pads nest. Mine has no such clip, just recessed slots that the pad plates slide into. Any ideas on this? Oh yeah, I also spun the wheel with the pads out and it didn't seem to spin any easier, so maybe everything is the way it should be. I'd just like to know if other owners have ever checked the heat on their rotor after a ride? I mean am I obsessing about this or what?


If you want to add some data to your investigation, invest in an infrared thermometer (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93984). Check both front and rear rotors cold, then go for a ride and try to use moderate and blanced braking. Then check them to see for front/read temp. differences. They should be relatively close with what rise you see mostly due to the pads dragging (the less braking you can use the better on the test ride). If you know anyone else with an F650 this gizmo will let you do some interesting A/B tests.

I'm finding this thermometer very useful for monitoring changes in tire temps as a function of different inflation pressures.

[devo]

Okay, first let me say thanks to all who offered advice. After reading your responses, reading every single word relating to brakes on F650.com and and Clymer manual and doing every diagnostic, it occurred to me to do the simplest possible thing. On the top of the rear brake caliper is an "anti-rattle" leaf spring that holds each pad stationary, but I think this spring was putting so much pressure on the pads that they would not slide on the retainer when the brake was released. I BATHED everything in brake cleaner, then blew it out, put a little moly on the tops of the pads and the cleaned up retainer and reassembled. I don't think I'm getting much drag now. If I stay off the brake, the disc stays cool as it should. My theory is that there was crud under the leaf spring which wasn't allowing it to compress completely. Hope this little exercise is of help to someone else!