Rear brake problem?

[austin03]

I was riding my Suzuki DRZ250 in tight woods and then my rear brake wouldn't work after riding for fifteen minutes! My rear brake is a hydraulic disk. My rear brake operated like it had no brake fluid in it. The brake lever would extend the full travel. I didn't ride the brakes. The brake caliper was real hot. After five minutes, the rear brake would operate normally. I checked the rear brake reservoir and it was full. I bled the brakes and the reservoir was between full and low. Went back out and the same thing happened. The brake fluid is brownish color. My friend thinks a brake fluid change would cure the problem. Anybody have any idea what happened.

[georgestr]

Check the pads, then change the fluid. Worn pads could overheat the fluid.

[austin03]

Looking at the caliper, the pads look a little over an 1/8" of thickness. What thickness does a new pad have? I haven't disassembled the rear caliper yet.

[knuklehead]

I add a second backing plate from an old set to insulate the caliper from the heat better[ inbetween the new pad and piston] with out it i can fade mine till they don't work at all till they cool off, if your fluid is brown you should bled some new in.

[hodgkins]

new pads are approx 1/4 thick.Iv'e run a few sets right down to paper thin and never boiled the fluid.are you wearing new boots or perhaps this is a new bike to you.you might be dragging the rear brakes and not realize it.but yes flush all of the fluid and replace with a good dot4 fluid.don't run some cheesy kragen brand.

[FLboy]

Yeah.... what they said. Really, get new pads and change the fluid. It sounds like the fluid is burnt. Make sure your rear break is releasing also. Could it be that it is not releasing all the way and there is still friction? That will heat it up real quick.. If that is the case, you'll need to to check out the calipers real well. They could be sticking?

[StevePSD]

Your fluid is brown because it has moisture in it and got hot....water boils at a lower temp than your brake fluid....when it boils you get gas bubbles in your line....which causes a mushy brake...then no brake....lever/pedal goes all the way to be stop without any resistance.

Change your fluid with DOT4 rated fluid from a sealed container. DOT4 has a higher boiling point than DOT3 fluid and is fully comptable. Make sure the fluid comes from a sealed container....brake fluid is hygroscopic. This means for brake fluid, that the fluid will absorb moisture from the air. I flush the brake fluid in all my vehicles every two years.

[austin03]

I really appreciate everybody's recomendations and fix.

[FLboy]

Your fluid is brown because it has moisture in it and got hot....water boils at a lower temp than your brake fluid....when it boils you get gas bubbles in your line....which causes a mushy brake...then no brake....lever/pedal goes all the way to be stop without any resistance.

Change your fluid with DOT4 rated fluid from a sealed container. DOT4 has a higher boiling point than DOT3 fluid and is fully comptable. Make sure the fluid comes from a sealed container....brake fluid is hygroscopic. This means for brake fluid, that the fluid will absorb moisture from the air. I flush the brake fluid in all my vehicles every two years.

I learned something there. Thanks!