Rear Brake Failure

Yesterday I was out practicing my slow speed handling, and I was giving the rear brake a severe workout for about 10-15 minutes. I know the pads must've been about as hot as they ever get. I also know I need new rear pads (they're in the mail.) However, pretty suddenly, I had basically no rear brakes. The pedal could be pushed fairly easily all the way to the bottom, with no noticeable braking happening. I didn't see any leaks... couldn't really tell what happened. So I rode it home and parked it for the night.

Today I went out and checked things over. No leaks, the the fluid is at the high mark. Plus the brakes were catching very well as I rocked it back and forth. As I started down the street, I tested 'em and could lock up the rear wheel. Took a longer ride... completely back to normal. Again, I obviously could use new pads, but even so, what would've caused that temporary condition?

I used to loose rear brakes on real hard rides in the twisties,Im sure there are better brake pads out there that will fix that problem :wink:
Also old brake fluid will cause it :wink:

I had that on my Bonnie, I put it down to boiling brake fluid, must lose its hydraulic powers when too hot

I just copied and pasted this from this link; it's long, geeky and technical, kinda like my JOHNSON but it's worth reading if you ever experience brake fade. http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml

Brake fluid is possibly the single most neglected component of the automobile. Most high performance drivers check their tire pressures and change their engine oil at frequent intervals. Virtually no one (including me) ever changes the brake fluid in their street car - or even bleeds the brakes. WRONG!

The function of brake fluid is to provide an incompressible medium to transmit the driver’s foot pressure on the brake pedal through the master cylinder(s) to the calipers in order to clamp the friction material against the discs. The foot pressure is multiplied by the mechanical pedal ratio and the hydraulic ratio of the master cylinders, booster (if used) and caliper piston(s).

This is a simple concept. When fresh, all brake fluids are virtually incompressible and the system works as well as its mechanical and hydraulic design allows. There are, however significant problems. Overheated brake fluid can (and will) boil in the caliper. Boiling produces gas bubbles within any boiling fluid. Gas is compressible so boiling brake fluid leads to a “softâ€Â

Is your brake line routed too near your exhaust?

This would assist the fluid to boil.

On hard runs the standard pads would fade bad as they got too hot , changed mine to HH pads , always a lot better hot or cold