I was coming back from a ride with my daughter today and didnt figure it out right away but my front brake was fading, I was glad to find out just before we got back home. Now there is nothing, no pressure, no leaks, proper fluid level, everything seems perfect. I am thinking master cylinder piston/cups have failed but I have never seen a master work great one minute then fried the next. Am I missing something........ anti dive :wacko2:
Sounds like it's time to take a look see. Weird scenario for sure :unknown:
Quote from: gumby302ho on August 28, 2014, 08:02:15 PM
I was coming back from a ride with my daughter today and didnt figure it out right away but my front brake was fading, I was glad to find out just before we got back home. Now there is nothing, no pressure, no leaks, proper fluid level, everything seems perfect. I am thinking master cylinder piston/cups have failed but I have never seen a master work great one minute then fried the next. Am I missing something........ anti dive :wacko2:
M/C's can fail internally. That is, no external leaks and full of fluid.
Noel
I have never had one apart, but could the anti dive be leaking internally?
Quote from: the fan on August 29, 2014, 05:03:45 AMI have never had one apart, but could the anti dive be leaking internally?
The Fan,
I have. The brake fluid would then be going into the front forks, but only in droplets, not the total loss of brake pressure that the OP has reported. If a master cylinder seal fails, it can be all at once, as reported. The most likely cause would be some grit in the brake fluid, causing a leak in the same way that front fork seals can leak, caused by dirt.
A MC in otherwise good condition might be rebuilt with new seals at low cost, or if no seal kits are available, there are many options for a new replacement.
Cheers,
Red
It could be the pistons have pushed back into the bore, if you had a steering bump and caused a rotor wobble. If it pumped back up, that was probably the problem. Otherwise, I'd guess MC, as others have.
My 2ยข