I just installed a new rotor, pads, and rebuild kit. I bled the brakes and they were working fine. Halfway through the ride, it locked up and the rotor was smoking. I had to loosen the banjo bolt on the caliper to release the pressure, then it was ok. 10 minutes later, the same thing. What's going on? Did I use the wrong brake fluid or something?

 

If you can release the pressure at the fitting at the master cylinder you could have a bad hose. If not there's a problem in the master cylinder.I'm not sure about the raptor but most masters use check valves and it sounds like yours is sticking if that is the case.

 

I changed the fluid to DOT4 from DOT3 and its a little better, but it still does it. I dont know about any check valve on the master cylinder. It seems to me the fluid is heating up too much and causing a pressure build up. Anyone have any ideas? I have to get off the quad every 5 minutes and turn the bolt on the caliper to relase the pressure. That's no fun!!

 

Well, I've disassembled the master cylinder and caliper and cleaned them out, installed a new braided brake line, put it all back together. Bled the system with DOT4 fluid and the same exact thing happened again. It locks up after 10 minutes use. I have to open and close the banjo bolt on the caliper to release pressure over and over again. Does anyone have ANY information as to what the problem is??? The master cylinder appears to be rebuilt properly and the caliper moves freely.

Any reply is greatly appreciated.

Thanks.

 

try a different master.jmo

 

I know you said you have new parts...but are you sure that new rotor is strait? Do you still have a stock swing-arm? I'd guess that the thing is dragging(yah no crap huh?), did you mount the caliper back up correctly? Are the pads on one side of the rotor worse than the others. Are you using automotive brake fluid or the high temp stuff(you should be).

 

if its all new parts take them back and make them exchange them.

 

I checked the rotor with a straight edge. It's straight. And yes, I've got the stock swingarm. I checked the pads and it looks like the wear is uneven or slanted is a better description. The floating bolts that allow the caliper to move as the pads wear seems worn. This lets the caliper wiggle while its mounted. When the brake is applied, the caliper moves slightly so its not 100% straight with the rotor causing the slanted wear. Do you think this causes excess drag, then excess heat, then boiling brake fluid, then the locked brake? I use Prestone DOT4 fluid I bought at Wal-Mart. I've seen some really high temp stuff at the auto parts store but it wasn't compatible with DOT3 & 4 fluids (think it was DOT5 maybe?). But maybe I can flush the system, reclean everything, and use the DOT5 stuff. What ya'll think?

 

I checked the floating bolts. One was a little jammed with old grease and sand. I don't know if that has anything to do with though...???

 

take the thing off,i don't use mine.