dravyck Posted March 21, 2015 Share Posted March 21, 2015 So after my crash detailed here http://fz07.org/thread/1850/crashed-fix-bent-forks I immediately noticed my front brake was not really working. I figured I got some air in the lines when it was on it's side so I'd just bleed it after I got the forks fixed. Well I've had my bike for a little over a week and I'm gonna need some help. I've bled the old fashioned way by squeezing the lever, cracking the caliper, squeeze the lever all the way, close the caliper and release the lever. Refilling fluid as needed. No noticeable air bubbles were coming out. So I switched to a hand vacuum. Hooked up the line, built up pressure, cracked the caliper and here comes the air bubbles. Good, but the problem is that I went through a bottle of brake fluid. Theres no way theres that much air in the line, so to double check myself I went on to technique 3. I grabbed some 50cc syringes from tractor supply and injected brake fluid into the calipers. Zero air bubbles came out of the fluid reservoir. But pulling on the syringe I got the same rush of air bubbles as I did with the hand vacuum. I have initial braking power but the brakes eventually go completely flat, the lever closes all the way to the bar and there is zero braking power. If I pump the lever I get braking power, but any sort of steady braking and the brakes go completely flat like before. So I thought maybe a master cylinder problem. I pulled it out and it looks fine. TLDR Bled the brakes: old fashioned way, pump, and syringes. Master Cylinder looks okay No leaks in the system from what I can tell Have braking power for a second and they fizzle out, lever goes all the way to the bar and left with zero braking power, pumping the lever resets the brakes. No clue what to do at this point. I've gone through 2 1/2 bottles of dot4, tried everything I can think of. 82 Yamaha XJ550 Maxim Black (Passed Away) 15 Yamaha FZ-07 White Link to comment Share on other sites More sharing options...
YZEtc Posted March 21, 2015 Share Posted March 21, 2015 The lever eventually comes to the handlebar while riding the bike? Link to comment Share on other sites More sharing options...
dravyck Posted March 21, 2015 Author Share Posted March 21, 2015 Yeah. I just isolated the master cylinder with a pair of vice grips to the brake line. Same issue. So I went ahead and ordered a master cylinder rebuild kit. Had to order online, the local dealership doesn't have them. 82 Yamaha XJ550 Maxim Black (Passed Away) 15 Yamaha FZ-07 White Link to comment Share on other sites More sharing options...
YZEtc Posted March 21, 2015 Share Posted March 21, 2015 OK. Good luck with it, and let us know how it works. Link to comment Share on other sites More sharing options...
rick Posted March 21, 2015 Share Posted March 21, 2015 Yeah. I just isolated the master cylinder with a pair of vice grips to the brake line. Same issue. So I went ahead and ordered a master cylinder rebuild kit. Had to order online, the local dealership doesn't have them. Am I reading this correctly - you pinched off the brake line with the vice grips? If so, I'd replace that hose as well. When you go to bleed this system, keep in mind that the loop of hose that goes over top of the wheel will be a perfect place for a bubble to get caught. You might have to lift one caliper up so that hose is straight. Have you pulled the piston out of the cylinder? Do the seals still look OK? Was the brake lever damaged in the crash? I'm afraid yer gonna need more than a seal kit. Link to comment Share on other sites More sharing options...
Guest Ralph Posted March 21, 2015 Share Posted March 21, 2015 I know it sounds unlikely after the mole grip test but are you sure the discs are running true, if they were bent during the off and are wobbling slightly they could be knocking the pads back. Link to comment Share on other sites More sharing options...
dravyck Posted March 24, 2015 Author Share Posted March 24, 2015 I've completely pulled the calipers off the bike and inspected each one and the hoses, as well as pulling out the master cylinder, it looks fine. I thought that maybe one of the discs were bent as well but I have the brake problem while not moving as well. 82 Yamaha XJ550 Maxim Black (Passed Away) 15 Yamaha FZ-07 White Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.