Braking help please!

Hey guys, so I was out at Big Horn for practice Sunday night. After my warm up laps I cam into the pits, changed out my sweat shirt for a jersey, and tightend up my boots. When I went back out, a half lap later my brakes just went out. No compression on my brakes at all. The pads are fine and so is the caliper assessembly. I checked the brake line, in perfect condition. Not blocked what so ever and no leaks. SO it must be the fluid resavoir that connects the rear brake pedal to the line and sends the brake fluid to the calipers. I drained the fluid and the fluid is NOT getting to the line. I blew it out with an air compresser and nothing. I filled the cap where the resavior glass is, nothing, and filled it were the brake line hooks in. I don't know if I was spilling the fluid or if it was leaking out the bottom. I really don't know, so I think I will try filling it in there again tomarrow. I really want to know what you guys think is the problem. Thanks for all your help in advance.
 
Slightly, but my brakes have no compression, like there's no fluid in them. My dad brought this up, I never checked the seals behind the caliper, EVER. My claiper doesn't move when I hit the brakes either. I plan on putting everything back tomarrow, pulling off my caliper assembly, pulling out the seals and checking them. I bet there is something going on back there. I have been having trouble with my brakes since I got hit back in November. I bet my brakes finally just went because of that.
 
Ok, when you mean bent, how bent? Does the disc touch part of the caliper? I was racing one time, some guy was going backwards on the course. hit head on and i bend my disc to where there was no compression because the pads couldn't come in contact with the disc.
 
Ok, when you mean bent, how bent? Does the disc touch part of the caliper? I was racing one time, some guy was going backwards on the course. hit head on and i bend my disc to where there was no compression because the pads couldn't come in contact with the disc.
thats true... but hes not getting fluid through the lines.... you should get through the lines if you pull the whole line off the caliper
 
thats true... but hes not getting fluid through the lines.... you should get through the lines if you pull the whole line off the caliper
OK, I was thinking it could be the master cylinder aswell. Could the seal be bad? But wouldn't you notice brake fluid leaking out?:noidea:
 
What happens when you try bleeding the line? If there is no air in the line and no hydraulic pressure at all, then I would say the problem is the master cylinder.
 
What happens when you try bleeding the line? If there is no air in the line and no hydraulic pressure at all, then I would say the problem is the master cylinder.
Well my guess is the seals. Heres my logic. There must be an air leak, probably at the master caliper. Because of the air leak, being right there, my bike can't pull fluids through the line, making me think it was the resivor because I would fill it and it wouldn't move through. So if I fix the air leak, then I will get a pressure and it will allow me to pull the brake fluid through the lines. Good logic? Bad logic?
 
if you unbolt the line off the caliper.... fill the resvoir with fluid and pump the brakes... does fluid come out of the line?.....if no....... are you sure the brake lever is connected to the master cylinder??
 
if you unbolt the line off the caliper.... fill the resvoir with fluid and pump the brakes... does fluid come out of the line?.....if no....... are you sure the brake lever is connected to the master cylinder??
It did a little before I bled them. Now they don't, I don't think. What do you mean by that? Do you mean is the line hooked up? I have to fill it again, put it all back together and give it a shot again, with the line hooked up and without.
 
Well my guess is the seals. Heres my logic. There must be an air leak, probably at the master caliper. Because of the air leak, being right there, my bike can't pull fluids through the line, making me think it was the resivor because I would fill it and it wouldn't move through. So if I fix the air leak, then I will get a pressure and it will allow me to pull the brake fluid through the lines. Good logic? Bad logic?
I'm :confused: If you mean master cylinder( where the fluid reservoir is), then good logic. Although, actually, the fluid is pushed through the lines.
If you mean the rear caliper, then bad logic. I think a bad seal in the caliper would show up as leaking fluid.
Air in the line would also cause a loss of braking. This has happened to me more than once on different bikes. I don't know how the air entered the system to begin with, but after a bleeding the problem was solved and didn't come back. Try bleeding the line. If no "pfftt" of air or squirt of fluid comes out of the bleeder valve then either the master cylinder is not pumping or there might be a pinched or otherwise blocked line.
 
I just installed new line, brake handle and put fresh fluid in my wifes bike and had an issue with the air in the line from being new. It took quite awhile to get it bled out. I had to prime the line then adjust the brake handle to make sure the push/pull or draw pump action was working correctly in the master cylinder. What I mean is, if you have your brake adjustment to far in on the master cylinder(this happens when you adjust to make up for worn pads) you won't get the right amount of push or pull from the plunger that enters the master cylinder. Basically what happens is the O'ring is already past the valve inlet inside the Master cylinder and when you hit the brake there is no pump or draw circulation.
 
Ok here it goes. I had to rebuild the bleeder valve, so I bored it out to 1/4 inch and ground down a screw, put a beveled edge on it and wrapped it with teflon tape. It went together nice an tight. Finally I tore the whole brake system down and cleaned it up, put it together, lubed the seals, and filled it up with braking fluid. It's slowly leeching in now, the level dropped an inch within 20 minutes so I think it's gonna work. I'll shit if it doesn't.
 
Ok here it goes. I had to rebuild the bleeder valve, so I bored it out to 1/4 inch and ground down a screw, put a beveled edge on it and wrapped it with teflon tape. It went together nice an tight. Finally I tore the whole brake system down and cleaned it up, put it together, lubed the seals, and filled it up with braking fluid. It's slowly leeching in now, the level dropped an inch within 20 minutes so I think it's gonna work. I'll shit if it doesn't.

Sounds like you're a Disney Engineer. :shocked:

First, teflon tape is for sealing tapered pipe threads. On a bleeder valve, the sealing comes from the beveled edge of the screw. To me, it sounds like you just wasted your caliper by drilling, and tapping. So now, to bleed your brakes, you have to pull the homemade screw all the way out? Good luck with all you've done, and also remind me never to buy a bike from you. :P

Edit: Also, not to be a negative Nancy, I'll shit if it does work. Please keep us informed. :noidea:
 
Top