rear brake rebuild failed

I just rebuilt my rear master because there was no fluid left in it after my bike sat for 22 years. I blead the system and I got all the air out.The brakes seemed to work on the center stand, But when i took it for a test drive the brakes don't work under load.Is this a symtom of air in the lines still?

try bleeding brakes some more.

the master cyl is a pian in the butt to get all the air out, still messing with mine after a rebuild

if you keep bleeding the rear brake and have no luck, you might want to take a good look at the rear brakehose if it has been setting that long.

I put a new stainless line on allready. I blead them again today.I got some more air out but there still not up to par.

Waitaminute. Just a question, and I am sure that you have addressed it, but what rear pads are you using? The originals, or a newer set? Could maybe, just maybe, need a break in on new pads, or maybe knocking the glaze off of the rotor might help.

Just a couple of thoughts, I didn't see this addressed in the previous posts.

Louie

mark1122 wrote:

I put a new stainless line on allready. I blead them again today.I got some more air out but there still not up to par.

Yep, this has happened to me. I now swear by "speed bleeders", but I still am not the best at getting all the air out the first time.

My current method involved alot of tapping (gently, of course) and waiting. Sometimes, when I *think* I have it right (but don't), I take it for a spin around the block. When I come back, more air comes out.

Oh, and I recently have changed to a "squeeze like crazy" method for bleeding. Fast and furious squeezing seems to get those tiny bubbles out, as they don't seem to progress with slow methodical squeezing....

I hate bleeding brakes...

:pinch:

Took me maybe 3 hours to bleed the hydraulic clutch on my zx1100. Then within 5 min went from soft as hell to bang on. My method for brakes is plastic tube over bleed nipple to jar of fluid. Pump lever moderate speed till it stiffens up then have buddy quickly crack nipple and just as quick close. This is done with me holding lever in. Ensure reservior does not go empty. A turkey baster will draw fresh fluid thru quick but have always had to resort to bleed proc. I hate bleeding hydraulic systems. Never as easy as manual makes it out to be. Long drawn out process involving lots of fluid.

GPZROX. These are old pads. what do you mean by knock the glaze off the rotors? I first tried the fast and furious method then when I didn't see any more air I whent to the pump up the preasure meathod.I'll give it another go on the weekend.

What I am thinking is the pads could have become rock hard over the years, and very possibly very smooth and slick, like a piece of glass. No bite to them.

Auto parts stores used to "turn" or "cut" rotors, grinding a small amount off of the surface to get a fresh surface for the pads to bite on. Usually this was because of grooves, but in some cases, the brakes had gotten overheated, and the surface of the rotor -ummmmm- crystalized, I guess you could say, got hard and didn't offer as good of a place for the pads to bite.

I just erased a whole tech witeup on brakes, but I would say: Get new pads. Cheap and easy, you aready have the rest of the work done: lines and m/c.
Cool?

Are you using DOT 3, 4 or 5?

dot 5. I blead them again and there working. i can lock it up now.But i would like it to be more sensitive and less travel on the peddle.