Topic: Brake issue

[53kemper]

Have a 76 750F SS.  Rebuilt the front brake.  New master cylinder, New caliper, new seals, new pads.  I bled the brake but the lever still feels soft.  Doesn't seem to get very tight.  I can slow down and the brake works but it's not very strong.  I've bled the brake and ran a full bottle of brake fluid through it to make sure there were no bubbles. Still doesn't seem to get tighter.  Any ideas?

[Kalamazoo]

Zip tie the lever to the handlebars and leave over night is one suggestion I've heard.

[53kemper]

Ok I'll try that and see if it helps. I'm guessing that it puts pressure on the system and releases any air that may be in the lines?

Thanks.

[new2novas]

are you 100 percent sure that master is for your setup....doubt thats from air if you ran that much fluid through it.....as long as the fluid ended up coming out without bubbles...(is there any specialized bleed procedure for the master on a bike as there is for a car master)

[53kemper]

It's the original set up. Just replaced everything with new parts. If the zip ties don't work I'm going to tear it down again and see if I can find anything wrong.

[BeSeeingYou]

Are you sure you got the correct rebuild kit for the 76.  I think the 77/78 kits are almost identical but there is a small difference.  I recently rebuilt my brakes and after bleeding them the first time the brakes were just ok.  The next day I bled them again and got a bit more air out.  Sometimes you can get these tiny micro bubbles and they can be hard to see.  Letting it sit overnight helps them come together into larger easier  to get out bubbles.  I think strapping the lever down does the same thing. and it also allows the bubbles to move to the highest point.  Turn you bars so the master cylinder is at it's highest point.

[lordmoonpie]

I have to say I'm at the same place and it's damn frustrating - K0 calipers, fully restored, ne seals, new pistons, stainless lines and brand new master cylinder. I've bled them 5 times now and used two litres of fluid in the process. I have zip tied the lever, tried the syringe upwards approach and even though there's no air bubble in the lines, the lever is soft. It's driving me mad!! 

[53kemper]

I haven't taken the zip tie off yet, will do that tonight.  I'm wondering if it may be the piston seals are to tight.  Has that ever been an issue for anyone?  i can't think of anything else causing the problem.

[ev0lve]

If it's any consolation - same here. SS lines, rebuilt master, new seals.

Let the pressure switch loose, tapped the lines etc etc.

Wondering if I may have the adjusters on the calipers a bit too far out at this point as I've got a bit of squeal as well or if the master is not quite right.

It's something 

[MCRider]

Somewhere, somehow, there is air in the lines or equipment. It may be a bubble stuck in the caliper. Remove it and tilt it. Pumping a lot of fluid thru it is not the proof there is no air. A firm lever is the proof.

When you pump the lever, with the bars turned so it is high, pump very slowly and watch for little stream of bubbles coming up thru the return holes. Also don't pull it to the grip.

Just all things I have tried at one time or another that have worked. Though success is often inconsistent.