Rear Brake bleeding. What am I doing wrong?

[petevtwin650]

Stripped rear caliper, cleaned everything up and put in new seals. Replaced the seals and plunger in the rear master cylinder. Bled the new fluid through. Problem is I can't get a solid pedal. Too much free play before the brake brakes. But, even the smallest of pedal travel translates to movement of the pistons without the pads. Seems like the pistons retract too much and use a lot of the pedal movement to take up the free play. Got a braided hose too.

Any suggestions?

[BILLY]

You might still have some air in there! Mine did the same to so I bought a mityvac bled it again and it was perfect.

[Biker Biggles]

There are two bleed nipples on the curvy rear caliper.Are you bleeding both of them?

[petevtwin650]

Cheers Billy. I've got a Mityvac too. But TBH I don't get good results from using it. I did use it for reverse bleeding the system. At least it drew the fluid through.

Maybe I'm just doomed. DOOMED I tells ya!

Just saw your post BB. Yep, using both of em.

[Richie]

have you cracked open the first banjo bolt (brake hose start) and blead there first, then gone to the rear bleed nipples.

or is that the first bleed nipple point ?
I had the same problem with my pointy.

[embee]

Sounds a bit like the seals might be sticking to the pistons a bit too much, giving the excessive pad/disc clearance you describe.

I like to smear a very light film of red rubber grease on the piston before fitting. This tends to let them slide easily on first fitting and then they'll settle to the normal state after a little while as the grease eases out of the area where the seals contact.

You should get a perfect bleed with a mityvac, I prefer the method of pumping some vacuum into the canister then ease the nipple open a touch to let the fluid flow, rather than trying to pump with the nipple open already, just personal preference.

[northwind]

I've got a mityvac but I'm a total convert to the Big Ass Syringe method, I find it way faster than the Mityvac since you can push fluid up from the calipers rather than sucking it through from the res- bubbles naturally want to go up after all. So I push a load through from both sides, then if I'm not happy push it back down and into the syringe with the lever, then back up and that's pretty much it.

[ejohnh]

Sounds like nothing to do with the bleeding if there is excessive piston movement. The pads should just clear back from the disk I thought - like on a car.

when you bleed do you see bubble free brake fluid coming out?

I will need to renew all my brake pads soon and I am hoping to use a tube with a non return valve that I used on my car.

[Lissa]

Pete says thanks for your replies:D

He'd post himself, but he's busy bleeding the brakes before our run today.

Big thanks to The Wasp, who joined us at Mallory yesterday, for his suggestion of hanging the rear caliper up high over-night to allow the air to rise to the top......................seems to have done the job:D

Thanks Steve..................and we'll see you and Tianne later:D