Cant get all the air out of my front brakes

[stian]

Originally Posted by adddy

i to have been going round in circles bleeding.. with new seals top & bottom & hose,
iv been squeezing, pumping, vacing, pushing,taping,elevating,dangling,rotating & pushing the pistons independently & only see odd occasional bubbles , some tinny or regular size ..but only getting the leaver to be firm... & not hard... eg two fingers will still pull to my knuckles have been over a month on this dilemma ..nissin calliper + lever

Bad seals in either cal or pump.

if you have ever got a new bike, and try to bleed the brakes.. takes 1-3 seconds. Ive got problems with the seals on my nissin myself.

[adddy]

brake fade is some thing to do with heat building up too much & glazing over the pad materiel, or boiling the brake fluid that may of absorbed H2o, then it expands as steam...

[adddy]

Originally Posted by andykr87

My front brakes on my 13 have been margianal ever since i bought the bike. Ive vacuum bled them and back bled them and they still have air and horrible lever. At the little brown jug last weekend i was blowing turns and yesterday i passed a guy, grabbed a handfull of throttle and pulled in the front lever only to not be able to release the throttle and i waded up in a tree. Now im laid up with a severly swollen knee and ankle. Asteriks braces saved my knee too. I read about the rmz banjo swap and a rmz lever will swap too for better feel. Is there anything else i can do? Sintered pads sound like a option too. I spent one night pushing the caliper in the tickling the lever on the master cylinder with the handle bars turned left to get it above the brake line, air just kept coming out, looked like carbonation from a soda sometimes. Im going to try and race the national enduro this weekend if my leg heals but not if my brakes are this shitty. Any ideas of suggestions would be awesome. Thanks guys

if you had the bike from new then its a factory problem ?..if 2nd hand & the system had been open for any reason ? new hose or popped a piston by mistake through cleaning then its very difficult or maybe imposable to bleed entirely by usual methods ... but popping the pistons & reassembling in a suitable container of brake fluid (striped of the rails no pads) then toping up MC may be the quickest method to this air trap conundrum..this is the path i chose today with mine & i can say im definitely seeing improved feel bit by patient bit & will resume removing air bubbles tomorrow by more lever angled flick/pumping the MC then compressing the pads (reinstalled) in pushing fluid up & air to the MC. calliper off & lower at all times..you will need a syringe to constantly + & - the fluid level in the MC keep repeating with the pads in & modulate the fluid level until Elvis has left the building !

[adddy]

[andykr87]

So submerge the caliper in fluid, and reinstall the pistons submerged? Makes since. Then pour fluid in the MC to fill the system? Or back bleed it with a syringe? Im going to find a newer rmz or similar MC and shit can the black one. I have a feeling its part of the problem.

[stian]

Originally Posted by andykr87

So submerge the caliper in fluid, and reinstall the pistons submerged? Makes since. Then pour fluid in the MC to fill the system? Or back bleed it with a syringe? Im going to find a newer rmz or similar MC and shit can the black one. I have a feeling its part of the problem.

Its not that dangerous. Just swap the seals in the caliper. Air isnt so dangerous.
Take a hose that fits, take a canister/syringe and fill it FROM the calipper TO the pump. When things are flowing over at the top, close the bleedscrew, and bleed as usual.

Problemo solved.

[adddy]

o well i thought there was gunna be a fully sorted front brake today...no better after seeing plenty of trapped air rise through MC

[Elvis74]

Have you checked the piston and the I-rings in the pump? I had the same with my clutch. After putting a repair kit in, it worked.

[Neil E.]

Originally Posted by Elvis74

Have you checked the piston and the I-rings in the pump? I had the same with my clutch. After putting a repair kit in, it worked.

Agreed, if you have to fight it too much, it's time for a repair kit in the master cyl.

The only way I could get mine to be 100%, was to put a custom plate with fitting over the master reservoir opening, and apply vacuum for half an hour. This was using an electric vacuum pump.

[barossi73]

Pretty sure he said he had new seals above,if any of the seals were allowing fluid to bypass there would be weeping at the lever/piston or around the caliper pistons,or bubbling in the master during the stroke.(a little at the very beginning of the stroke is not unheard of tho until the seal moves past the outlet hole).new seals can be quite 'dry' and should be greased with rubber grease when fitted,caliper pistons should move in and out with moderate pressure.my best guess in no particular order would be -sticky piston/seal in caliper,faulty seal/bore in master,or....air still.might be time for a new master if you're sure of all the rest.agree with comment above-it should usually be a fairly painless process tho.old british landrovers are on the other hand an absolute nightmare...