Brake bleeding?

[peterreeves]

I have replaced all the components on our 1996 traveller brake system. I have bled the system three times now and still getting the peddle going flat to the floor. I have primmed the new master cylinder before fitting it to the vehicle and am getting no more air through the bleeed nipples. I notice in one of the technical articles that it can be difficult to get air out when replacing the master cylinder but I am finding it impossible - anybody out there with any tips please. many thanks. pete

[Orkney]

Something sounds very wrong there.
Assume youve kept the M/C topped up whilst bleeding - thats a very easy way to getting air back in.
Did you prime the rear pistons before you put them in?

Also golden rule and a big time saver - dont ever assume (as in the case of your new MC) that just because something is new it is working properly.

[8009STEVE]

Have you adjusted all the shoes?

[alex_holden]

Did you fill the rear brake cylinders with fluid before connecting the pipes, as if not you can get an air lock inside that's tricky to get out via normal bleeding methods.

[MoggyTech]

Good bet it is a leaking copper washer at one of the rear banjo connectors. Either that or incorrect union thread on one of the fittings.
Best to anneal the washers before fitting.

[peterreeves]

thanks for the replies - I primed the master cylinder but not the rear cylinders - will give that a go before next attempt. I am using an easy bleed pipe and on depressing brake peddle getting a really good squirt of fluid through the bleed pipe valve so the M/C seems to be working OK - I don't appear to have any leaks throught the copper washers but will check that also - cheers folks

[Orkney]

bit of a tip - pain that you have to remove the rears to prime but when you do so if poss jack the car level facing downhill before you bleed off the backs as thats the first 2 in the order of things anyway. this way any air between the MC & the T joint should hopefully be going upward by physics - make sure you dont have any upside down U kinks in your pipes that might be causing an airlock.
What i did was make sure any bends were paralell to the floorpan before bleeding - that way the air can only come out the rear end. Then shape them back carefully once bled.
it works this way and the reults are quite startling - then after the rear jack the front level and do the rest - the airs got no choice but to be excluded.

[DAVIDMCCULLOUGH]

Have you adjusted the master cylinder rod? If you have replaced the cylinder it may need some clearance taken up.

Try jacking the car up at the back and leaving the rear bleeders open over nite to let the air escape by its self, then bleed normally.

Good luck

[Peetee]

The fluid chamber in the master cylinder feeds the piston chamber via two small holes which can become blocked. When this happens it's possible for there to be no fluid in the piston chamber while the M/C appears to be full.