Well, i'm going utterly mental here, i've spent many, many hours bleeding these brakes

(all sierra hardware, MK hoses and copper lines)

every time i think each line is done (and am damn sure it is) it's not.

i can only assume air is getting in somewhere, does anyone have any suggestions?

Had exactly the same problem, if you haven't already then turn the rear calipers upide down and you will bleed the system fine!!

Rich.

unfortunately, it's not that, using drums on the back

Try wedging the pedal down overnight then bleeding them, having the master cylinder pressed down helps the air bleed back out of the system so Im told.
Also have you got any high spots or areas where air might accumulate (inline brake switch etc)? If so then you might need to reposition those to get it all out.

Have you tried a pressurised Easibleed type kit, screws onto the reservoir with the other end attached to an inflated tyre and forces the fluid through better.

I would check all the seals for leaks. Is the master cylinder new? Has it been apart and rebuilt incorrectly?

Are there any high spots in the pipework eg for the brake light switch or a balancing valve which could trap air?

Just a few thoughts

Cheers

mark

oops should type quicker

[Edited on 19/5/05 by mookaloid]

I've not rebuilt the master cylinder yet, that might be the next move.

There's no real high points.

I'll try jamming the pedal down tonight.

As yet, no luck using an ezi-bleed or normal methods.

If it is a Teves (ATE) mastercylinder it is highly likely it is drawing air in on the return stroke, trying bleeding again but using a very slow return stroke and making sure the nipple is properly open. Often with a used Teves cylinder sometimes pressure bleeding is all that will work because the posative presure in the resevoir keeps the seals expanded..

[Edited on 19/5/05 by britishtrident]

Go round all the cylinders and check the bleed nipple is at the top. Easy to fit the front calipers an the wrong sides leaving the nipples on the bottom.

quote:

---

Originally posted by Dusty
Go round all the cylinders and check the bleed nipple is at the top. Easy to fit the front calipers an the wrong sides leaving the nipples on the bottom.

---

haha.


that fixed it, they were on upside down, bled in about 5 minutes

I have had the same problem for months, and i was going insane!!!! even my wifes brother in law who is a mechanic for Ferrari never spotted that one!!!!!!

many thanks for saving my sanity.

I had exactly the same problem, really annoying but nice and easy to fix

I had a different problem - bought a pair of recon calipers and they were both left-handers! Took a while in my ignorance to work that one out...
... took one back and changed it.
David

[Edited on 20/5/05 by David Jenkins]

So the rule of thumb then is to make sure the bleed nipples are at the top???

Thanks for the tip guys. Ive just turned round the back cylinders so it looks like ive done the right thing.

yep. make sure that teh bleed nipples are at the top when bleeding calipers.

so in case of the rears ( thouse who are running rear discs with sierra calipers ) take the calipers off and blocking the pads with a block of wood, hold the caliper with the bleed nipple facing up to remove all the air.