Bleeding back brakes on a sierra.

[luigi]

Hi Fellas.
I had to disconnect the back brake line on my sierra. I have been bleeding the line for an hour and still can't get any pedal height. Every time I change a wheel bearing I have the same problem. I put a tube on the nipple and into a container and pump till no bubbles come out. But still have a soft pedal.
Thought air might be getting past the threads on the nipple, so I put some Teflon on it. That didn't work either.
I was wondering , should there be an o/ring seal on the bleeder nipple?
I usually give up and drive it anyway. After a few weeks the pedal slowly comes back. I decided to give it a more determined effort to get it right this time, but I am now at a loss. I am probably just making some dumb mistake.
Any ideas?
Regards, Wayne.

[christover1]

I've found drip bleeding most effective, other than driving to brake shop for a good bleed.
Tried lots of other things, but nothing worked for me.
Brake pedal will improve as brake shoes bed in, too.

I just crack the nipple and let it drip slowly.
I found it hard to believe when a brake shop suggested it.

[christover1]

PS. Clamping off the soft lines is a good way to find out which end problem is at.
Ans bleed in correct order, not sure what that is for our cars,
but I start at longest, then work thru to shortest.
May not be right, but has worked for me.

[Richardnclark]

Hi Wayne, A couple of thoughts from me:
I clamp of the soft rear brake line and remove the nipple, clean the nipple thoroughly with a paper clip, then use a hands free bleed kit (cheap at autobarn or SCA). It has a magnet to hold the bottle above the highest brake cylinder point. The nipple locks of fluid via metal to metal at its point - not via Teflon tape. Works a treat!! I guess you have checked the brake cylinder for leaks and are using stock nipples in the rear.
I tried using speed nipples in the rear but found they leaked so back to the stock ones. Speed nipples work OK in the front. You can borrow my bleed kit - just call me. Cheers Richard

[luigi]

Hi Fellas.
Thanks for the advice. I have tried a bleeding tool. It has a one way valve on it and is supposed to let the air pass under pressure. The problem is, when I open the bleeder nipple the fluid leaks passed the threads on the nipple when under pressure. If I only open it about half a turn, it is loose. So no matter how well the tube seals on the nipple it leaks passed the threads. I tried to seal the threads with Teflon, it kind of worked. The wheel cylinder is a reco from ABS. I think maybe the bleeder nipple doesn't work the way it should.
I reckon the only way to do it is with 2 people.
But I eventually got it nearly right with a heck of a lot of mucking around.
I will be seeing my brother/inlaw tomorrow. He is an experienced 4 wheeldriver and pretty cluey.
Thanks , Chris and Richard.
Regards, Wayne.

[Richardnclark]

It sounds like the nipple is not seating properly in the brake cylinder to lock off the fluid. You should not need Teflon!!!! Try changing the nipple first then the cylinder if the first action fails! Richard

[luigi]

Hi Fellas.
Hi Richard. Its difficult to explain in words. The bleeder seals off fine when it is tight. The Teflon was only to try and stop air getting passed the threads when the nipple was loosened. I saw a bloke on youtube put grease on the threads for the same reason.
I have got it good enough to drive. Thanks for your advice.
Regards. Wayne.

[jonfromhamilton]

i had a problem like this
it was the brand of brakes
bendix fixed it

[pezz]

i use a reverse bleeder similar to this one.....
http://www.youtube.com/watch?v=L0oUejw5Edc
just mine is cheaper version

cheers
madmax..... err pezz!