S3 spongy brakes
Discussion
jned2 said:
Changed front n/s calliper on the weekend, bled the brakes but can't get rid of a spongy feeling and the need to pump them before they firm up. Searched the forum and found something about bleeding the master cylinder and bias valve? Anyone had to do this this?
Depends how much air you let into the system while it was disconnected - if the main pipe run has got air in it that can be a job to bleed fully.It's also possible for a worn master cylinder to damage the seal during bleeding since it takes the pedal outside the normal range of travel, which could result in a soft/sinking pedal.
What method are you using to bleed the brakes? I have found that using a gunson Ezi-bled whilst also having an assistant depress the pedal was the most effective method.
I would also add to what has been said above....
when I changed my front callipers I could n't get rid of air in the system. It was then that I found the 5 year old rear wheel cylinders were weeping.
When I changed the wheel cylinders I could n't get rid of air in the system. It was then that I found that the master cylinder needed sleeving.
When I fitted the reconditioned master cylinder I could n't get rid of air in the system. I took the master cylinder off and sent it back to the reconditioner who tested it and found that it held pressure fine.
When I refitted the master cylinder I could n't get rid of air in the system. It was then I found that one of the ferrelly-things on one of the brake pipes at the rear had a hair line crack in it.
When I had made up a new brake pipe and fitted it I could n't get rid of air in the system. It was then I found that one of the rear wheel cylinders was leaking again.
When I had fitted a replacement cylinder I bled the system. AND THE BRAKES ARE AWESOME.
Keep the faith. It can be fixed - hopefully without replacing the entire braking system.
I would also add to what has been said above....
when I changed my front callipers I could n't get rid of air in the system. It was then that I found the 5 year old rear wheel cylinders were weeping.
When I changed the wheel cylinders I could n't get rid of air in the system. It was then that I found that the master cylinder needed sleeving.
When I fitted the reconditioned master cylinder I could n't get rid of air in the system. I took the master cylinder off and sent it back to the reconditioner who tested it and found that it held pressure fine.
When I refitted the master cylinder I could n't get rid of air in the system. It was then I found that one of the ferrelly-things on one of the brake pipes at the rear had a hair line crack in it.
When I had made up a new brake pipe and fitted it I could n't get rid of air in the system. It was then I found that one of the rear wheel cylinders was leaking again.
When I had fitted a replacement cylinder I bled the system. AND THE BRAKES ARE AWESOME.
Keep the faith. It can be fixed - hopefully without replacing the entire braking system.
If still spongy after trying the above I'd suggest flushing out the entire system with new fluid. Start at the cylinder furthest away from the master and pump until fresh fluid comes out then work through the others. I found the Ezi-bleed really to use and made this quite a quick job. This assumes of course that all you other cylinders and hoses aren't weeping. If all are OK and the pedal is still spongy then try replacing the old hoses with new rubber or better still, braided stainless lines.
Many thanks for all the helpful suggestions. Unfortunately I've not yet been able to have another look at the brakes as I've been side tracked looking after unwell elderly relatives. Had a little giggle at barkychocs comment though having asked Eurocarparts for a nearside caliper they then supplied an offside. I was about to fit it when my mate asked "how are you going to bleed it", good job he came round when he did.
Gassing Station | S Series | Top of Page | What's New | My Stuff