Brake pad change - Richard Hall
Quick question for the mechanical experts. I'm about to change the brake pads on my Audi Coupe (1991, twin pot front calipers, ABS). I have read in a couple of places that with ABS systems you should not force the pistons back into the brake caliper unless the brake bleed nipple is open, otherwise you will trash the ABS pump. However, the Haynes manual does not mention this. Any ideas?
Re: Brake pad change - Andrew Bairsto
Do it anyway to be on the safe side its always the best way
Re: Brake pad change - Andy P
My Cavalier had ABS and I didn't do anything with the brake bleed. Have you checked with your local Audi dealer or one of the independant Audi specialists?


Andy
Re: Brake pad change - mike harvey
There is bound to be debris in the caliper behind the piston. It settles there as it's the lowest point. Do you really want to force this back into the ABS unit and risk a big bill? No. Undo the bleed nipple as Andrew suggests.
Mike
Re: Brake pad change - Guy Lacey
I know from previous threads that Volvo brakes are damaged irrevocably if u force the piston back.
Brake pad change - David Lacey
No need to worry about damaging the system retracting the pistons - just make sure the displaced fluid is vented off into a bleed jar or similar. Or even better still, change the brake fluid while you are there........

David
Re: Brake pad change - Richard Hall
Thanks for all the advice, which I have totally ignored. Of course, as soon as I tried to shift the first bleed nipple, it sheared off, leaving me with a choice:

1. Refit the old brake pads and discs, put everything back together and go and buy a new brake caliper (very expensive).

2. Take a chance on retracting the pistons (VERY slowly) into the caliper, and if the ABS pump dies, sue Haynes for not mentioning it in the workshop manual.

Being a gambling man, I went for option 2 and seem to have got away with it. The brake fluid was changed about 6 months ago, so I don't have to worry about the sheared bleed nipple for a while.

Changing the engine oil was even more fun - the sump plug nut was rounded off and I couldn't get anything to grip it (memo to Audi - 17mm is not an appropriate size for this component) so I ended up welding a large nut over the top of it (an old front hub nut from a Citroen AX - never throw anything away).
Re: Brake pad change - Martin
Good grief!

I thought I was unlucky....

If your coupe is like our 80 16V, the caliper pistons have a hex 'hole' in them so that you can use an allen key to 'rotate and push' the pistons back. Is yours like that?

Martin.
 

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