StratfordShark

I'm researching brake master replacement procedure for my 91 S4 auto. First place I looked was WSM (47-13).

The photos are for earlier MYs, and I understand that for my ABS car the 2 lines at MC are routed to the ABS hydraulic unit in rear left wheel well, and regulator valve is located there.

So not actually relevant to my car, but I'm puzzled by the photo in the manual which I think relates to an 1984- car without ABS. What is the cross-shaped part shown in upper left of the photo? The 2 arrows indicate brake lines should be undone at these points, but why do that if brake lines are detached at the master?

Nothing to do with my MY really but it's really bugging me!

Thanks

Adrian

fraggle

First step shoud be "REMOVE ENGINE".

I would not break any hydraulic lines until you get the 4 bolts loose that hold it to the firewall. I hope you have long skinny arms!

Mrmerlin

thats cross part is a splitter ,
the rear brake bias line comes from the valve,
then it splits to the rear brakes.

ammonman

The lines from your MC are routed to the ABS unit located in the left front near the PS reservoir, not left rear. The unit in the left rear wheel arch is for the PSD electronic limited slip differential system.

The brake bias valve will be screwed in to the ABS unit on the outlet to the rear brake circuit.

Mike

StratfordShark

Thanks all for enlightenment!

I don't know how I confused PSD with ABS units.

Mine is RHD so may be easier to get to the bolts holding MC to firewall. I've got good selection of swivel-head ratchet wrenches and 1/4" ratchet and UJ so should be able to reach somehow.

I had incident last week where pedal sank to floor when I started engine, but behaved ok after that. Flushed brakes yesterday and old fluid was clean (and level at Max) so beginning to look like MC seal is failing. The brakes feel good after flush but I don't want to risk complete failure of MC