ATF leak.

[Theantony]

I’ve just got an atf leak. There’s a puddle on the floor and after topping up the reservoir it’s lost about 1/4. The brakes go flat then hard then flat and I saw a load of atf fluid spewing out when the brakes are pressed engine on coming out from the bulkhead end. I’ve had the power steering pump changed about 4 months ago. Thanks Antony.

[Theantony]

Ok I found the problem seems to be a bad seal on this booster. What is this actually called and is there a seal kit.
Thanks

[Theantony]

I know it says power break booster but it’s got atf coming out of it and not break fluid.

[Theantony]

Here’s a pic

[RossDinan6]

The break booster uses ATF From the hydraulic pump that also powers the steering. There is not a kit that I am aware of. They use a one time shearing bolt on assembly.

When mine started leaking I took it apart using a pair of vise grips on the bolt head. Disassembled, cleaned and inspected the parts. Everything was in good shape so I identified the O-ring sizes and bought 10 packs of each locally for 5 or 10 bucks for the lot. It has been tight for years.

Not a tough job if you are competent with tools. Just pay attention to orientation of the parts, order of assembly, and be spotlessly clean working on it. Hydraulics are notoriously picky about contamination.

If you are in doubt at all, buy new.

[Sbeaud]

This diagram shows the brake boost system.

Scott

BMW Brake Boost and Power Steering System.jpg (138.11 KiB) Viewed 52 times