H31 leak from two plugs, what are these?

[youngbimmer]

I’ve owned 4 e32s now, but this is the first with the hydraulic brake booster, I thought it is interesting to find in the 735, as both my 89s and my 90 had vacuum boosters. Anyway, I noticed ATF leaking all over my brake bomb and power steering lines, it appears to be from the two sensors/plugs? That hook in above the brake bomb? Both of the plug boots are wet with ATF, reservoir was low, so I added more ATF. Is it just the seals around the sensor/plug leaking? What is the part to replace? Pictures attached!

[youngbimmer]

Update: appears to be leaking fluid level and pressure switches, which according to my research from shogun's old posts, can be prone to leaking over time. Both have copper crush washers. Parts:

https://www.fcpeuro.com/products/bmw...or-34331150922

https://www.fcpeuro.com/products/aud...ro-61311362977

Seems I will be replacing both, maybe a good time to replace brake bomb as well? Is it as involved on the 735 as it is on the 750? Looks like everything on this car is original....I'm not comfortable driving it with 30 year old parts. Parts list so far:

BMW Brake Pressure Switch - ATE 34351182270

BMW Brake Fluid Pressure Sensor - ATE 34331150922

BMW Brake Pressure Accumulator - ATE 34331162054

Anything else to add while I'm in the brake system?

[CroughtonE32]

I thought you had a 1990 now. What year is your 735I? My boost comes from the intake manifold. I replaced that leaking hose a couple years ago with new connectors at each end. Made quite a difference in pedal feel.

[youngbimmer]

I thought you had a 1990 now. What year is your 735I? My boost comes from the intake manifold. I replaced that leaking hose a couple years ago with new connectors at each end. Made quite a difference in pedal feel.

My replacement is a 1988, build date 12/14/87, so it is quite old
It has some oddities that are not common with later 735i: H31 brake booster being one of them, real wood trim that was not laminated like in the later models, speaker fader switch, etc

[CroughtonE32]

Interesting. I had a brake bomb on my 1983 733I E23 back in the day. It used to fail all the time. Looked like a mini bowling ball. Nitrogen filled if I remember, but I could very well be wrong.

[shogun]

The problem with the switches on the pressure regulator is the plastic around the connector pins, that get's brittle and then the oil comes out thru the plastic, just replace them, not too expensive, also available from ATE
https://www.autohausaz.com/catalog/c...tch?s=d&page=1
61311362977 ATE Brake Pressure Warning Switch; Fine Thread; 20 Bar Mounts horizontally on side of DS regulator. 1 per car. For models with production date through 2/1988.
34331150922 ATE Brake Pressure Warning Switch; DS Regulator Sensor; Coarse Thread 1.5 Bar Vertical mount at top of regulator. 1 per car. For models with production date through 2/1988.