Leaky booster

[canucke30]

Hey guys,

I have discovered a bit of a problem with my booster. If i hit the pedal after I turn off the car (building up pressure in the booster), it leaks brake fluid everywhere! Obviously, I have a leaky booster. Is there anyway to fix it without replacing the whole thing (JB weld, etc.) or should I just bite the bullet and get a new booster. If I do that, are all e30 booster's interchangeable? In case it matters, I have an '84 318i.

The only reason I ask about fixing it rather than replacing it is that I blew my diff the other night and need to fix that ($$$).

[zxert]

Does the booster hold fluid?

I assumed that the booster simply acts hydraulically to move the master cylinder. Most leaks of that variety come from bad seals in the MC.

I may be wrong.

[canucke30]

I am not sure. I can see exactly where it is leaking from, but i suppose it could be leaking at the seal and dripping down the booster.

[zxert]

Yes, thats more than likely the problem. You want to replace the master cylinder. I don't know which brake boosters are compatible with our cars(84 318). But I'll do some research.

[zxert]

http://www.e30tech.com/forum/showpost.php?p=1073848&postcount=11

That about sums it up.

[zxert]

http://www.e30tech.com/forum/showpos...8&postcount=11

That about sums it up.

I'm a little late diving in here but here's whats up. You need a MC with 3 ports. Some ABS cars have 3 some have 2. The 3 port MC will have a plug on the bottom port. I just replaced my MC with one out of a 325e thinking the larger piston will give me more braking power. I should note I did a rear disc swap a while back. Anyway, I got no improvement with the larger MC.

[jlevie]

The booster itself has no fluid in it. If you see brake fluid leaking the source will be the master cylinder. And if brake fluid has leaked into the booster both it and the master cylinder will have to be replaced. If you don't replace the booster the brak fluid will destroy the booster pretty quickly.

[DREWHALL]

Beat me to it. Just had to replace a booster and mc in a E65 745 under warranty. I was suprised how easy it was.

[canucke30]

Beat me to it. Just had to replace a booster and mc in a E65 745 under warranty. I was suprised how easy it was.

That's good to hear!