1982 320i manual - Brake booster o ring inside?

For all your questions, problems and DIY stories
Post Reply
Posts: 2
Joined: Thu Feb 02, 2023 12:49 am
My E21(s): 1982 E21 320i Manual

1982 320i manual - Brake booster o ring inside?

Post by e21-V3 »

Hi! Apologies if this is covered somewhere. I did my best to search the site but could no come up with anything.

1982 usa 320i manual

I just removed the brake master cylinder to replace it as I have no braking power and bleeding the brakes yields endless air bubbles. I discovered when I depress the brake pedal I can feel air seeping out the break line ports on the master cylinder.

So i removed it to check it out/ replace it. Now when I look inside the brake booster to make sure it is all dry inside, I see a large rubber o ring hanging inside on the push rod. This is not the seal that goes between the master cylinder and the booster as that is still on the master cylinder and in decent shape. I can't seem to find any diagrams on the internals of the booster so I am wondering where this o ring needs to go. I have supplied an image looking inside my booster and a link to the image if that doesn't work. Thanks for any help!



User avatar
Site Admin
Posts: 28925
Joined: Tue Sep 14, 2004 12:23 pm
My E21(s): '81 323i Baur
Location: The Netherlands

Re: 1982 320i manual - Brake booster o ring inside?

Post by Jeroen »

Welcome here! If you have some time to spare, please post a little presentation of yourself and your E21 in the owners gallery!

I took a look at the parts catalog for the Euro 318i, should be the same as 1982 US 320i, found O-ring P/N 34 31 4 650 345

Nr 6 on this diagram


http://nl.bmwfans.info/parts-catalog/E2 ... ylinder_2/
Regards/groeten, Jeroen
Post Reply