My master cylinder has been leaking for a good bit and I finally got around to replacing it. Along with the MC I decided to replace the booster since fluid got into it.

I get everything out and put everything back in and all the measurements and adjustments are perfect. With the car off the brakes aren't engaged and you can roll the car around. Once you start the car and pump the brakes and build pressure they slowly close and don't release and the longer you drive the worse the brakes clamp down.

The check valve is fine and in the right direction and I'm using a stock 89 non abs MC and 89 non abs booster so everything matches up and what not.

I talked to a lot of people and they said that any advance auto parts or auto zone booster usually do that and wont release vacuum. I guess it makes total sense since the booster I bought from advance auto parts is ALOT lighter, not the same shape, and is just cheap looking, but everything matches up and I'm 100% sure its the right part.

Has anyone else had problems with non oem boosters?

I went ahead and bought an OEM booster and it was a good bit of money compared to the rebuilt one I bought. It will be here tomorrow and just checking if that's the problem.

 

Bump.

 

Bump, put my old leaky OEM one in today so I could drive the car while I wait for the other booster.

Thumbs down for Advance and Autozone. Ill prolly never go there again even if I have to. I bought a set of their flare nut wrenches and the 10mm wasnt even metric it was more like standard so I didnt even attempt to take off my lines with that and just bought some from Sears.