Hello, there's a cap in back of the brake fluid that's missing and releasing air. Every time i put my thumb with pressure the car idles perfectly. I tried looking for the missing at autozone but no luck and have no clue what it's called here's a picture. Any help would be much appreciated! Thanks

http://imageshack.us/f/580/engined.jpg/

 

according to my parts diagram, that fitting should have a nipple on the side, and there should be a hose that goes to a vacuum port on the intake manifold.... the vacuum that goes in there provides the power in your power brakes.

the cap thing and nipple are not called out as separate parts, they are all part of the brake booster as far as I can tell..


btw, big chain places like Autozone are near useless with european cars.

 

Thanks guys its called a Brake Booster Check Valve. I read if it leaks it could make the engine run rough. New cost $26 which is pretty damn expensive in my books for a little plastic part! Might just a good used one. Once again thanks

 

Assuming only the front piece of the check valve disappeared FWIF a US quarter fits perfectly to temporarily block the vacuum leak. It's not uncommon to blow that piece off in turbo cars running high positive pressures. In your 240, the vacuum pressure will actually hold the missing piece on. For you to lose it would indicate positive pressure which generally is not a good thing. Might need to check your flame trap.

 

weird that part isn't shown as a check valve on any of the parts diagrams (and doesn't even have a P/N).