Vacuum hose mystery [Archive] - Bimmerfest - BMW Forums

Vacuum hose mystery

11-11-2009, 09:14 AM
My son just got his fist car and we are working on it together. It is a 1994 525it. We have fixed the power seats, glove box. power window. brakes etc and all is going well. There are two hoses which we are having trouble with. There is a hose which comes off the servo unit and is next to the brake master cylinder. It goes to a "non return Valve" Part no. 34331158106 on There is a very small nipple which comes off the valve and it has vacuum. Does anyone know the purpose of the vacuum and where a hose if any is suppose to go. The check engine light is not on and it does not seem to effect the rpm when I cover the hole with my finger. The other mystery hose is near the front of the head and is for pressure relief. It is a "T" with a large strong hose and a much smaller and weaker (spongy) hose just hanging down. Does anyone know where this is suppose to attach? Thanks for any help you can give. Michael:dunno:

11-13-2009, 03:48 PM
Can you post pictures?

11-13-2009, 06:55 PM
Yes, I will try tomarrow, thanks