Board logo

Trying to understand vacuum hoses
craigdiver - 16/3/18 at 10:44 PM

Trying to get my head round the vacuum hoses on my BMW M52TU25 engine, one in particular (which can be seen in photo below) was feeding the brake master cylinder, it appears from under the intake manifold then tees onto a pipe that goes to the intake a few inches after the MAF, the branch of the tee goes through what looks like a one way valve then went to feed the brake master cylinder. Can I remove these pipes and cap off the pipe from under the intake manifold and air intake?

rodgling - 16/3/18 at 11:25 PM

Presumably if it was supplying vacuum to the brake booster you don't need it - so block it off. The RealOEM diagrams are helpful for this sort of thing:

http://www.realoem.com/bmw/enUS/showparts?id=CD11-EUR-01-1998-E36-BMW-328i&diagId=34_0534

craigdiver - 17/3/18 at 07:00 AM

quote:
Originally posted by rodgling
Presumably if it was supplying vacuum to the brake booster you don't need it - so block it off. The RealOEM diagrams are helpful for this sort of thing:

http://www.realoem.com/bmw/enUS/showparts?id=CD11-EUR-01-1998-E36-BMW-328i&diagId=34_0534


That was very useful - thanks. Looks like the pipework that I described is part of the main vacuum generator and the pipe to the air inlet is for vacuum control - so will leave as is. I will remove the pipe that went to the brake servo and blank it off.

rodgling - 17/3/18 at 03:43 PM

By the way, do you have the ASC traction control system there? If I were you I'd remove it and replace with the standard throttle body, by all accounts it's not worth having. Might as well simplify, save a bit of weight and remove an airflow restriction? I probably have a spare standard 328 throttle body lying around if you want one?

craigdiver - 17/3/18 at 03:49 PM

quote:
Originally posted by rodgling
By the way, do you have the ASC traction control system there? If I were you I'd remove it and replace with the standard throttle body, by all accounts it's not worth having. Might as well simplify, save a bit of weight and remove an airflow restriction? I probably have a spare standard 328 throttle body lying around if you want one?


I don’t think the donor 2000 523i had traction control (M52TU25 engine)? how can I tell?

rodgling - 17/3/18 at 04:33 PM

Judging by this diagram it did, or at least it might have been an option:

http://www.realoem.com/bmw/enUS/showparts?id=DM31-EUR-01-2000-E39-BMW-523i&diagId=13_0409

Just see if it has two throttle bodies (ASC) or just one (no ASC). ASC TB is part 4 in that diagram, main TB is next to part 6.

[Edited on 17/3/18 by rodgling]

craigdiver - 17/3/18 at 05:26 PM

does this help.....