Brake booster replacement problem! RHD 528i

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ausjet
Posts: 26
Joined: Tue Dec 14, 2010 6:04 am

Brake booster replacement problem! RHD 528i

Post by ausjet »

Hi everyone from Australia!
I have a very strange problem that I’m hoping someone may be able to help me solve. I recently replaced both vacuum brake boosters on my RHD 528i with reconditioned ones and now I have a very strange problem.
After bleeding the system, now it appears as though the engine vacuum is holding the brakes fully on! With the engine running, the car is unable to move as the brakes are on, when you switch off the engine, you can hear the brakes releasing!
The check valve on the vacuum line to the brake boosters from the top of the engine has been checked and is working fine and in the correct orientation.
Has anyone ever experienced this problem? It’s very strange indeed as all that was done was the direct replacement of both brake boosters.
Any help or suggestions are appreciated as the brakes are locked on with the engine running and the car cannot be moved unless you really press the accelerator!
Thanks Scott.
1979 E12 528i Topasbraun Metallic
1986 E30 318i Platenen Green Metallic
2010 Ford Falcon FG XR6 Ute
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Mike W.
Posts: 2798
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Re: Brake booster replacement problem! RHD 528i

Post by Mike W. »

You of course have that bizarre system over there that BMW put on RHD cars, but I'll take a stab. I bet it's being preloaded. That you need to adjust the link between the master cylinder linkage and the servo, that it thinks the brakes are being applied. Then again, looking at the Realoem pic with the little vacuum pods off the main servo, I'm not sure about anything. That's a really complicated system. :shock:
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
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