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750iL - 1991brake booster

Discussion in 'E32 (1988-1994)' started by dbogdan, Apr 7, 2010.

    dbogdan guest

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    Does anyone have instructions on how to remove and replace the brake booster? I'm leaking pentosin all over the place. Looks like a major pita.
    • Member

    bcweir

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    If you're leaking pentosin, it's not coming from the brake booster.

    That's coming from your power steering reservoir.

    Your brake booster should contain brake fluid, not pentosin.

    Brake fluid and Pentosin are not the same. The E32's equipped with LAD self-leveling suspensions (all iL cars) use this to maintain the rear suspension ride height and manage Servotronic speed sensitive steering pressure. The E32 steering pumps are prone to leaking around the low pressure and high pressure hoses, and through an internal seal that can also cause a slow pressure loss.

    dbogdan guest

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    Incorrect my friend. This is a hydrostatic brake booster. Anything pre 12/91 has this setup. The Power steering system self leveling shock system has a direct link (hose) right into the booster. I think the newer ones might be vacuum based, but I am not sure. I am aware that pentosin and brake fluid are not the same pentosin chf 7 is green. It is dripping out of booster. The brake fluid reservoir is full of brake fluid.

    Believe me I wish it was the PS reservoir, cause that would be an easier task. So like do you have instructions for removing this or are you just trying to bust my balls?
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    bcweir

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    Interesting. Thanks for the correction

    Learn something new every day

    Nope. I don't hit below the belt. Not very sporting.

    Actually, you double-posted this elsewhere, and that's where I posted my links. Certain members WILL try bust your balls over double posting the same issue in more than one section of the forum. Not me of course. cough, cough, Krieger might, cough cough, name dropping. Sorry.

    Here the links (again)

    http://bmwe32.masscom.net/maxf_website/h31_breakdown.htm

    http://www.bimmerboard.com/forums/posts/738610/

    dbogdan guest

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    Thanks for your help. Yes I did post this in two spots. In DIY and here. Wasn't sure where to post it. These 750s are very strange birds and not built for your average backyard mechanic. The sad part is I cannot afford to bring it to a dealership. I'm sure this will be a $2,000.00 investment if they get their hands on it. The car is only worth about $2500, so it's a stretch to dump cash into it. I replaced the exhaust system about a year ago and the guy at the parts store asked me why I wanted to invest that kind of money into it. We all know why we do that! It's a great car.

    I liked the article you sent about changing the plugs on that side. I spent at least a hour getting to plug 12. I removed the electrical stuff (I don't know the name for this piece) to get to it.

    I also found an article on rebuilding the unit without removing the housing. It appears that the issue is in the front of the unit where the master cylinder and the booster meet, so I'm going to attempt O ring replacement first. I see the spring is a major deal to put back in here.

    Thanks again.

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