I am curious if anyone here has a car that uses a standard vacuum brake booster. If so, did you find that you needed to update the check valve in order to accomodate the boost pressure? I'm guessing that if the OEM brake booster check valve fails, it will be short life for the booster itself.
I know the e28's all (or a majority at least) run the hydraulic brake assist systems, so this is a bit off topic, but any help would be appreciated.
I'm also curious where else check valves are commonly used in the l-jet and/or motronic systems where they may not have existed prior to turbocharging.
Thanks again,
Jason
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Brake Booster Woes? Sortof OT...
All M20 e28's use the vacuum booster. There are probably more 528e's out there than 53x cars. So really the majority probably uses vacuum boosters.
Anyway, I'm using the stock check valve system in mine, and I have no problems. The check valve normally does not allow boost into the booster itself. The booster holds a vacuum, so wether its boost pressure or just atmospheric pressure trying to get in, the check valve should prevent boosting the booster. I guess if it failed it could damage the booster. I'm sure it wasnt designed to hold positive pressure.
Anyway, I'm using the stock check valve system in mine, and I have no problems. The check valve normally does not allow boost into the booster itself. The booster holds a vacuum, so wether its boost pressure or just atmospheric pressure trying to get in, the check valve should prevent boosting the booster. I guess if it failed it could damage the booster. I'm sure it wasnt designed to hold positive pressure.
Ahh, interesting. I'm really just curious what the breaking point on the check valve is in terms of boost. Mine appears to have broken and it took the booster out with it. I'd prefer to fix it right rather than to use a stock check valve if there is a necessity for that. For all I know the stock check valve may have failed for another reason though.
Jason
Jason