e34 520i 1988 brake servo/check valve...

[nsbone_1988_520i]

Hi,

Can i convert stock check valve (with multiple vacuum hoses) to simple 2-port check valve- one to servo and another to manifold? of course, i'll seal the rests.

Or there are reasons why it's being designed like that?

My check valve leaks at # 17 inlet, which i am interested to know where it goes to. If i cover it with my finger, the engine idling goes up and down... I thought, i could make it simpler with 2-port check valve...



Appreciate for any help.

thanks in advance,
rahman

[joshua43214]

Part 17 is a vacuum cap. Just put new cap on, you can get them from any autoparts store, or find something rubber to stick over it. The check valve is technicaly a metered vacuum leak to the servo, if you use something in its place that meteres a different amount of air, you can have idle diving or idle quality issues especialy after hard braking. Picture coming to a hard stop behind someone who suddenly decided they just now needed McDonalds and your car stalls on brakeing, or the engine surges(very bad on auto cars).

A piece of vacuum hose with a BB in it works even if its not elegant.

[nsbone_1988_520i]

Part 17 is a vacuum cap. Just put new cap on, you can get them from any autoparts store, or find something rubber to stick over it. The check valve is technicaly a metered vacuum leak to the servo, if you use something in its place that meteres a different amount of air, you can have idle diving or idle quality issues especialy after hard braking. Picture coming to a hard stop behind someone who suddenly decided they just now needed McDonalds and your car stalls on brakeing, or the engine surges(very bad on auto cars).

A piece of vacuum hose with a BB in it works even if its not elegant.

Josh,
Thanks for the advise.

I just use a one-way valve found from my e21 as replacement to the check valve assembly, and it works so far. BTW what is a "BB"?

thanks...

[joshua43214]

Josh,
Thanks for the advise.

I just use a one-way valve found from my e21 as replacement to the check valve assembly, and it works so far. BTW what is a "BB"?

thanks...

A BB is a .17(?) caliber pellet used in childrens pellet guns

[nsbone_1988_520i]

A BB is a .17(?) caliber pellet used in childrens pellet guns

Oooo... ok... thanks, i used something similar (spark plug/large nut)...