Vacuum solenoid valve

[earendil]

Hello,

Due to vacuum leaks I have pulled out the plenum and traced the leaks to the T-connectors at the vacuum check valves (will resolve one way or another).

However when checking the vacuum solenoid valve I observe the following behaveour which I am not sure is abequate:

At the side towards the vacuum reservoir it holds vacuum perfectly (as expected.. it is closed afterall).
At the other side it breathes freely from the filter end (sponge), but then I remove the filter and block the opening it sill slowly looses the vacuum.

1. Should it hold no vacuum at the driver's side connector (as mounted) and take air freely from the filter??
2. Is it a problem that it looses vacuum albeit slow when I block the filter end?
3. If it requires replacement - is there a substitute part from another (EU) brand car as I am in Bulgaria and would not want to wait a long time for the part, as the car is disasembled at an open parking and it will soon become too cold to work on it.. Would prefer to assemble it in the next few days.

Thanks

[earendil]

OK , scratch that.

I have reassembled everything.. but sadly after I completely understood everything..

Now it seems my vacuum ckeck valve needs replacing.. but instead of that, can't I simply put a simple one way valve at the plenum connector? It should do the same job?

[oldpro]

I think so I did that once on my 90 before I got rid of the secondaries and all the problems that go with it

[Ccmano]

Originally Posted by earendil

OK , scratch that.

I have reassembled everything.. but sadly after I completely understood everything..

Now it seems my vacuum ckeck valve needs replacing.. but instead of that, can't I simply put a simple one way valve at the plenum connector? It should do the same job?

That’s all the check valve is anyway, a one way valve. I’m sure you can source one locally. Some people move the check valve to just outboard of where the vacuum line plugs into the plenum on the driver side. That way the valve can be serviced (replaced) in the future without removing the plenum.
H

[Young1]

http://www.zr1.net/forum/images/icons/icon1.gif

This thread titled secondaries not working contains Info on locating a vacuum solenoid.

[earendil]

Originally Posted by Ccmano

That’s all the check valve is anyway, a one way valve. I’m sure you can source one locally. Some people move the check valve to just outboard of where the vacuum line plugs into the plenum on the driver side. That way the valve can be serviced (replaced) in the future without removing the plenum.
H

Thanks,

that's exactly what I did. The vlave is now outside.. would have put it under if I understood earlier what's what and how it works.. It was my first plenum pull but now I can boldly say I am intimately familiar with all of it it.

The car is now purring like a kitten.. at 675 rmp Used to hold 2000 rmp idle..

Plenum gaskets were almost non-existent and the T connectors at both check valves were loose...

Really glad I did this myself.. Big thanks to all the technical posts in this forum!

[Young1]

I am glad you had a success. Zip ties and clamps are you friends to solve vacuum leaks too on old systems. Enjoy!

[Paul Workman]

And, for future reference, Jerry's Gaskets.com has all of the parts needed to rebuild the entire vacuum circuit (and much more) - FYI