Vacuum servo question

[AndyP]

I'm trying to test my vacuum servo for leaks and I've connected a Mityvac to the vacuum inlet of the servo but can't get it to pull a vacuum at all. Do you think a Mityvac is man enough for this or do I need a bigger pump?

I'm thinking that I should be able to pull and hold a vacuum on the servo, right?

[Pirvu Eugen]

Do you have an master cylinder with gasket installed Andy?
Iff not... You loose all vacuum trough master cylinder opening.
Goodlyck!

[AndyP]

The servo is still on the car, so yes it has the master cylinder attached.

[quattro-nick]

you can check the one way valve in the vacuum hose to see if it's work properly.
if this is okay you can let the engine running on idle for 5 min. and then turn it off
wait for a few minutes and pump on the brake pedal
normaly you feel a light brake pedal until the vacuum is gone,i think about 3 or 4 strokes
if you immediately have a hard pedal you have a leak on the vacuum booster or the one way valve is leaking

[diesel des]

I'm trying to test my vacuum servo for leaks and I've connected a Mityvac to the vacuum inlet of the servo but can't get it to pull a vacuum at all. Do you think a Mityvac is man enough for this or do I need a bigger pump?

I'm thinking that I should be able to pull and hold a vacuum on the servo, right?

Yes you should. It seems there are many leaking servos around even some new ones. On a good servo you should be able to suck with your mouth and feel the vacume hold.

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[RichLV]

Just changed mine recently. Was an easy diagnosis. Removed it from the vacuum system completely and the RPM dropped to the levels they should be in. When it was connected I had +100-150 more.

[AndyP]

Yes you should. It seems there are many leaking servos around even some new ones. On a good servo you should be able to suck with your mouth and feel the vacume hold.

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Just been re-reading this thread where you detailed your woes with leaking servos, did you find out where they were all leaking from?

http://www.s2forum.com/forum/showthread.php?p=860729&highlight=servo#post860729

[diesel des]

Seemed to be leaking at the rod that goes to the pedal from memory. It was aligned ok so I don't know why. You could hear them squealing in the car.

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[AndyP]

Well I can't hear a leak and the idle seems OK, but I can only get one press of the pedal after the engine is off before it goes hard, even if I don't press the pedal it goes hard after a couple of seconds. I've ordered a new one, but I'll investigate further this weekend to see if I can find where it's leaking.