vacuum gauge Vibrating Vacuum gauge

[Jake35]

For the last month or so on start the vacuum gauge vibrates extremely rapidly. It smooths out above 1500rpm. It does the same when I engage the back-up system. The pump has about 170 hours since new. Any ideas?

Jake35 

[Marauder]

1 hour ago, Jake35 said:

For the last month or so on start the vacuum gauge vibrates extremely rapidly. It smooths out above 1500rpm. It does the same when I engage the back-up system. The pump has about 170 hours since new. Any ideas?

Jake35 

How does the vacuum read through this process and when it does stabilize? It could be a number of things. A small leak, a failing gauge or something going on with the pump.

[N201MKTurbo]

How does it do with the engine off and the standby running?

I have always found this was the precursor of the pump failing.

Have you inspected the pump to see if it has oil on it from somewhere like a failed oil seal in the drive gear?

[Jake35]

• Thanks for the reply. The backup is engine vacuum powered not electric so that doesn't apply but I need  to take a close look at the pump - which I have not done yet.
• Jake35

[Jake35]

1. Thanks for the reply Marauder. The gauge indications (range) are normal.
2. Jake35

[carusoam]

Quick question...

Is the gauge vibrating or the needle vibrating?

If the gauge is vibrating... other things like the compass is shaking as well...

Hints of vibrations shaking the plane...

Best regards,

-a-

[ragedracer1977]

I’m probably going to need to replace my pump sooner rather than later.  My needle is doing the same.  Is there a particular pump that is better for an O360-A1D than any other?

[Andy95W]

I strongly recommend the Tempest vacuum pump.

I just installed one 2 years ago.  Very well engineered and a very well-thought out oil diverter piece that should help keep oil off the drive gear (one of many things that cause them to shear).

When you get your new one put on, make sure your mechanic replaces the seal that goes in the drive shaft assembly.

https://www.aircraftspruce.com/catalog/eppages/lycomingorings_08-19956.php

 

[Jake35]

Carusoam - It's just the needle vibrating not the gauge.

Jake35

[Rotorhead]

@Jake35 ever come up with a solution to your problem?

[A64Pilot]

Not sure if they are still available, but I had a wet vacuum pump on my Maule made by Airwolf, they are essentially the same as a Pesco pump.

But they will last the life of an engine, but ain’t cheap. They also emit a fine mist of oil being a wet pump, so it’s best to have an air / oil separator.

Any dry pump is a consumable and ought to be replaced every 200 hours or so if you fly IFR and depend on the vacuum source, although I’ve seen them go over 500 hours