WTS: Lycoming Vacuum Pump Drive

[Tom Thibault]

Working removed parts: Lycoming 61098, 72970, 71596, O6A19956, and STD-1774. See parts manual pages below.

ACS wants over $900.00 for these parts new. $150.00 takes all.

[Steve Alderman]

Hey Tom,

Curious if you removed the drive from your engine lately? Had a friend do this and he experience high blow by out the breather which took time to figure out. There is an pressure oil galley hole that lubricates the shaft of the pump that will spray a large amount of oil and exit out the crankcase vent. One needs to plug the hole or reinstall the shaft.

[Tom Thibault]

Steve,
Interesting. It was done very recently. Do you know the details of how to plug that hole?

[Steve Alderman]

Tom,

I don't remember exactly how my friend removed it. Looking at the drawings you posted, he must have just removed the gear/shaft from the housing and installed the cover plate on the end of the housing. It looks like one needs to remove the whole housing and then install the cover plate which is most likely what you did. The cover plate and gasket must seal the oil galley hole. Sorry for the scare.

[Danny Miller]

I installed the cover plate on the #2 adapter assembly for this reason when I removed my vacuum pump.

[Tom Thibault]

Danny,

So now I'm more confused than before about what is best. From the Lycoming drawings, it looks like "no vacuum pump", should have the gasket - then cover, directly on the accessory case. But I think you are saying you left all the vacuum drive parts in place and just put the gasket/cover directly where the pump was.

Anybody else know what is THE BEST WAY TO DO IT?

[Steve Alderman]

Tom,

Without having the accessory case in hand I'll try to explain why I chimed in. There is an oil galley hole on the vacuum pump pad. That hole sends pressure oil into the adapter assembly #2 in the drawing. It pressure feeds the shaft # 5. If I remember right my friend had removed the shaft and left the rest on and just put a cover plate on the Adapter. Without the shaft the oil galley hole sprayed oil inside the housing enough to also send it out the breather.

When I saw your post selling the whole assembly I remember my friend's problem and before I thought the whole thing out I warned you about a problem it does not sound you have. There shouldn't be any problem if you remove the whole assembly. Just remember there is a pressure hole on the accessory case vacuum pad that will have pressure oil. Make sure you have the correct cover and gasket that will seal that hole off.

[Danny Miller]

Danny,

So now I'm more confused than before about what is best. From the Lycoming drawings, it looks like "no vacuum pump", should have the gasket - then cover, directly on the accessory case. But I think you are saying you left all the vacuum drive parts in place and just put the gasket/cover directly where the pump was.

Anybody else know what is THE BEST WAY TO DO IT?

That's right.