Vacuum Pump Help

lmb118 · #1 09-05-2007, 08:45 PM

I lost my 200 hr vac pump today on my Lyc IO360 A1A. I can see the coupling has spun but I have not removed the pump yet. What are the chances that its just the coupler? It seems to have broke during a highspeed decent at 2900 rpm. Is it possible to overspeed a pump?
I would have thought it should have lasted longer ! What are my options? rebuild kit, overhauled unit, new?

I need opinions on how I should proceed.
How about the good the bad and the ugly on vac pumps brands ,design, overhaul etc.

Thanks
LMB

Ron Lee · #2 09-05-2007, 09:01 PM

But there are overhaul kits.

In my case the vanes broke which probably sheared the coupling.

frankh · #3 09-06-2007, 08:49 AM

1) Remove vacuum pump from engine
2) Open lid of trash can
3) Deposit old pump inside and replace lid
4) Buy a Dynon D100 and a Trutrack Pictorial pilot as backup
5) forget all about vacuum pumps...

Frank

Ironflight · #4 09-06-2007, 12:01 PM

I am afraid I agree with Ron - the coupler failure is the result of the pump locking up, not the other way around. I failed a number of vacuum pumps in the years I owned my Grumman, which is why I also agree with FrankH....if you can afford it, change over to all-electric. If you do stick with Vacuum, and you fly IFR, you probably want to establish a life-limit for your pump, and pro-actively change it out.

Paul

JHines · #5 09-06-2007, 12:35 PM

They make vaccum pumps now with inspection ports so you can check vane life.

If you stay with a vacuum pump, consider going to a wet model. The dry ones have good life. The trouble is their failure mode. They work perfectly until they're too far gone, and then they don't work at all. The wet pumps degrade in performance so you have some warning before they let go.

RV8N · #6 09-07-2007, 05:41 AM

My Rapco vacuum pump sheared the coupling at around 150 hours. I haven't disassembled the old pump but also was wondering about just changing the coupling. The coupling appears to be a polymer/plastic substance and looked like it might have overheated. Where broken, it had a crystallized appearance. I theorized that it might have become enbrittled due to the heat and that the pump might be ok. (there's the egghead engineer showing)

I finally decided to just replace it with a new Rapco pump with the inspection port. Don't know what difference the inspection port will make. If it wears out, it wears out.

Karl

cupaiole · #7 09-07-2007, 06:57 AM

If you want to keep the vacuum pump use a wet pump with a Airwolf oil/air seperator the wet pump will probable out last you engine. Who ever thought a dry vacuum pump was a good idea had his head up his ---. i think the FAA sould band dry pumps they are made to break!

AltonD · #8 09-07-2007, 07:02 AM

We had a wet pump on our old C172F. I think the pump was on its second engine.

gmcjetpilot · #9 09-07-2007, 07:56 AM

AltonD is right wet pumps are good, but than you need an air-oil separator. Also you will need more traps and filters to keep oil from migrating down the suction tube to instruments. It's heavier overall. Still if you want a reliable pump.....

There are some new design Vac pumps $688 with 5yr warranty.

http://aircraft-spruce.com/catalog/e...gmatekpump.php

Can't say of the new Vac pump design is better

200 hours is not uncommon for the typical Vac pump.