since 1940

Aircraft Maintenance TroubleShoot

Rapco dry vacuums pumps

 Garwin vacuum pumps Troubleshooting

Deice boot malfunction. Boots don't inflate Early pump failure. Short pump life Excessive oil in discharge Frequent regulator adjustments High vacuum pressure. Low vacuum pressure Oil discharge on Garwin vacuum pumps  Suction gauge fluctuates Vacuum gauge follows engine rpm Where to get additional information

When replacing a failed pump what should I inspect for

1) A proper functioning pump creates a vacuum in the system lines. When the pump fails internally, the carbon rotor and vanes break into several pieces creating very fine particles of carbon and carbon dust. The vacuum that is present will suck carbon debris back up into the inlet hose possibly contaminating the regulator. In some cases instrument contamination can occur. It is very important to remove the hoses from the aircraft and clean them out thoroughly, making sure to remove all loose debris. It is imperative to clean the entire system after a pump failure. This preventive maintenance procedure will eliminate carbon F.O.D. from entering your new pump.

(2) After you have installed the new replacement pump, We recommend using a commercially available test kit to make sure the aircraft vacuum system is working properly. A faulty regulator , dirty filter(s), or a crimped or partially collapsed hose can cause excessive system vacuum. This increases the load factor on pump and shortens pumps life.

(3) If you have a mid time engine, replace the oil seal in the engine AND 20000 pump mounting pad. This area could be dry now, but, due to age the seal could start leaking in just a few hours allowing oil contamination in your vacuum pump, causing premature failure. Less than $5.00 dollars spent here could save you hundreds of dollars later

I'm frequently replacing pumps - what could be causing this

1. Make sure that you have the correct pump installed on your aircraft.

2. Check your hoses to make certain that they are not collapsed or kinked.

3. Faulty or improperly set regulator.

4. Replace the system filter(s). A dirty or clogged filter will reduce vacuum at gyro gage and increase load factor on pump causing premature failure.

5. Make sure that no oil contamination is entering the pump

Inside a Rapco vacuum pump showing carbon rotor and carbon blades.

Does a new pump include the coupling

Yes, sometimes when you remove the pump the coupling pulls out of the pump and remains
in the adapter drive on the engine. Reach in and pull the coupling out.

Copyright 2003 by Sacramento Sky Ranch Inc. All rights reserved.  Prices subject to change without notice. Not responsible for typographical or misprint.
Disclaimer: sacskyranch.com contains abundant information relating to aircraft maintenance. The information provided  is not intended to supercede or supplement the F.A.A. approved  maintenance and/or operator’s manuals. Those F.A.A. approved manuals must be utilized when performing maintenance and/or operating aircraft.