I attended an IA refresher seminar last week, and vacuum pumps was a whole course of instruction. Bottom line, don't waste your money or time with overhaul kits!!!! I know this first hand, and then had to buy a new/reconditioned one. The tolerances on the rotors are so tight that only a lab can get it right.
The FAA guy said there are flight schools that do get 2000 hours out of a dry vacuum pump. The secret was installing them correctly (how you hold a wrench while installing the pump effects how long it will last), really! This includes cleaning the lines and relief valves, changing filters, and if you are running de-ice boots with the pump then guess what--it fails sooner.
Last edited by Skymaster337B : 03-24-08 at 05:18 AM.
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