It's not too complicated to flush a rotary pump. Here's my method. I flush with either clean pump oil or if very dirty, Automatic Trans. Fluid (ATF) which works quite well, and has better lube qualities than Kerosene.
It's not necessary to fill the pump to capacity when flushing. Use about one third fill, run for a couple minutes and discard it. If the pump is really dirty, then it may take a half dozen flushes. Just check the drained oil for sediment and general debris. Once the flushing oil is clean.. Use some new, regular pump oil.. and run the pump for about 5 mins. and drain it.. In each case... let the pump run open to the air.. to get maximum agitation in the oil.. This will clean most rapidly. Then use a full charge of oil.. and run it blanked off, with a gage, till the pressure stabilizes.
For a pump with a fair amount of hours on it, pumping much below 20 microns even on a small volume, may not happen. Rotor, vanes or reed valve or the shaft seal are all likely places for leakage. Other than the reed valve and shaft seal.. the remainder are rather more involved to improve, without some careful lapping.
Dave Cooper
Created on Saturday, April 07, 2001 2:05 AM EDT by David Cooper