cessna gearpump

tony2 · Sep 20, 2010

I own a Wain Roy tractor /backhoe loader it has a cessna gear pump and a cessna 2 spool control valve i would like any sugestions or ideas as to why i keep blowing out the input shaft seal i have changed this seal a few times now have loc tited it in put a washer in frnt of it now the seal stays put and the rubber part blows out around the shaft if anybody knows anything about the pressure release valve and how to adjust it or any other ideas i would be happy to lisen

mite-help · Sep 20, 2010

sounds like you may not be replacing the high-pressure seal-some pumps have an outer seal for dirt,etc & another seal deeper into the pump to handle the pressure.

Janicholson · Sep 20, 2010

Another possible issue is that all gear and bearing leakage must be directed back to the suction side of the pump. (usually a thin metal plate that is sandwiched into the pumkp at both ends) if this is in backwards, or wrong end, it will pressurize the seal. It cannot ever stand real hydraulic pressure at all. Jim

CAROGATOR · Sep 20, 2010

Definitely an internal leakage. The outer seal is only a 20# seal. you probably have worn shaft bearings or gears cauing a leak bypass. The pumps are cheap and better than rebuilding.

greygoat · Sep 21, 2010

The Cessna is a "throw away" pump, meaning it"s
cheaper to replace it than to try to rebuild it !
It"s an aluninum pump with brass bushings- no
bearings. When the bushings get enough wear they
allow some slop in the gears, which undercut the
pump case, allowing high pressure oil to get
around the pump shaft and force out through the
oil seal. It"s time to replace the pump !

cessna gearpump

tony2

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mite-help

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Janicholson

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CAROGATOR

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greygoat

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