In article ,
"Proctologically Violated©®" wrote:

How bad is that to do, momentarily? Can I get away with it, ie verify pump
direction w/ the pressure gauge?

Hydraulic pumps have a case drain that will dump leaked oil back to
the intake side. If you run the pump backwards and pressure up the side
connected to the case drain you can blow out seals or even hydraulically
push a shaft sideways in the housing, causing a lot of damage. While
you're trying to figure out which way to go, keep the flow unrestricted.

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B.B. --I am not a goat! thegoat4 at airmail dot net