John Deere 2720 Hydraulic Pump Seal Issues

[smashedtoe]

Good Day all.

I have a John Deere 2720 compact tractor which I just repaired by installing a new hydraulic pump.

Everything seemed fine, but for some reason the shaft seal keeps blowing and leaking hydraulic oil into the engine.

Any suggestions or recommendations as to what would cause this?

Hydraulic pump is the proper one (PW1-D-8A) which was brand new via Yanmar. Zero modifications to the tractor or hydraulic system.

Only other additional comment is the original pump blew the internal seal at the back of the pump.

Appreciate all the help.

 

[oldnslo]

On most gear pumps there is a connection between the pump inlet and shaft seal cavity which keeps the shaft seal close to pump inlet conditions. If this connection is not drilled properly or you have to much internal leakage in the pump you can create high pressure in shaft seal cavity since the flow path is restricted

does the seal fail soon after start up or does it work for a few hours or days?

 

[smashedtoe]

Hi.

It’s a brand new pump and lasts for a few hours.