Mitsubishi d1850FD hydraulic pump seal failure

[daddio1000]

The seal on the hydraulic oil pump of my Mitsubishi d1850FD tractor keeps failing. It moves forward out of the housing seat and allows hydraulic oil to fill the engine crankcase. There is no retaining clip for the seal and the housing is in decent shape. Does anyone know what is causing this to happen or have any ideas for troubleshooting the issue?

 

[Kernopelli]

It has been some time since I've had one apart so I don't remember how the shaft seal is retained but it is hard t imagine there isn't something there designed to keep it from doing what you describe. I suspect the seal itself is damaged or worn. I assume it is a Kayaba pump, I'd check for a new seal from one of the parts distributors online and see if a new one is available.