I have a 92 648d Skidder that has been leaking hydraulic oil from the shaft seal for about 12 years. It finally broke yesterday so I broke down and pulled the pump and put a new seal in, it lasted about 30 seconds before it started leaking again. The hydraulics are strong and the leaking slows when the machine warms up. I don’t think the pump is gone but something is causing it to pressure up. Thoughts as to where to start or ideas on how to fix. Thanks in advance.
Welcome to HEF Phillip ! Let's start with the complete machine serial number. Somewhere in the case drain line there is a check valve. Is it stuck, creating too much case pressure? Case drain linme clogged? Internally collapsed? Shaft bearing on the pump OK?