David, what is the pressure on the up side and the down side. When the gear is in the retracted position on jacks does it stay up or does it leak down. The most common problem is the gear up check valve, when it is bad the gear will leak down. The pressure is easy to adjust.. I am sure your engineer could do it all with instructions.
I am assuming that you are not a 114B, the24 volt system, that uses an entirely different pump.
If you were at my hangar with the pump I could show you how to fix it legally but I can't do it for you. I have all the parts in stock. They are a great pump once you learn how to work on them.
If you want to have your maintainer give me a quick phone call I can explain to him what tests he needs to do and how to do them, then we can go from there. My moblile is 229 407-0200
Ken