I know just enough to be dangerous.
-check hydraulic fluid level and if the fluid looks ok (not milky or lots of foam) Top it up and/or possibly replace it as necessary.
-replace the hydraulic filter (with a hydraulic filter, not an engine filter, you might get cross matched incorrectly, and it is bad for hydraulic systems to get an engine filter). If you do this, maybe cut open the old filter and see how it looks inside. Metal bits are considered bad.
After this, I think it comes to inserting a pressure gauge into the hydraulic system and seeing where you are getting pressure and where you are not. I'd start with right after the pump and work from there.
-check hydraulic fluid level and if the fluid looks ok (not milky or lots of foam) Top it up and/or possibly replace it as necessary.
-replace the hydraulic filter (with a hydraulic filter, not an engine filter, you might get cross matched incorrectly, and it is bad for hydraulic systems to get an engine filter). If you do this, maybe cut open the old filter and see how it looks inside. Metal bits are considered bad.
After this, I think it comes to inserting a pressure gauge into the hydraulic system and seeing where you are getting pressure and where you are not. I'd start with right after the pump and work from there.