recently purchased , when i bought it the loader would lift frt wheels,now it barely will, seems to lift bucket ok, changed hydraulic filter, was low on oil when i bought so added more, seems it has a 2-4 controller and the front left port seeps fluid when under load, need to fix, it has a screw ,is the screw for pressure adjust ,,is there an o ring possibly leaking, i am sure i missed some info ,i can advise, any help appreciated thanks in advance