when you say 'rest of hyds' works good? does that mean it has a top cover remote that works fine? or does it have a front pump that is totally UNRELATED tot he rest of the hyds.
if it has a top cover remote that works good.. then the pump and fluid level are fine.
ont he 3pt.. make sure you are in position control, not draft mode. ( lever up )..
if it leaks down when parked.. it likely needs a new oring and washer on the lift piston
might need some new orings on the cyl block.
kit is less than 20$ for the top cover.. etc..