Backhoe Swing Issues

[SSdoxie]

Another possibility is the port relief valves in the swing circuit. These are set a few hundred PSI higher than the pump relief so it takes an external load or the inertia from swinging fast and stopping to open the relief. If the relief poppet for one side got stuck open or was leaking, then oil pressure would be dumped to tank and it would not have much power in that direction but it would have power in the other direction. There are also anti-cavitation checks on each port, that if stuck open would do the same thing. The check and relief is part of the same assembly that is screwed into the valve and it may be worth pulling them off for inspection and cleaning.

This would be the more probable explanation if it regains function after free swinging it a few times. Free swinging it forces more oil through the port relief and that movement eventually cause the port relief to pop closed, reseat. Question is why does it stick in the first place? Either the spool inside port relief/anti-cav has some scratching make it stick, machining in the valve casting could be rough so not seating properly, or debris/contamination in oil getting stuck in the relief.