Our Hitachi EX60-2 was not swinging at all so we had a service man out who replaced a part within the slew motor. Upon putting it back together it now swings, but does not brake properly. When turning anti-clockwise, braking works as normal, however when going clockwise travel continues after releasing the lever. The hydraulic oil reservoir gauge is dropping when in use and the level in the slew gears is rising up the dip stick as well as exiting the bottom. Obviously the high pressure seal between the slew motor and gears needs replacing again (I did it not long ago). Does any one know of any other issues that may be going on to cause the slew not to brake please? Asking because the repair man doesn't really know what is going on.
Sounds like a poppet or seal is damaged or left out. Another possible issue might include a scored seal plate and piston and barrel assembly.
Good day Alex Please see attached to help with a fix, if the original failure caused contamination it could damage the main valve but I hope this is not the case. Kind regards Uffex
I was personally thinking bad anti-cavitation valve. But that's only part of the problem, you have pressure rise in case leaking into your gearbox. We have a couple issues here. Was the oil migrating prior to the service servicemans visit?
Not sure on this model but most swing drive motors have counter balance valves to slow your swing. If you have hydraulic oil getting into the gear box then you have a shaft seal failure, whether its from wear or hydraulic pressure would need to be identified. If you didn't have the oil getting in the gearbox before, then I would say there is a possibility that the serviceman either installed something incorrectly or left something out during assembly. Maybe the non-slowing swing direction has caused the shaft seal leak?
If the machine has a case drain filter a blocked or restricted filter can result in seal failure as Vtech suggests. KR Uffex