Recently picked up a Hitachi 120-2, previous owner lost swing function during use. He rebuilt swing motor and had local Deere service check pressures, they checked out ok. Unit free swings by hand while all other hydraulic functions work properly (Boom, Travel and Bucket). Could this be a solenoid issue? Not sure where else to start on this.
Good day If you can swing by hand it maybe that the drive is broken since the brake is not holding the superstructure, if you are trusting hear say regarding the pressure check I would be inclined to go over that work. Kind regards Uffex
Thanks for the info, I will re-check the pressures at the swing motor to verify fluid travel.
Pick up the boom and bucket off the ground. Shut off the engine and then get out and push on the bucket. If the house turns, you likely have a broken pinion shaft.
The cab free swings when engine is running, no response from joystick. You can turn cab 360° by hand while all other functions operate. Would a pinion shaft cause this?
It could.
Good day Can you with an helper operate the swing and listen at the transmission for any rotational noise. Draining a small amount of lube from the transmission may indicate some evidence of failure. Lifting the motor you could get a visual on shaft rotation this however may not be conclusive as low pressure may well turn the motor. The logical action would be to plug the main lines with a gauge operate and see if you have working pressure. Kind regards Uffex
As i recall the swing pinion gear is splined onto the pinion shaft. I suspect the splines might be bad.
UPDATE!! Pulled the swing motor and all plates and internals are clean and smooth, shaft is intact with no wear. Reinstalled and still no swing. Placed gauge on feed line from spool valve and had little flow, not measurable on 3500 psi gauge but does visibly flow a little with open gauge hose on both clockwise and counter-clockwise function. Swapped swing solenoid with travel solenoid and still no swing, travel worked as normal. Any ideas?? Spool valve stuck or damaged?? All other functions work, digs and travels perfectly
Good day Troubleshooting document attached. Kind regards Uffex
How is the situation when you do the combination: boom rising and swing? The machine can swing or still cannot swing?
Still does not swing, I have the WinDr cable but the provided disk does not load. Would that help with a diagnosis?
Did you try what JohnC suggested below ? “Pick up the boom and bucket off the ground. Shut off the engine and then get out and push on the bucket. If the house turns, you likely have a broken pinion shaft.” . With the engine SHUT OFF it will guarantee the swing brake is applied (assuming it is functioning correctly). If it swings when you push on the bucket you know you have a broken pinion shaft, or planetary carrier splines stripped out at the pinion shaft in the lower gear box or the swing motor shaft is broke.
Please see attached images
Sometimes the pinion shaft, planetary carrier or motor shaft is not damaged, we can still push to rotate the upper structure. I'm sure it's true, there have been such cases in fact.
I've been told that some machines in Asia don't have swing parking brakes. Is that possible?
It's true!!! in case the friction disc is too worn and of course, at the same time the pistons and cylinders of the swing motor also wear out this phenomenon can also occur