Would kind of grind to a halt when swinging. It was not consistent on where it stopped. I swung it until it hung up and left bucket up a little off of the ground with a safety chain. I could swing it a small amount by hand so swing bearing seemed fine. When I pulled the swing motor the planetary housing came with it but it immediate swung to the limits of safety chain. I figured it was the swing brake at that point. Pulled that apart and it all looked good. When I inspected the planetary gears I found one of the sun gears on the lower planetary had ate up bearing. And ruined pin. Gear was not available through deer so I ordered the pin and thrust plates. I took the gear to machine shop and had them press out the bad bushing and make a new one for it. Reassembled and symptoms are still the same. Is there a way for me to check and see if its loosing pressure to swing brake? Could it be something locking up in the swing motor itself?
Typically what stopped the swing on these AIR (As I Recall, subject to CRS, Can't Remember Stuff) is actually the hydraulic motor and the counterbalance valve, then the brake comes on after a short delay, there should be a restriction in the hydraulic feed coming out of the brake someplace, maybe that block bolted on the side of the case near the brake. See the two relief valves cartridges in the motor head with the rubber caps on them? I think they're part of the counterbalance system. Motor could be coming apart also, piston setup...
Good day You may find the attached helpful. Kind regards Uffex
So I had this theory that debris from the sun gear bearing failure had contaminated the bottom bearing so I pulled it all back apart. But I can't get the pinion gear shaft out. I did get a snap ring off of inside but its not budging.
That's because you need a 100 ton press. Even then it might not come out. I have even had the housings break trying to press those buggers apart. So now I don't even put them into a press until after I have sliced the top bearing inner race with a torch.
Wash the bearings out with solvent or brake clean and see if it spins free or is crunchy....
Ill try cleaning that valve before i reassemble, yes, we ended up slicing the bearing race to get it to break free.
So my theory was incorrect. New lower bearing and seal. Cleaned and inspected everything else in planetary. I'm thinking it time to clean valves or check pressures. Twice I've locked it up and had it swing free when slewing motor was unbolted so I'm still discounting the swing bearing being my issue.
Take the brake plates out of the motor to test it.
I didnt find any problems in the valve and the symptoms persist.
the first time I pulled it apart I pulled the brake apart and everything looked great. Are you saying to reassemble it without the plate so that I can know that it is the brake malfunctioning?
If Reassembling with out the brake plates stops it from sticking then it's either a problem with the brake or the brake solenoid
And if not, then motor? Is the control spool an open motor spool? I didn't see a counterbalance spool in the parts breakdown?
I feel like it gets worse the more I play with it. I'd like to understand how the system is designed to work.
What are these?
Should be crossport relief valves. Could be part of a counterbalance (hydraulic brake and lock) setup, not sure.
Sounds like those could be a part of the problem.
Bad cross port valves would cause slew to drift not stick
Are you sure that the turn table bearing is good have you checked it for play they can bind up if they are going bad might not happen when you swing it manually a little
twice i have taken the swing motor off while it was bound up and bucket in air. Both times it freed up and swung into my safety. I can try swinging it farther manually to see if it binds up. Also, when its bound up I can push on bucket wit my hand and feel the slack in swing drive. I put a pressure guage into the top of the little valve bolted to side of swing motor. Seems to be pilot pressure. 500 static and 800 when trying to swing but locked up. It hits the same 800 if I bottom out crowd cylinder. My cell is 619 889 1589
I've got an extra zero in there its 50 and 80 psi. I moved the guage to bottom hose and pegged 500 psi guage. Put in 10,000 psi guage and im showing about 800 on bottom hose.
Ok i was able to tap into brake piston pressure and it swings good anytime the pressure is 500 or better. To get that I need signal pressure at about 160. When its down around 80 or 100 I'm not showing any brake piston pressure and it won't swing. Sometimes when I fire it up ill get as high as 250 signal pressure and slewing works normally. I've tried cleaning a filter in pilot system but made no difference. I feel like there is a screen or filter plugging up somewhere in the signal circuit.
Well, it sounds like you've narrowed it down....