Greetings, I'm trying to diagnose why our old 490D quit swinging. It get very little use anymore, and had been ok up until a week or so ago when I went to move some dirt in the yard and do a little grading. It hadn't been used since a septic in March. Symptons: Initially started swinging a bit rough. I checked the oil, and it was low as usual. Filled and operated OK for a while and then started again. Stopped and checked oil again and refilled. I slowly rotated the machine, and it seemed like the swing brake was grabbing instead of easing on. I checked the oil again and it was low. I then moved it and opened the cover to the turntable and there is oil down there. Closed everything back up, refilled the oil and let it sit till today. Today I checked the oil and it was again low. I refilled it and rotated the machine only maybe 90° each way and the brake was grabbing. When I went to rotate it back straight, it stopped moving completely. I can feel and hear the swing motor turning I think, but it's not moving. What should I do first to troubleshoot? I'm not really a mechanic, just a "farm" mechanic mostly, and I don't have any pressure testers, but may be able to borrow a set. Thanks,
Sounds to me like you've lost the bottom seal and maybe bearing on the swing pinion, but it's only a guess..... then something let go in the swing gear. I don't think it's the brake grabbing, more likely a munched up bearing or the gears are chewing metal? You say it won't swing now, with the bucket on the ground, can you track the machine in a hard turn, see if the house freewheels or is locked up? If it was me I would probably remove the two hard lines and the drain hoses off the swing motor and remove it to inspect the output shaft and the planet gears below it, looking for something obvious. Probably have to drain the oil tank first though.....
The 490E I have was losing gear oil daily when I purchased it. I pulled the gear motor and found the shaft seal had failed. Replaced it after flushing (someone had shot grease into the motor lubricating reservoir in an attempt to stop the leaking). While the motor is out, inspect the turn table gears for damage or foreign debris. Not an expensive fix but a lot of heavy work.