Hello everyone, My name is Richard and I'm currently restoring a Kubota KX36-2 mini excavator that I bought as is. After replacing all the bushings and axles on the boom, which were very worn, I realized that the slewing ring bearing has a lot of play and needs to be replaced. I also noticed significant play in the cab's rotation, and I disassembled the rotation motor to check the condition of the pinion. It shows signs of wear, but I don't think this wear is the sole cause of the play. When I turn the pinion by hand, I find the play in the rotation to be significant, but I don't know if this is normal. I made a short video so you can judge for yourselves : Could someone tell me what they think? Thank you very much!
Could be wrong but that doesn't look to bad but can't see the pinion gear and the ring gear. That's more than likely we're the movement could be coming from. It's usually the most neglected part of any excavator.
I have a new Eaton swingmotor for a demolition grab in my workshop its not the same as your Sumitomo-Eaton but close enough. I have checked the play of the pinion today and it appears to be less than yours, maybee 50-60% of yours. Inside the swingmotor there is drive shaft that connects the hydraulic motor and pinion. This drive shaft have splines in both ends and I have had problems with wear on the splines on the pinion side, thats why I have a spare unit. The play in your pinion is a lot less than what i have seen on my pinions so if you have wear on its not much. There are two problems with wear on the splines inside the swing motor. 1. Wear means metal debrise inside the case whitch will accelerate the wear fast. 2. The swing motor is lubricated with hydraulic oil and every time you stop a swing motion the make-up valves in the hydraulic motor draws oil from the case and the tank return line. Eventually you will have metal debrise in your hydraulic system. If you are worried I think its a good idea to take it a part to check it and clean it.