We are replacing the steel ball bearing and the plastic. Since the machine shakes if it had a load on the bucket. What do you call the plastic? I used spacer and separator keywords in google but can't find any info. If I can't find that part... What kind of plastic should be use to fabricate it? POM/Delrin or UHMW-PE? See attached Pic. Thanks in advance, wax Some background info: Mitsubishi MS120 excavator. Turntable is interchangeable with MS110's bearing. Bearing was made by NSK. But local dealer don't sell or service them. We got an used bearing from a MS110 but the shake got worst even without a load.
bearings are they called ball and cup by any chance
The "plastic" is could be urethane. It's used for a lot of bushings. That's my guess anyway.
Are you speaking of a turn table bearing? It is also known as a Rotec bearing or a slewing bearing. I have never seen where you could buy the balls or the seperators. The thing that usually goes wrong is the races start spalling off material. You can check this by using a dial indicator and checking up and down movement in the bearing. Good ones usually have .030 - .050 up and down. I've seen ones over 0.100 still being used but they didn't last long after that. If you can't source a whole new bearing you are probably about ready to cut out the machine. There are after market suppliers but your machine might be a rare one and no one makes that configuration anymore. Good Luck!
Yes John, Slewing bearing... when you say "up and down", do you mean vertical up and down? 0.1... is this in inches or mm? Mitsubishi Heavy Industry's excavator department was sold to CAT about 20yrs ago, which I didn't known at the time of purchase.:Banghead From what I gathered, the new division only builds small excavators.
Sorry, I wasn't paying attention to your location. The measurements are in inches and yes they are straight up and down. The MS120 should be the same as a E120 Cat or the SK120 Kobelco. You might do a search on the web checking for suppliers in the United States. I'm sure there will be someone here that could source a new bearing. Good Luck!
turntable bearings Hi... CSC parts in California sells mitsubishi slew rings. their web site is "turntablebearings.com" give them a try, they carry Avon bearings I believe. good luck Dave
The swing bearing is NOT the same as the Kobelco SK 120, Different company. It is the Cat E120 which replaced the Mitsubishi brand. SCM in Japan basically builds all models of the Cat excavator. Some are build in the Belgium plants, but there are designed in Akashi Japan. Before I would continue with this direction, have you actually measured the up and down movement. New would have been around 1mm or .039" with 2.5 mm an upper limit. Excavator bearings are NOT tight and cannot be due to structural flexing that is normal on an excavator. The other thing is that these balls are VERY hard and so basically do not wear. Take a close look at the inner and outer race of the bearing. I would suppose that you will see flaking of the hardend roller paths where the balls roll. This basically cannot be repaired. The above movements, while to some might be distracting, will not hurt the machine or operation. Just a thought before you waste a lot of money. While is MIGHT be possible to find oversize balls, if the race is beginning to flake off, you will not see a huge increase in lift of this bearing. Good Luck
It might be just me , but it sounds a little strange . The used bearing that was fitted would have been checked right ? The machine it came from should have been at least tested before it was dismantled , if it was going . Someone would have given the bearing a spin or a push with their foot before it was bought/sold . It's hard to believe two bearings would have exactly the same problem . Is it possible the slew motor has got a bent pinion shaft or the pinion gear or crown wheel has a tooth or two missing causing the vibration ?