Excavator turntable growling

[Holmes]

 I have a 1995 ish Kubota 12,000 lb excavator that growls and crunches on occasion. It seems to do it around the 1: to 2.30: clock location from the front, but only occasionly. My guess is bearings ,but I do not know what is under there.  I have done a visual inspection and all I see is grease.

 

[deerguy]

Good morning Holmes,

After 20 years working for a bearing manufacturer, I think I might have some useful info for you. Most if not all excavators sit/turn on what is called a turntable bearing in the heavy equipment world, and is actually called a slewing ring by the manufacturer. It has a gear ring on it which meshes with your swing motor to allow the unit to turn under a controlled setting.  The bearing itself has either 2 or 3 sets of rolling elements usually ball bearings or roller bearings and sometimes a combination of both. This allows for applied loads from different directions. The balls/rollers are all spaced with identical spacers, usually made from high grade plastic. I've seen fella's have spacers made from UHMW at a local machine shop.
To remove, u will need to seperate the body from the track frame assy. With any luck, you have a few spacers that have been chewed up and the rolling elements are bunching up. If it does the noise in 1 spot, there is likely ring damage in that area. Worst case scenario, you have ring damage where the rolling elements travel, and the bearing will either need to be repaired or replaced. There are a number of repair shops in the USA and are quite popular even with us Canadians.
Make sure there is nothing that has gotten stuck in the swing area and is making theat noise which has nothing to do with the bearing.... wouldnt want to take it all apart and find an old screwdriver jammed in there somewhere, lol.
If you get some photo's or need some ideas on where to look for a repair job, just eyll and we'll try and help.

Regards, Deerguy

[snowstorm]

thats one thing that you want to greese a lot. my cats always have 2 fittings 180 degrees apart. have never had to change one. might want to look at the turn motor just to be sure its not that. dose it feel loose? lift the machine off the ground with the bucket have someone look for any play in it. if it is the bearing i would expect it to be a several thousand $ repair

[SPIKER]

also check for rock, bearings wedged into the gear on one point then you hit the right pair of teeth it binds up. 

This is ASSUMING that machine had multiple rotation ability as I dont know them.    try it 360 for a couple turns in one direction to check if there is a single point of contact.   and then go a few in the other direction one or two more turns than you went in the first one.     

Then if you find the bind stop it as close to on it as possible and mark all meshing gear points for extra close inspection.

Mark

[Holmes]

I did spin in around 3 times in each direction with no noise.  I would prefer to find a rock or removable problem than to have it be the bearings. I will check it thoroughly tomorrow.

[snowstorm]

dose it only do it when you stop? some will sound funny if it stops quickly

[Holmes]

It has only done that noise when turning. 

[snowstorm]

some may have a swing brake if it dose stopping quickly could sound strange. how long have you had this?

[haywire woodlot]

The swing brake in my ex-60 will some times make a bang if I stop traveling and rotate rapidly at the same time, It seems to happen only if the machine is operated across an incline. Perhaps this will help you narrow down what the trouble is.

[Holmes]

I've had the excavator for 7 years.  The first time I heard the noise, Thursday, I was on an incline , moving backwards and rotating, empty, to see the hillside to my right. I almost never run at full throttle .
It sounded like rocks being crushed against metal and then it sounded like metal against metal. I have not seen any openings that would allow rocks to get into the turntable.

[Holmes]

It appears to be a swing break issue. It is not consistent and happens mostly on an incline.  Thank you all for the help. I am glad it is not the turntable ...