This old girl presents her self at the workshop with a great deal of free-play between the undercarriage and the top of the machine.
Close examination reveals that the slew bearing has lost the plot. The grease line or tube that feeds grease to the ball-race in the slew bearing has come adrift. For some time now there has been no lubrication to the bearing. That I guess means wear, yes plenty of it.

Step No 1. Remove the digger boom. We have found it is always handy to cap all the hydraulic pipes and colour code them with cable ties. This makes assembly a real  treat.

Next free all the bolts and hoses that mate the machine to the undercarriage. Here take care not to forget even the smallest of hoses, including the cause of the problem, the grease line to the slew bearing.
Sling the machine, and up and away we go!

Photo view of the underside of the machine. Notice the slew drive gear poking it's nose out, we have another post on this type of repair. Click here to go to it.

With both parts of the excavator safely on the ground again we can start with the really dirty work. On this machine the slew drive motor also has to come out. This is because there is just too much "slop" or free travel between the left and right control.

So here we are, the slew ring still bolted to the undercarriage.
In the centre we have the rotary
Nathan's finger points to where the bolts that secure the slew ring to the undercarriage should be.

Yep! they are there! With the aid of the impact driver they all come out and the slew ring is free.

After cleaning the slew ring it became evident that not only did it not get clean fresh grease, it also had a great deal of ingress, dirt, mud, water and the like. Because the grease was not being replenished all the time , this ingress became a toxic form of grinding paste. Soon the slew bearing collapsed, with some of the balls in the race not even turning.
The only solution , a new one OR a refurbishment.
We opted for the latter and that was carried out by a professional Bearing Dealer.


Two weeks later we are back in business ,this time we are in the assembly game.

All cleaned up and painted, the undercarriage is ready to be mated to the machine.
Here the slew bearing is not fitted to the undercarriage. It is waiting in the background with the grease gun.

And there you are, one slew ring bolted to the undercarriage.

Stand clear, here comes the forklift driver, with the top part, heavy but well balanced.

And down she goes, nice and slowly, that's the way!

Nothing to challenging about this all, "To easy Mate" as we say here in Australia. Just look how relaxed the forklift driver is.

bolt down the slew bearing, connect all the hydraulic pipes that you marked or tagged up front, connect the electrics and yes last but by no means the least - the cause of the problem - connect the grease line to the slew bearing!

Enquiries regarding this type of repair are welcome.

Call or text Charlie on 0403 861 597

You are also welcome to contact us on the form below.                           

1 comment: