I run a Cat 140M all wheel drive grader and after 2400 hours the Top front wheel drive kingpin bushings are wore all the way through to the metal. The Cat dealer says it wasn't greased and will not back it up. It has been greased more often than the required 100 hrs. or two weeks. there is grease everywhere except the top kingpin which is very sloppy and the grease got pumped out. (it's the easyist one to grease and it was). It is run on very hard rocky roads with lots of impact and shock and I believe this is the cause. Has anyone herd of this or have any knowledge about this? Your answer will be greatly appreciated.
Hmmm... I operate a 140M and grease it regularly. No problems with the kingpin. I have 2400 hrs on it, you may be right.