Track problems

[realhardtail]

My tracks on my OC-3 keep trying to walk off at the most in-oppertune times.  I think I have an alignment problem.   My tracks are 54" in the rear and 51" in front.  How do I fix it?  I also was told that my track bushings are wearing through.  I haven't ever rebushed tracks, it appears difficult.  My track adjusters need adjustment but they're froze, that will be addressed when the tracks come off.  Does anybody have some experience with these issues?

[Orangeman]

realhardtail: The fact that you have taken some measurements is good. I would think that you would need to repair or replace your track adjusters first.

Second, I would see if the idler moves significantly if you push on it from the outside. If so, I would suspect significant wear in the idler shaft and bearing/bushing assembly.

Third, I would check wear on the fascia of the idler, is there more on one side or the other.  

Fourth, is drive sprocket on the rear loose. Is there deflection at that location.

I recommend you secure a good micrometer and begin to take some measurements on the undercarriage from front to back or back to front.  

Hope this is of use. Orangeman

[Jack in NB]

Tread jumping on ours was cured with new pins and bushings.

The toe-in is likely due to wear on the track hangars at the back. You'll probably also see the bottom front of the treads an inch or two closer together than the top.

Design flaw. The outer track hangars have (or did have!) shields over them to help protect the rear sprocket studs. The inner ones had nothing, and got a continuous bath of grit. They were supposed to be oiled, but the brackets had only one oil hole, and that was on the back of two of the hangars - so no oil got to the pressure (and wear) surface at the front.

That, coupled with a squirt of oil once a day (maybe!) led to far more wear on the inner track hangars than the outer ones - front and bottom. Also chewed down the boss on the final drive housing. They will wear to the point that the sprocket teeth hammer on the rear lower track roller - even broke one in two on one I acquired!

Net result - pigeon toes! And if you had the old Anderson dozer with the lift cyl on top of the engine, the tracks chewed the sides off the push arms!

Fixing is a labour of love. Took me a week. I built up the casting bosses with braze, made a buckshee lathe (fly cutter) mounted in the axle hole to turn the casting round, and bored out the hangar to match.

Then fitted grease fittings front and rear of each hangar, and greased every couple of hours. Tried to fit a rubber dust shield over the inner hangars, but that lasted only a few hours.

[realhardtail]

Well, I've got it all torn apart, one of the final drives lost a bearing some time ago.  That is mostly fixed, I just need to buy the last bearing that the local parts house doesn't carry.  after a nice visit with a track building shop, I decided I cant afford to rebush the tracks.  This afternoon I welded the all the bushings up on one side (the side that was wearing through).  The pins are sloppy but that makes it easier to keep the pins out of the bushing welds.  I also was encouraged to do the drive sproket welding myself- I was a bit intimidated by the size and precision required.  I don't know what, if anything, I'll do about the track alignment problem.  It is coming from the heavily worn track carriage hanger hoobajubes on the back end, they dont appear to be servicable.  I guess with my track adjuster freed up and the slack pulled up it may just roll that way.  A little camber is good in cars right?
My standards are getting lower for the quality of the rebuild, and I am realizing how little I will actually use this machine in years to come.
I also found a sloppy bushing in one Idler which I intend to replace and 4 wiped out track rollers, at least 2 of those will be repaired.  So far my time zone has conflicted with ordering parts from Zimmerman so i am hoping that he has reasonable prices.  
Overall, It has been quite fun and simple mindless work, can't wait to finish and drag some more logs and see if it pulls better with all the final drive pieces intact.