100 series track alignment issue

[farmboy186]

Hey everyone, Im having huge problems on my 1976 John Deere 300s track to stay in allignment, iv done all new drive and rear idler bearings, and still the track wants to wander to the left (when sitting on the seat), I got frustrated and tried to slam the sled off the ground a couple times and now wonders to the right. the left side plate for the rear idler bearings contacts the sled a bit but nothing to concerning since it looks like just a bit of a bur, any ideas?

[HoosierDeereMan]

I start out buy measuring the length of the track tension adjustment bolt on both sides. Tighten or loosen one side or the other to get them as close to the same as you can. Then jack up the rear of the sled so the track is off the ground. You can start it and spin the track with the engine or you can remove the drive belt and rotate the track by hand. I prefer the by hand method as you can feel the bearings and the bogie wheels as the track moves. Watch the rear of the track alignment as you rotate the track. The track will pull to the side with the least tension. So if it's pulling to the left, tighten the left adjustment nut a half a turn. This may take a few tries but you should see the rear of the track correct itself and stay centered. Once you think you have it. You can start the engine and run the track at clutch engagement speed just enough to spin the track under power. You can double check the alignment and verify correct track tension according to the manual.

Troy

[JDT]

If you are sure that you have checked everything over with a fine tooth comb it is possible that the track is bad.

But before you pull it, recheck your drive shaft bearings and the shaft itself. They are often worn or shot. And the idler bearings.

The two tracks that I have seen in the past that were in fact bad would align on the stand and stay in place when rotating by hand but when you actually put the sled on the ground and drove it only a few feet and than stopped and looked it was back rubbing on the side.

I think what happens is the reinforcing strands or fibers in the track break or get stretched out. You align it perfectly and then when you put power to the track the rubber stretches only on one side and then tracks off.
I actually removed one track and revered direction on it and sure enough now it tracked to the opposite side under power. In my book that proved that the track was bad.

Only seen it twice and both tracks looked fine.

[farmboy186]

this track looks fine replaced both rear and front bearings iv tightened the track evenly but when you start to rotate it pulls to one side, i adjust the side and still slips over so i tighten it more, i was wondering when i replaced the one rear idler if it wasnt correct and maybe i need to repack the idlers since i replaced the center one ( you can see ware on the track in the middle from the old ilder)

[JDT]

Are the idlers all the exact same diameter?