stuck track tensioner on '85 JD dozer

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inlaw123
MC crawler
MC crawler
Posts: 1
Joined: Thu Jun 23, 2022 7:14 am

stuck track tensioner on '85 JD dozer

Post by inlaw123 » Thu Jun 23, 2022 4:50 pm

Because the left track tensioner on my '85 JD dozer wouldn't take grease I decided to collapse it by removing the grease fitting, the plug next to it and the ball, by placing a large wooden block between the blade and the track and moving the blade backward. Grease shot out of the tensioner and the tensioner collapsed to the point where about 1/4 inch of the chrome was still showing. The tube itself had rusted from that point back.

I took the pressure off the track, replaced the grease fitting [with a new one], the ball and the plug and attempted to put grease back in the tensioner with a grease gun. It wouldn't take any grease at all. I got a grease fitting cleaner, filled it with about 1/2 oz. of solvent that came with it and used a small tack hammer to slowly tap the cleaner into the tensioner through the grease fitting. I did this 7 or 8 times but the unit still wouldn't take any grease.

Next I put a heavy logging chain around the tensioner just behind the idler and wrapped it around the blade. I took a 2 foot pipe wrench, put it on the tube just behind the track roller and had a 300 lb. guy stand on it while I carefully operated the blade forward. It pulled the tube right through the pipe wrench leaving a small pile of metal grindings. We tried this a couple of times after adding more grease solvent into the adjuster.

Next, I let the pressure off the chain so that the track was completely relaxed and I drilled a 3/8 inch hole through the tube just behind the track roller and put a 3/8 in. bolt through the hole and tried it again. This time it broke the log chain so I got a heavier chain and it broke that one too. It almost sheared off the 3/8 in. bolt as well so I took no further action. It is as though the tube is welded to the adjuster.

Since the chain is not pulling in a straight line with the tube itself, I also put tension on the chain with the blade and then used a heavy iron [Arkansas toothpick] bar to pry the tube back and forth in all directions to see it it was merely binding from the angle of the pull. No luck there either.

I'm surmising that I will have to remove the tensioner and take it to a machine shop. Fortunately the removable track pin is right above the track tensioner so I don't have to move the dozer to get at it--not a job I really enjoy getting into AGAIN.

I've had this dozer for about 20 years and it is in pretty good shape. I used it to put in my drive roads around my property when I built my house but mainly use it for snow in the winter. We're all the way up on top of a mountain in western NC and its a 2 mile run down the mountain to get to the highway. I hope someone has some good ideas on this problem. I'm 83 and am not thrilled with the idea of heating and beating that pin out and all the rest of the crap that goes with it.

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: stuck track tensioner on '85 JD dozer

Post by Jim B » Thu Jun 23, 2022 5:21 pm

Welcome to the site.

Have you tried pumping grease through the new fitting with it not in the adjuster? I have had some new fittings that apparently don't have internal clearance enough. When you pump grease into the it seems the ball moves to allow grease in but moves enough to close the passage through the rest of the fitting and they act like a plugged fitting. The fluid in the fitting cleaner might go through as you tap it, but the grease from the gun is too much too quick. Just something to check. Usually, you can exert more force with a grease gun than the blade, so it is more common they are hard to push in, not move out, unless it tore the seals moving in.

As a bit of housekeeping your "85 JD dozer posts should be on the Late Models Board. Don't be surprised if a moderator moves it over there. That board is for the machines starting with the 350s and 450s and newer models. It would be great if you told us what '85 JD dozer you have, sometimes things are different on different models.
Good luck on it.
Jim

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