Have looked in the archives, probably something there I overlooked on how to change the seal but haven't come across the right thread yet. Unclear about needing to break the track or not. A u-tube video would be nice on this! '67 model, 78A7177 Guy I bought it from runs it for six years, no problem. Three hours on it today and I'm back here lookin' for help.
Headed to the orchard to see if how the track tensioner cylinder is removed has suddenly become self explanatory. Of the two online sources located so far, one says to remove one side of the yoke and lift cylinder out, the other says to open the track, roll the front idler forward and then remove it.
Depends on why the seal blew. Maximum extension adjustment is 5.1" Manual will tell you to split the track. Here's what your getting into....
Mine is different than the drawing. The chromed shaft/piston has a bolt flange that fastens to the wish-bone with four bolts This flange also contains the grease zirk and relief valve. Once unbolted and pushed to the rear a mother load of grease dumps out from inside the chromed shaft at the junction point of the head/flange and the wish-bone. Must be a seal or gasket in there as there no evidence of grease leaking until it was unbolted. Found the master link (I think), has a dimple in the end? It is positioned right over the front idler at the moment. Both ends of the pin are welded... begs the question, how does it come apart? The wish-bone front ends bolt to either side of the front idler, the back ends sandwich a largish pin that has the fore mentioned flange to which the adjuster flange bolts. Depending on how long the adjuster rod is, it does look possible that by removing the outside half of the wish-bone one could pull the adjuster out. Bet those bolts will be a treat to loosen. The other track has what appears to be a replacement piston. Took a measurement of the exposed shaft from the back of the bolt flange to the end cap on the spring; Five inches. There is an o-ring floating on the outside of the shaft, dirt collection deterrent maybe? The tracks are obviously well worn on this thing, just new pins (could they be rolled over to wear on the other side?) would make a world of difference in the adjuster travel used. In any event, is it acceptable to fabricate a pair of 1/2-3/4" shims to place between the wish-bone and the adjuster to leave some travel.
At 5" extension your tracks are beyond salvage. You can shim the wishbone at the idler or remove a link and run them to destruction which will occur at a more rapid rate as the track pitch gets longer.
The master pin shouldn't be welded by design, it simply presses into the corresponding link. Maybe on your tractor the pin started to "walk" out and so it was welded to keep it from moving..? To remove the pin you're going to have to grind off all the weld before you can drive the pin out. What you're seeing isn't the pins, it's actually the bushes. If caught in time pins and bushes can all be pressed apart, rotated 180, and reassembled. This process is known as a pin & bush turn. However if there is as much wear as you say in the tracks it would appear on the face of it that your links are past that point and only good for scrap. As OM says the generally accepted solution for tracks in this condition is to either remove one complete link from the tracks or shim the wishbone at the idler to take up the wear and then run them to destruction.
It is being used it an orchard to do minor dirt work, at the moment, a pad for a metal building. Might cut a creek crossing, some walking/4-wheeler trails and maybe clear for a deer food plot or two. Maybe after working it 20-30 hours if it is none the worse for wear, it might stay for a while, if it is constantly being worked on instead of worked it will be passed along. New batteries, fluids changed, linkages nice and tight, new seats... oughta bring fair $. In the mean time, to serve my most immediate needs, need to figure out how best to remove the adjuster shaft/piston so my building can go up on schedule and before the next rain makes an unholy mess. Guess I will try splitting the wish-bone, shimming and leave shortening the track until after the pad is done.
The whole machine could be completely rebuilt but unfortunately on a crawler if the tracks are worn out affects the price more than everything else put together unless it doesn't run or move at all. Needing a complete new undercarriage is the first thing buyers will/should look at. A compete new undercarriage is in the $10K range. Maybe you could find decent used undercarriage?
WD- Near as I can tell, the drive train is fine. The overall appearance is okay, the previous owner put new NAPA batteries in the day before I looked at it. The obvious faults (seat, tightening the controls, fluids, filters, cleaning out the belly pans) and now putting some adjustment back in the track adjusters are being tended too. The tracks, well, I didn't know what to look for. Have a total of $4500US in it, so spending a few hundred more still leaves my expenses under having the work done by someone else. Plus, I can still sell the machine at the end of the day, which is what I was eluding too by "bringing a fair $". EDIT: Was it your post a while back detailing the removal of a track link to put the adjuster back in range? Making a shim is quicker for me right now (and within my comfort factor, I have never worked on crawler tracks) but once the immediate panic is over the plan is to look at doing just that.