Undercarriage questions?

There are probably several different scenarios where components that have been worn in relation to other components that are not worn out, may be worth doing some repair work, replacing or building up of components, before it is allowed to go too far, where you might as well run it to destruction.

There are some things that will accelerate wear, like the track tension being too tight, machine is kept running on worn components, say the pins/bushings are worn, still ok internally with some wear, but they are not turned, they will eventually ride up out of the root of the sprocket teeth and up closer to the point, pitch changes and the wear is accelerated to the sprocket, and many times when a sprocket might be worn above the root, getting the pitch back, byt turning the pins/bushings or replacing will put the P/B back in the root and the sprocket most likely is ok to use as the wear when higher on the tooth is not where P/B rides anyway once the pitch is correct again. Lot of variables with this. Say the rails are worn, pins bosses are hitting the roller flanges making for a bumpy ride and accelerated wear, time to deal with it or cut the roller flanges off and run to destruction, you will get some time from doing this, but at the end everything will be worn out.

It's nice when you can monitor U/C from new, or when a machine is new, always affording time to decide what to do, planning ahead to do the work needed at wear intervals to avoid accelerated wear and keep costs down, until you have actually worn out the tracks after getting max service life, vs just run it until it breaks mentality which may not get you the max service life.

You should assess what you have, and see what it will take to get you some extended service life, you already need pins, bushings and links, possibly sprocket segments or sprockets, (not familiar with that tractor), track pads being good, you need new bolts and can re-fasten your pads to the top of the new links (making sure there is no paint between pads and links when doing so or they will loosen up), you need to measure all bottom rollers, idler and carrier rollers to see where they are at on wear, running like it is will most likely accelerate wear rates to them, but if they are also well worn, it could be time to run to destruction. Excessive tension on that track to keep it on, I would suspect as being the worst thing and would want to deal with that before doing any work with the machine. I am not sure what kind of problems could be associated, but overly tight tracks will cause rapid wear, who knows if it will magnify any shock loads to the finals or track frames. ALso make note of any odd wear or things that point to the track frames being mis aligned, another wear rate accelerator.

I'm not an U/C expert by any means and maybe not all would agree with the above, (mostly from observation as an operator) but I have seen and experienced enough to at least have a good understanding, I think :) ! I have seen and been on D8K's run til destruction, we had a Fiat Allis FD30 slipping the track on the sprockets, but the U/c was not completely shot, have brought same 8K's to CAT for complete U/C's remember bringing the 977L in there for U/C work too, caught it in plenty of time. Have run D5's and D6D's with new U/C's to ones almost completely worn out. Some outfits doing landfill closure jobs I've been on would run their D6 hi tracks until they flung the track pads off, 3rd gear both ways doing max production work in high gear with operators just hammering the tractors certainly increased the wear rates. On sub division jobs, using the small grading tractors D3, D4 sizes, some of the guys would really pride themselves on how fast they wore out a set of tracks, doing finish work working in tighter areas with lots of turning or slopes. Soil types, poor operator habits, lack of maintainence, also play a significant role in wear rates. Some operators and types of work are really hard on U/C's like sand or rock. I used to set up for a nice K pattern when loading trucks from a pile with crawler loader, to minimize the wear from sharp turning, assuming it was good practice to work like that, loading for awhile from one side then switching the other.

I would think that if you were to put a new U/C on that machine those CAT sealed and lubed track chains would be worth it, but not so if you don't plan on starting over with new or built up components to get everything close to new, you are close to running to destruction now, you probably don't want to mix new expensive components with older worn or close to worn out ones. It's never easy, especially for a small operator, I can remember the bills for the work done on those 8K's at CAT, never less than $30,000 and that was over 15 years, can't imagine what it would be today.

Rails can be built up, but if your pins and bushings are worn internally, might be feasible to get the entire track chain, with rollers itused to be prevalent to build them up, not exactly sure about the details, you can't overheat the innards, there was machine equipment that would keep them cool, have seen where people immerse 1/2 of the roller while welding, idlers can be built up, you would have to talk to someone who runs or has experience in a track shop, building up components may be possible, but unless you do it yourself it may be cost prohibitive.