ONE WORD OF CAUTION BEFORE I SAY ANYTHING ELSE. If you are taking the thing apart yourself, and the recoil springs are broke, even if only in one place, CUT THEM AT EVERY TURN before even trying to take them out. The left one on the 977 I'm working on now was broke in 7 places and still had tention on it until the third cut. If the through bolt is broke/bent, etc, etc then cutting them is even more mandatory. They are compressed with 'A FORCE OF SEVERAL TONS' (CAT's description of the assembly process) so they can jump out with enough force to KILL YOU if ALL of the force isn't released from them before working on them.
Now, bad as I hate to say it if your looking for used U/C parts for anything, good luck. What I've found over the years is that so many people rate them differently so a set they say is 95% might only be 75% on a good day, be it from a reputible junk yard or from an individual. Because of that pics, and lots of them, are a must before you commit to buying anything used. In those pics get them to include a ruler for things like the height of the track rails, or any other known wear part where it's possible so you have some sort of a refference. I say that because really good scammers can take the pic from an angle that makes the part look good when in reality it's shot. Too when it comes to pricing, remember your paying for them to take off a used part, often clean it up and paint it,etc, etc, so that labor cost is added into the actual price of the piece your buying. Too your paying shipping on top of that. I guess what I'm saying is that if your planning to keep the machine and use it for any length of time, especially if your using it to make money, your better off to bite the bullet and spend a little bit more for new rather than going with used. In the case of the 977, for example, I can get new/rebuilt idlers for about $1000 vs getting a set used that are maybe at 50% for anywhere from $400 to $600. Either way the shipping cost is gonna be about the same, but with the new/reman stuff I'm paying for the life extension of the part, not just for the cost of them to take it off and clean it up.
In the grand scheme of things the labor to put on half used up parts will be the same as it is to put on brand new parts so in the end the extra $1000 dollars, or whatever, for the new parts will pay for itself in the end.
Now if your dead set on finding used pieces your best bet is to get on sites like the machinery trader, equipment trader, etc and find places that are parting out a machine like yours. Look for the ones showing the latest update first as they are the most likely to have machines with the parts you need still on them.
That said, based on what I've been running into with the parts I've been looking for on this old 977 CAT there really doesn't seem to be much variety in the aftermarket nowdays. I say this because out of all of the places I called looking for a set of track rails, ALL of them were able to find 'one set in Texas'.
I can say that nearly everyone I talked to has said that Berco has gotten to where they are doing so many OEM undercarriages that they have priced theirselves out of the aftermarket in most cases. In other words you can check with their dealers but expect to pay a premium price.
Now the best prices I was able to find on new/aftermarket stuff, at least as far as the rails, was from Heavyquip. They were $300 to $600 lower on their price on them than anyone else I talked to. In talking to the sales guy, Scott, I found out that Heavyquip is a 'sister' company to the actual Mfg they sell for so they tend to get better pricing than the other dealers and as a result can pass along the savings.
The rollers on this machine were in pretty good shape so I haven't been looking for them but I did have to have the recoil assemblies. For this machine I found the springs alone for like $250 each from a place that deals in CAT aftermarket, but in this case the whole assembly was screwed up meaning each part would have had to have been bought individually and assembled. To do that takes special tooling that I really didn't want to spend time fabricating unless I had no choice...not to mention assembling one can be extreemly dangerous. As a result I did some more calling and found some already assembled for $700 apiece. I've got those coming from Chartrand Equipment. They are already assembled, and in this case that includes new track adjuster seals, and are ready to set in and bolt up. Wether they have any for your machine I can't say but I got the impression they keep a pretty fair stock on the common stuff.
Beyond that, like I said, it's a crap shoot finding anything used that's in good shape. New, on the other hand, is just a matter of calling around and finding who has what you need at the best prices.
From there all I can say is good luck and if you need anything else feel free to holler at me again and I'll be more than happy to help out in any way I can.
Wayne
Heavyquip
Machinery Trader
Equipment Trader
Chartrand
