I don't know a thing about them, but I have a few opinions of dozers I'll share with you. Mine is a 1989 Case dozer, so it's just a little newer than what your looking at.
The problem with dozers are they are worked there entire life and maintenance is questionable at best. Your buying used, so your probalby like me, you can't afford new. I'm not critisizing, but you really need to realize that you are buying a MONEY PIT!!!!
WHen it's working, it's the greatest thing in the world. When it's not, you have the worse headache ever.
You really have to be able to do all the repairs yourself. Nobody wants to come out to your farm to fix your machine. It's not worth there time to deal with a small time client when there is so much work for them with big construction companies and the rental yards. They are basically simple enough to work on, but it's always something new. You have to be able to figure it out on your own and fix the problem.
Do you have a dealer close by with parts? Do you have the tools to replace or rebuild just about every part of it? Tracks come off. It sucks, but learning how to do it when it's in the middle of a bunch of brush and downed trees is the wrong time to realize that you can't pick up 2,000 pounds of track.
Go into this expecting lots and lots of wrench time. Anything less is just silly.
The other consideration is what are you buying it for? If it's some small projects around the place, then you'll save money hiring it out. Only buy if you have a long term need for it.
I look forward to the day when I can sell mine. No way in the world would I want to own a dozer just to have one. NOPE, NEVER!!!!!!!!!
Good luck,
Eddie
