Hello, I'm looking at a D4D, around 1970, and I don't know a thing about crawlers. I have a few old tractors, the closest thing to a D4 I have is a 1925 Fordson with a Trackson crawler conversion, and that's not close at all to a D4. The one I'm looking at seems to be in fairly good condition except for one problem. I'm making up my own terms here so bear with me. The soil shields on both sides are gone and the very large springs on the track tensioners are both broken. Is that a common problem? Is it a sign of abuse? Are there any other problems that are specific to a D4D I should look for? Thanks for your help, ruff

I think first I,d see if I could locate a guy with lots of tractor knowledge and go with you and take a look at it.Post just where your at there and maybe someone on here will come forward and give you a hand to do the checking who is in the area close by.It is a little odd for both springs to be broke but as you may have said that abuse could be the answer. Don,t try changing them yourself if you do buy it as they are very dangerous to change and it takes some know how & a press to do it right and some specs on the spring tension going back together. At the dealer our welder sometimes welded a couple bars across the end plates to hold the spring in place till it was put under the big press and then they were cut off and the spring released. Also the welder sometimes just cut the spring in pieces to release the tension and then the other parts could be removed from the tractor.

Thanks SJ. Is the removal of the springs the dangerous part? If so they are broken already so cutting them more with a torch would be a good way to release tension. I searched the forum for spring tensioners and found a post about snow getting in the works and making the spring slam as the snow breaks up. Could that be the cause of breakage? I live in Maine and this D4 has a big winch on it and a cage with bars across the top so it was probably used to pull logs out of the woods. And I know loggers like working in the winter on frozen ground a lot better then on mush during mud season. So I would bet this one has seen a lot of snow. I do have an older friend that knows a lot more about these these then me, so I'll get him to take a look at it. But it's always good to hear what someone with expierience has to say.

It,s hard to even guess what caused this tractor,s springs to break as I,ve seen them break in the middle of the summer so as we used to say it,s metal fatigue I guess. It,s a very good idea to get the gentleman to help you look at it and give you some more info. as to where to go next. I,m sure the snow could have contributed to their breakage but now is the job of repairs to them if you purchase the tractor.If the guy is handy he can check over the rest of the tractor condition for you as to where you,d need to go if you do buy it.

If the machine has seen abuse, be sure to check the frame rail to bevel gear case connection flanges and gussets for cracks and repairs. Get the serial numbers for the tractor and engine.

I have a D4D direct drive from the mic 60's that I have done extensive work on, including changing one of the springs. The key thing you need to attempt such a project is the service manual. I followed the procedure outlined in the shop manual and completed the job without losing life or limb. It can be a dangerous job not to be taken lightly! As I recall, when I did the job around '96 Cat wanted $600 for a spring, but I found an aftermarket spring from Surplus Tractor for around $200 or $300. As previously mentioned, having a seasoned crawler-man look at the machine would be a very good idea. Another thing you could do is drain the oil out of each of the final drives, transmission, and bevel gear case into a clean pan and inspect the used oil very closely for metal particles. If any "chunks" come out, you are looking at some major time and money to repair. I hope the machine is direct electric start, as the side mount pony engines used on these d4's were a major pain in the rear. I converted my tractor to direct electric start.

Good Luck,
Rick

Great advice. Just what I wanted. The motor is direct start. I'm going to have to think this over. I don't really "need" this machine, but the fun of having a Cat would be great. And I do have a summers worth of jobs for it. The asking price of $3,500 isn't going to break the bank, but the cost of a lot of replacement parts is not something I would like. I keep trying to rationalize it by saying I would buy it, fix the things that need fixing, the springs being the biggest, paint it and sell it in a few years for a little more than I paid for it. Gonna need to think on this. I'll post a picture when I go back. Thanks, ruff

"but the fun of having a Cat would be great"............PRICELESS:D go for it;)

Good luck Ruff, and welcome to the crazy guys with yellow fever. LOL John

The price sounds very reasonable, providing the running gear is 50% or better, and the only major work required is the springs!!

Go ahead and buy it......you know you want to!
Rick