Buying Advice 1968 JD 4020

[TheKuhnFamily]

We're considering a '68 JD 4020 diesel.

I know their John Deere's most popular tractor ever made, but I also know everything has it's flaw's.

What should we look for, or look out for, when going over this tractor before making an offer?

 

[MIKE R]

They are great tractors. I have heard of many of them getting over 10 000hrs without a engine rebuild. I would take a look at the hydraulics, hot well it starts cold, what the oil looks like, does it smoke,... More general questions about how everything works. If it looks to have had a lot off use but the hour meter says different I would be cautious as some one might of turned it back.

 

[jenkinsph]

A few things I would look at, how it shifts through all the gears whether syncrorange or powershift. Should be able to look at the clutch IIRC, and try it out with a good test pull. Hydraulics test with a pressure guage, should be about 2200psi, test position control on 3PH, steering should be smooth without any jerking. Check out the front end assembly to see if it has been welded on and or repaired, the 4020 front axle is one of its weaker links imo. Look at batteries and their boxes as none of these are cheap. Tires, I think most had 15.5 38 rears or 16.9 38 rears those things can be expensive too. I think a good pull in 5th gear to see how the engine performs power wise is a good idea. The lower gears can hide the lack of power imo. Run it long enough doing the try outs to see what is leaking, some repairs are simple while others are not. Last make a list of the repairs you think are important to make and get an idea of what the parts will cost to do this. Price these parts out at your dealer.

Last thing I would say, don't expect everything to be perfect on a 45 year old tractor.

 

[Textrout]

I'm looking for a 4020 in propane, but it's kind of a rare bird. to your question: Listen/watch for blowby, smoke, or funny noises. A very small amount of hydraulic leaks is probably no big deal, but some have a strong tendency to go thru the fluid. Most everything else has been mentioned above. If you have a good tractor mechanic, the older the better , by him lunch (or pay him something) to have him come with you to look at it. As mentioned above, you have to run the thing for a while to know it's disposition, strengths and flaws. I love these tractors though, and because they are popular, you can get virtually any part for it. Not a bad investment if it's a good tractor.