What to look for in a used combine

I am thinking about looking for a combine. I farm about 100 acres of corn and soybeans. I have never owned one before but I have operated a few in the past. John Deere is king around here so I am thinking I would like a 6620,7720,8820. What should I look closely at on these models ?

My first would obviously be the hours. Then look for
rolled or cracked auger flighting and start wiggling
every bearing you can get to. Also check around for
holes. Grain tank, tailings auger, clean grain
elevator etc. much of it will just be common sense
considering no more hours than you will put on it in
a year. I would really look hard for something that
has been kept inside but that's easier said than
done. Good luck

I would agree with the comments made by newhollandnut. The machines you are looking at range from 28 to 37 years old. You might find some help in a friend or neighbor who has owned and run these machines, too. They tend to have the experience to draw from. Look for thin or worn places in the sheet metal. I have even seen sheet metal worn to the point where it is missing. The places I have seen this are in auger troughs and elevators, and I saw one Titan combine where there was missing sheet metal on the top side of the threshing cylinder, under the seat by the primary countershaft. If I remember, there are a few curtains inside these machines. One behind the beater and one behind the back of the straw walkers above the chopper. If these are missing, the cobs flying around are hard on the inside of the sheet metal. Look for worn or missing pieces in the top side of the straw walkers. I feel this is indicative of a machine that has seen a lot of hard use. Wear in the drive shafts couplers between the transmission and the final drives would also indicate a lot of hours on the machine. You can detect slop in these when moving from forward to reverse with the hydrostatic control lever. The floor of the feeder house can also develop some thin spots. I have seen some machines that had little care, maintenance, or half-assed repairs done and were "junk" at 4000 hours, while others in which the owner spent the money as needed before each harvest season in order to keep the machine in top notch running order. We had a 7700 with nearly 5000 hours and it went through the shop every other year. Whatever it needed was tended to. In the 3600 hours over many years we had it, rarely was there a breakdown, especially those causing more than a few hours of downtime. I also think of a neighbor who had a 1460 IH combine. Every year he got it ready for harvest, but never spent much in preparation for harvest. It continually had issues during the fall because of no preventative repairs or maintenance. That machine was pretty much worn out and a piece of junk with 4000 hours. It was in need of a lot of parts from lack of attention. And they wondered why they had breakdowns during the fall, too. As the old saying goes...................an ounce of prevention is worth a pound of cure. There were a few times there were some hefty repair bills, but again, rarely did we have a significant breakdown during the fall use.

Where you at? 2 Deere's near me I think 6620s. Propbly could be had cheap
Loren

Central Ohio

Look at the 'internals,Cylinder/raspbars,concave,belts,bearings augers,hours, tin.(high hours can mean thin tin/holes in pans)
just make sure its not totally worn out. You can tell.

I would stay away from the 8820 as the parts are not as easily available as the other two and its big machine that needs needs to be kept full to thresh properly. I currently have a 7720 that still get some use and does a great job but cab is not a nice as the 9510. Be sure to drive it to check out the hydro and fell the cross augers to see if they are sharp,that a good indicator if its wore out.