concave in a 72 All Crop Harvester

I bought a concave from Tom Yaz a few years ago and now my AC 72 All Crop needs it. There is not a lot of information on the allcropharvester.com site about how to do the job. Figuring out what to take apart and how to do it looks like the worst part. Has anyone done it ? Any advice ?
Thanks
Greg

I got that same combine , I havent done that job , I think its an excellent post . Im hoping for reply also.

I replaced the concave in a 66 last summer. Quite a task. I removed the feeder apron and all the cylinder bars. The rivets that hold the concave in are the hardest to remove. Took about a week to complete.

It looks like you are the only guy who has done it.

Apparently there is enough room to get the new concave in once the cylinder bars are out of the way. Why did you decided to remove the remains of the old concave rather than lay the new one over the top ? If you did it again, would you do it the same way ?

Thanks
Greg

I helped my uncle do that many years ago.
All I remember is that it was a hot job that day.
I rebuilt the cylinder and put concave in an my AC 40 a few years ago.

I left the very back of the old concave in place. the rest was full of holes and I didn't think the new one would lay flat. A lot of tin and duct tape had to be removed too.

(quoted from post at 16:47:50 07/18/21) I bought a concave from Tom Yaz a few years ago and now my AC 72 All Crop needs it. There is not a lot of information on the allcropharvester.com site about how to do the job. Figuring out what to take apart and how to do it looks like the worst part. Has anyone done it ? Any advice ?
Thanks
Greg

Click to expand...

My 72 was in bad shape, took the header off and pulled the cylinder. They needed work anyway.
You can move the separator as you drill or grind out the rivets.
I had a local welder tack the new concave in.
It is a lot of work. Replace everything that needs it while you are in there.

It is a big job to change the concave, 4-5 days. We did it as an overlay rather than remove the old concave.

Useful things to know:
Put the header on a pallet and block up the cross tube behind the header so it doesn't want to tip over when you pull the head away from the machine.
Chain /tie strap the head to your skid steer or fork lift to keep it from rocking back. Use a jack to support it when it is on the ground.
Trim 1/8 inch off the sides of the new concave and round the front corners so they don't dig in.
Remove all but one or two of the cylinder bars.
Slide the new concave over the top and around the back of the part of the cylinder without the bars.
Use a bar or good 2X4 under the cylinder shaft to press the back edge tight against the old concave and attach it with a dozen Tek screws.
The new concave is not bent to the same radius as the original. You will have to push it down to get the front edge to line up.
Rip a 2X4 down to 2 1/8 (+/-) and position it behind one of the remaining cylinder bars. Turn the cylinder with a 5/8 cold rolled rod and push the new concave down to the bottom of the old concave. Drill the holes for the shelling plate and use it to hold the front edge of the concave.
Weld the back edge to the old concave. Weld through the Tek screw holes where you can't reach the edge of the new concave.
Drill the holes for the threshing bars in the cylinder from underneath. Use the holes in the old concave as a guide.
Use a piece of 1X under a cylinder bar to hold the carriage bolts in place while you replace the nuts.
Get the header close and use a bar to push it home.