Reference: CMP seat back coil spring dimensions

[Grant Bowker]

Originally Posted by Bob Carriere

Standard heavy duty key FOB rings work perfectly.

Or make your own........ we have seen on a few trucks that the rings were actually washers of approx. 1/2 inch that had been drilled at four location 90 degrees apart......noon..3..6..9 on the clock.

In the perfect world, we need to be looking at one piece, closed rings (originals look like they were welded) so that they can't open up under load.
Drilling washers is a bit fiddly, but easy. Done it.