Brake Shoes Will Not Fit In Drum
These brake shoes were manufactured with the expectation that your brake drum will have 40 years worth of wear and possible even been turned down at some point to smooth things back up. Because of this, the shoes have been made slightly taller than the originals (it is easier to grind down a little material if you don't need it than it is to add material if you do).
In most installations (around 90%) they fit just fine out of the box. If your tractor has new drums or an unusual lack of wear then the shoes may fit too tight in the drum and may need to me modified. This is easily accomplished with a hand grinder or dremel tool by grinding a very small amount of metal off of the bottom of the feet of the shoes (see picture below). It does not take much!
Test fit the shoes in the drum after removing a little material by mounting the shoes to the brake plate. The shoes should just barely drag as you slide them in the drum.