It worked good for me to have the rear arm assembly out of the skid before trying to put the wheels and snap rings on. Get two pieces of 1" ID tube 3 to 4 inches long. Put the wave washer, wheel and snap ring on one side, then put one tube on that end, put it straight up and down on a block of wood. Put the wave washer, wheel and snap ring on the other end and use the other piece of tubing and a hammer for a driver to seat the second snap ring. You could probably do it with the rear arm on the skid, with a second set of hands to hold the tube and push against the far side while seating the snap ring.