Hi Ron,
I too, had a problem with my back blade "digging in". Had a local welding shop in Petoskey plasma cut a slot in a 2" pipe, weld flat washer on each end, and also weld a couple short lengths of chain near each end. I slip the pipe on the bottom of the blade and use a tarp strap across the frame to the two chains to hold it in position. Works like a champ.