Here by PM request are some photos of the rubber bumpers I made from the solid inner rubber tire from a skid steer. The rubber is dense, but not as dense as regular tire rubber. A band saw was used to make the cuts and followed up as needed with a razor knife to clean up edges for fitting. I suggest wearing a dust mask when cutting the stuff and wearing gloves. It smells foul and leaves a nasty, hard to scrub odor on hands otherwise.
New rubber bumper
Rough cut rubber bumper replacement
Template for rubber bumper replacement
Old rubber bumpers used for template
Rubber bumpers installed on brackets fore and aft above spring overloads