Hi Again Lefty
Once you mentioned about the ends of the shave plate bolts being ground off, I realized that the machine was probably never set up correctly from new. Whether the machine is sold from a box store or local hardware store, the skid shoes are never properly set, unless the set-up person at the hardware store actually knows what he or she is doing.
Every year I see snow blowers come in with worn scraper edges, worn off bolts and cooked transmissions with the skid shoes having never touched the ground. I believe setting the scraper bar height on these machines is covered in the owner's manual, but who reads these anyway? If the machine has been riding on the scraper edge instead of the skid shoes, this may tend to push the bottom edge of the collector housing up. Just my thoughts,
Sky