I have bought two gasket sets for my 36. Neither set had a seal for the main shaft on the sprocket side. Looks like a felt, or cork of some kind went into the recess. I took a couple measurements and went to my local bearing house and found a lip seal that went right into that recess. It was a SKF 9826. I got a 1/4 in thick one, but would get a thinner one next time. Should work. Stan