I am finally preparing to fly my new to me 76 Super Cub. I taxied over to fuel it and noticed that caps are extremely difficult to get off and darn near impossible to get on. The gaskets are approx 1 3/8 ID and 2 1/4 OD with a thickness of 1/8 inch. When looking up gaskets I am finding some are 1/16 thick which sure seams like it would be better. It feels as if I am going to break the tabs off the top getting these back on. Can someone point me to the correct part number? These cannot be correct!