[Accelo]

Here is the solution to your problem. The bell that the filter rests on has a spring under it. It is held in place by 2 ears that were made by a special tool that cut the bolt and rolled out the material to hold the bell from moving. You can remove these with a long cold chisel and the bell will come off. Under it will be a seal and a washer and the spring. Remove them and in most cases the seal will be ok. The hardest part of this is to have some one cut a new groove in the bolt just where the metal that was folded out stopped. Then you can install the new copper washer, and reassembly everything and use a snap ring to fit the new groove. Do this one time and it will last the rest of your life.
The seal is just a fat "O" ring.

Or just purchase an adapter for a spin on filter.