Replacing old DE filter valve

Hello - I have an old Purex SMBW 2000 filter. When I had an air leak in the system, I found that the filter was leaking water into the drain (I was able to stop the leak temorarily by closing a valve on the drain plumbing). So I am trying to replace the valve assy at the bottom of the filter. I used a puller to get the old brass valve rotor out of the valve body and have already bought a new one, which is made out of some kind of very hard plastic. However, the old valve body that the rotor goes into has rubber seals in the openings to the drain and outflow ports, while my new rotor has a seal grid attached to it instead (which I'm sure works much better). The old rubber seals I think are my problem - they are worn and torn, kinda stick out, and made turning the backwash valve before very hard to do. My question is - should I just cut out the old rubber seals, and install the new rotor?

I sure don't want to have to buy a new valve body - it's over $300 - in that case, I may as well just take everything back and buy a new filter.

Maybe someone has run into this before or knows the answer.

Thanks very much.