I have had a small but annoying rms leak for a while now, even after swapping out a couple new seals to no avail, I never considered the possibility the main might be damaged.
I bought a rms sleeve that I test fit with a seal. It's a nice fit. $5 so couldn't pass it up.
It's fed mogul/national 99331.
(About 3.31" diameter.)
I haven't actually installed on car yet but looks like it'll work.

 

I actually had no idea these existed. That's pretty cool.

 

I used a similar sleeve to fix a worn front crankshaft
on an American car years ago.