I pulled the tank on the El Camino I am working on to clean it. The screen on the sending unit (which apparently acts as a filter) is cracked. Is that a problem? Can this little part be replaced? If so, with what, from where?

I took a look at an old sending unit in the garage that came out of my 80 Elky. It seems like the sock connection is crimped onto the fuel line. I don't think it was ment to be removed or replaced. You should get a new sending unit to prevent any debris from getting sucked out of the tank and fouling up your fuel filter. A new sending unit will probably cost you as much as a new tank would.

If your car is fuel injected the screen can be replaced on the bottom of the pump.

Did you consider installing a new mesh over the existing one. It could be attached to the line with stainless wire to avoid rusting.

Spanner,
I have an '80 and just replaced the screen on the sending unit. Got the part at a local NAPA store. The clerk referred to the part as a "sock."
It snaps on, but it looks like it's crimped.