Blitz fuel tank switch sucks air

[zemsi]

Both fuel tanks on my F15 are connected and supply fuel to the engine. However, the left hand fuel tank wasn't getting any fuel to the engine lately. So finally, I figured out by bypassing the fuel tank switch that this switch sucks air. I opened it and there were a lot of scratches which must allow the air to be sucked in. She runs very nice on the right hand tank.

So I was wondering, how you solved that problem? And please don't tell my I should only drive on the right tank Are there any modern replacement parts or NOS fuel tank switches around?

Thanks a lot for your input.

Greetings
Chris