Seriously, re-sealing the thread joints with Teflon should take only a few minutes. The only thing the gasoline might have done is broken the seal between he plastic tube in the 90, depending on the sealant used. Just pull it out, clean it up with xylene and allow to dry for several days. Then glue it back in with RTV Silicone, which will resist diesel just fine. Most epoxies, including West Systems, are gasoline-proof. Nothing to it. They probably used something that was not gasoline resistant, which is rather dumb. Better to figure out what the gasoline damaged and fix that, so that next time a mistake happens there is no problem.
I doubt this is off the shelf, and it's good to know your equipment. This is the sort of thing it is good to be able to fix underway.