Hi guys, having problems with my truck. (sig. truck) I replaced the injectors and one of the return caps will not stop leaking. I had reused the old caps and orings ..I know,bad idea, then I replaced the caps and orings with new ones but one cap still leaks. It drips fuel when running and makes the truck hard to start cold.The sealing surfaces on the injector are in good shape. Is there something I could use to seal the cap and injector?