Use a short 3/8" bolt. Run a nut on it to the end of the threads. Then wedge a 5/16" flat washer into the rubber on your current battery cable after you pop out that silly 5/16" headed 3/8" screw.
Screw the 3/8" bolt through the cables, and into the battery, then use the jamb nut to tighten the cables down.
Martin
Screw the 3/8" bolt through the cables, and into the battery, then use the jamb nut to tighten the cables down.
Martin



