[69 L88 Camaro]

I use alot of those connections here at work, Detroit Diesel. I tap the flat part of the clamp all the way around with a hammer and then retighten the clamp. I usually get excellent results. You may want to try holding a large hammer on one side and tap with a small mechanics size on the other. I am guessing you already have this system built and it is leaking. cadpros's suggestion is the way we always build them. Alot easier to assemble also. Good luck