Replaced my lost loose fitting gas cap on my 1952 1/2 ton pickup with the inexpensive gas cap available from our vendors. Immediately noticed large amount of pressure build up in tank when removing cap after driving. Also started noticing a regular booming/banging sound from behind. Checked frame, springs, etc. Nothing help in eliminating the sound. From this forum thread I started thinking about my pressure build-up. Ordered a more expensive Brothers Original Cap for my '52. Solved all problems with pressure build up and booming sound.
Dan
