1988 gas tank pressure test

Clean out the tank. Place one of those nitrile or latex rubber gloves over the filler neck coming out of the tank. Stick the glove inside the tank and stretch the opening for the hand insert around the outside and place rubber bands around the glove to hold it in place. Seal off other openings to the tank with small diameter hose and squeeze shut with vice grips. Leave one opening open and insert rubber tube. Attach other end to hand pump and pressurize the tank until the glove pops out the filler neck and inflates like a balloon. This should put about 4 lbs of pressure inside the tank. Begin at night and note temperature at location and keep in place overnight. Come back in morning before it heats up and note the size of the balloon glove. It is smaller, you have a leak. Important to note the temp because if the area heats up, the balloon will expand. Make sure the tank is cleaned out well and no gas vapors present.