Original post by: blackwood ,
'''Check the bottom of your foot valve there is a rubber dust cover that can mask the sound of seeping air. Put your hand over the bottom and see if there is any pressure build up. Same thing with the brake valves inside the frame rail. As far as checking for leaking air lines I advise you to buy one of those sprayers that holds 3-5 gal and make up a solution of dish washing liquid and water and completely saturate all your air lines good. Also spray your brake valves in the dash out side and behind the dash panel too.'''''italic text''