I have an 03 Navigator same suspension as the 03 Expedition, I replaced the front drivers air bag as it was leaking (on the folds) and hissed when i went over a bump or speed bump, now the new bag remains inflated but still hisses when I go over a bump or or speed bump I hear it on the drivers side. I replaced all o'rings except a very small one that came with the air bag kit about 1/4 inch in diameter I couldn't see one that size on the unit. Any help would be appreciated.