That was the first thing that I did. There is a box on the back of the machine underneath the air cylinder. The air cylinder feeds air to this box and when you use the lever to close or open the jaws, the lever lifts or pushes down a rod in that box that either let's air in, or releases it. I took that apart to find plastic bushings and O-rings in there that were in pieces. It is an old machine maybe it could not stand full air pressure after the leaks were fixed I don't know. I could make new parts and get new O-rings for that rod, but I can't find a repair manual that will show me what those dimensions are for those parts. I need to know what they were supposed to look like in order to make new ones.