If you are referring to the Air Cushion / Bump Stop. That always leaks air. The CHNC is an air hog. And if you are running one with just a slight compressor system. The compressor will work hard to keep up. It is one of the negatives of this machine.
Post a photo of what you are talking about and perhaps I can help you more.
I remember way back when......
We ran two 1995 CHNC3's with one 5HP 60 Gallon Compressor. You could go into the compressor room and grill steaks on the compressor's cylinder heads.
With just a touch of motor oil Ajou sauce.