Well, if it's not getting air then you need to look at all the parts that supply the air. 1.) do you have the correct powertube with the screw coming out of the side? 2.) is the air line hooked up to the powertube? 3.) did you loosen the small adjusting screw on the side where the air line connects? 4.) do you hear any leaks?

Also, try putting a drop of oil into the piston area. The little metal pin has a plunger on the back side of it. If that is not lubricated it may have a hard time getting pressure behind it.

One more note, if you are low on air, the RT system may not operate.