RE: Top-Flite T-34
Take a good look at your retract mechanism. There is an up and a down lock position. The air piston moves the retract locking "pin" from one extreem to the other. At the extreems the retract locks. You can move that "pin" with a small screw driver if there is no air in the system. Once it's moved off the lock the gear leg can be moved up or down by hand.