Mine was locked up for over 20 yrs. because I pumped too much air in it and didn't know it. The hammer couldn't hit the piston hard enough. Couldn't figured it out. Finally whacked the piston in the valve assembly with a hammer. This took a couple try's. This released the air. Works fine now. The air valve is steel to steel sealed. There are no leather or rubber seals. That's how well machined the assembly is. Really, it held air for over 20yrs.. I thought that rust had sealed it. Not so, just too much air. Lesson - Do not pump it up more than the recommended number of times of which I think is 10 or 12. Can lock up after 20 + pumps. This may help.
