Pump Check Valve Fix:
I fixed the stuck check valve on my lantern. It would pump but not hold pressure. The air would come out the pump knob before it could be screwed shut. I originally tryed to unscrew the check valve, I quickly saw disaster happening and stopped. That valve is TIGHT and soft brass. My next thought was to do no harm. I sprayed carburetor cleaner into the valve to dissolve any varnish. Then, I used a very small punch/probe and some penetrating oil to tickle the check ball. I pumped the tank and pulled the piston out quickly hoping the escaping air would push the ball closed. I did this several times.
Well, it's not perfect but the check valve holds pressure enough that I can get the pump sealed in plenty of time. I'm hoping that over time the check valve will get even better.
Tt