Locate the pump's handle pin, which is a metal cylinder that allows the handle to pivot. Unclip the metal wire that holds the handle pin in place.
Slide the handle pin out. Use pliers if you can't get a good grip on the pin. Tap the pin gently with a hammer if it is rusted in place.
Clean off any rust on the pin with fine-grit sandpaper. Reinsert the pin and see if the handle pumps freely.
Locate the handle fulcrum, which is the hinged mechanism at the end of the handle where it connects to the piston.
Slide the appropriately sized socket over the nut that holds the fulcrum together. Turn the nut clockwise with a socket driver to tighten it. Test the handle for functionality.
Consult the owner's manual for additional troubleshooting options or to determine the location of handle components.