[bobcowan]

I would pull out the palte, and disassemble it. Polish all the parts. Put it together dry, and try again. Mass produced metal parts often have little burrs and areas of roughness that keeps them from moving properly.

Most wet lubes will attaract dirt and grime. Over time, they'll dry up and turn to varnish. You could use a little dry powder graphite, but it won't stay there long.