i bought a unicolor base and some tubes a while ago, and finally got a chance to use it tonight. i processed some roll film, but ran into a slight problem. the part of the tube called " the piston " that allows you to adjust the tube seems to want to leak. i have read greywolf's article on repairing the gasket seals, but have no idea on fixing the leaky piston.

any ideas?

thanks!

- john