...WD-40! INTO the Metal Sheath, Housing covering the Cable and INTO the Valve.
Does NOT do any good on the Outside! You have to get it INSIDE, where the Binding is!!
The Valve is probably Stuck from years of corrosion. There are Threads here and at panteraplace.com to deal with the Disassembly, Cleaning and the Rebuilding of the Valve.
...You put a Picture at Your Avitar, by going to You 'Personal Zone' at this forum and 'Edit Your Profile', Go to Your 'Avitar', Then you 'Brouse' and 'Download' a Picture from your Picture files or elsewhere! And Don't forget to LOG-IN! Or use the 'Add Attachment', to Post a picture with your thread.
Try It! And Good-Luck!