Thanks, MrToad. The shiny plunger is returning fully into the bushing[threaded with nut],with no shiny left exposed and the L shaped[sprung] lever is returning fully to its stop. I tapped the plunger gently to make a fully home position. The return springs of pedal and L shaped lever appear in good working order.However there does not appear to be any free play on the plunger in its fully in or out position when pedal is pressed to floor. Is any needed? The little sump and drain plug are directly beneath this assembly.

Bruce, May 2009

Hello
It would be normal to allow a small amount of free play in the linkage, ie. a small amount of movement in the pedal before the plunger moves.
Unfortunately, you now seem to have checked and ruled out the easy options. I am sorry, but it is looking as though you have a g/box problem, which is something I can't advise on - have never had cause to go inside one.
You might try giving Lee Gregory a call. Search for "Digger Doctor" for phone no./email. He will probably advise and can supply s/hand parts for these older m/c's if necessary.
Sorry I can't help futher!

Apologetic Mr. Toad, May 2009