My neighbour has the above in brass, calibre .22 and serial number H353004. The gun is a pump up pneumatic but has no pressure and I assume the seals are perished. Could the pump up experts on the forum tell me if seals are still available for this model and if they can be sourced in the UK?
I believe that a "special tool" is needed to remove the valve?
I've seen quite a few older Benjis now and most of them will pump and hold pressure with a new pump cup. Seems there is often nothing wrong with the valve seal but the pump cup shrinks with age and doesn't allow pressure build up. Try replacing that first - it's an easy one. While you have the piston out, clean up the pump tube. You'll find a lot of gunk in there - I've used engine de-greaser and a rag to clean.
As for the valve seal, you will need a valve tool for removal of the locking nut and a puller to get the valve out. It should be the same as the pistol.
"but I'll be needin' that gun, fer squirrels and such."