My neighbor gave me an old Benjamin ,Benjamin Franklin 22 cal. air gun. Its in pretty good shape,walnut stock,but no rear sights. Problem with it is it does not hold air. He had some air gun valve oil that he tried to get it to work but to no avail. I assume the piston it dried out. Any suggestions? Thank you

You can order a valve replacement kit and maybe a sight from Pyramid air or have it rebuilt by Mac1 or others.
They're good guns and aren't hard to swap valves on.
The guys will be along shortly to direct you a bit more, Good Luck!

Mine was locked up for over 20 yrs. because I pumped too much air in it and didn't know it. The hammer couldn't hit the piston hard enough. Couldn't figured it out. Finally whacked the piston in the valve assembly with a hammer. This took a couple try's. This released the air. Works fine now. The air valve is steel to steel sealed. There are no leather or rubber seals. That's how well machined the assembly is. Really, it held air for over 20yrs.. I thought that rust had sealed it. Not so, just too much air. Lesson - Do not pump it up more than the recommended number of times of which I think is 10 or 12. Can lock up after 20 + pumps. This may help.

6 pumps max. My own still shoots after near 60 years.

Mine leaked. I sent it off to get fixed, and it works great again. My boys kill all sorts is critters with it. As stated, don't over pump it, and leave 1 pump full of air in it when done shooting. 6 pump is max in mine, got it in the late 70s.

Have one that I got for Christmas when I was 12 - 40 years ago now. Still works like a champ.

I was able to put in new seals from Pyramid, so you probably can too.

Still have mine from 1955 or 56. A number of years ago the factory in Racine for Sheridan offered a rebuild for about $28, so my son and a bunch of his buddies sent all our Benjamin's and Sheridans in. Rebuilt, rebounded and with a new owners manual was what we got back. I chrono's mine and figures were within 5-10 fps of the factory specs. 6 pumps was 635 and eight got 695. I keep 2 pumps in it when stored. Got a Blue Streak I'm thinking about a MacOne steroid treatment for.

Mine after a third reseal and a NOS pump handle from a couple of years ago. Bought new in 1968. A lot of dead critters...