Benjamin Repair 342, worth it

Have a 342 picked some years ago and decided to look into repairing. Not holding air so likely would do a seal repair/replace. Question is the pump arm currently doesn’t stay closed. In other words it doesn’t rest inline with the stock. Will this resolve itself when the seals are replaced of is there another issue causing this?
Its a good idea to degrease and flush the valve first. I've used alcohol and cleaner degreaser. People squirt oil in them which holds dirt and debris defeating the valve seal, especially if left uncharged.

Determin what is leaking. There are three leak points.
The plunger (hiss while closing the pump arm). The check valve, (hiss from the pump area with the arm open)
The release valve, or valve washers (hiss from the breach)
A lot of guns only need the plunger replaced, and a flush can bring the valves back to life. Once it's working leave it with a charge when put away to keep the valves sealed.
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