Tuning H9 Leaking Air

Try generously lubing the pump first preferably with Alphabet org auto trans stop leak quick fix or regular Alphabet org extend the pump handle all the way lube the pump piston seal and work it in repeat several times. If you are lucky it will hold after a day or so of working it in. Shouldn't be that old probably a 91-93 unless it's a newer H9A that followed.

Otherwise...Contact .. For parts and or service...

https://www.jgairguns.biz/

https://www.bakerairguns.com/repair-restoration/

http://www.mac1airgunshop.com/mobile/