Cab air release issue

[Dayco]

When I drop the cab airbags everything is fine but when I reapply air to the bags to raise cab back up it constantly vents through the vent on the control box when I drop the bags it stops i have takin the valve out and looks ok .... not sure where to go from here

 

[Suprman]

Some of the air bag control knobs have a small check valve behind it. Some just have o rings. Unscrew the control.

 

[Dayco]

So I can’t get brass valves apart and the silver button is leaking air as well .... anyone have this for sale