seaboyforever:
Most folks pick up on how they get removed and repaired the first few times they take their tanks in for VIP, maybe it strikes some as ironic that you have spent your Navy and life time diving and don't know how to remove a K-valve, never seen a VIP done.
Pressure determines the neck size, find a suitable K-valve for cheap and you can unscrew one and screw on the other. (This is the non-O2 clean method)
You don't have to go to your LDS but they can fix the valve you have, most likely cheaper than you can replace it.
Ron Brandt:
Pshaw, you can do it with a regular old screwdriver if you don't mind cutting a notch in it.
