Justa lil' update.
Mostly an FYI for Al and gggGary.
I have my QuiteRide pump and release valve mounted on the back of my helmet.
Out of the way, out of the wind, easy to access.
Earlier this year, the release valve would get harder to press, and wouldn't hold pressure. Replaced it with a 2nd spare unit. Then, last month, the same thing, hard to press and leaking.
Took the 1st unit apart, simply pull the brass plunger out. There's a tiny egg-shaped ball on the stem. Apparently these things are assembled by simply pressing the ball-end thru the hole at the top of the valve body. The plastic hole is small enuff to capture the ball, creating the seal.
Coupla problems here. The spring is a bit too stiff, and its sharp end digs into the plastic seal, distorting the hole. Should be using a weaker spring, with flush ground ends.
And, the backside of the egg-shaped ball is rough, and has too shallow of an angle. The strong spring pulls it out too hard, eventually causing it to wedge tightly in the hole. A manufacturing quality issue. Should be ball-shaped and smooth.
So, I bored-out the plastic valve body, made a better valve from brass, and press/glued it into the body.
Works great.
Here's the parts used to fix the 2nd valve.
It's a little longer, to hold a plug.
Removing the plug grants access to disassemble the valve for cleaning, if need be...