I purchased some flexible valve extensions.
My clamp-on air chuck would not seal.
It turns out the inside diameter of the extension opening was SLIGHTLY smaller than all of my other valve stems.
I unscrewed the front part of the check and filed down the center section (which depresses the valve core). It was a touch too wide.
Now this check works on all my valves.
2014 40QBH Phaeton DP Cummins 380HP ISL, Freightliner XC, 2014 Jeep Trailhawk TOAD
Blue Ox Aventa tow bar, SMI Air Force One -South Orange County Ca.