Does Seal A Wheel block the valve stem from inside when air pressure is released?
(Some vehicles operate at 50% tyre pressure in desert environments to effect increased traction for rising up gradients. Often tyre pressures are reduced at the bottom of the hill.) This is unlikely. If the valve stem were placed in the correct position during application blockage would not occur since the physical position of the valve will be away from Seal A Wheel reservoir. Most large vehicles use tyres with high walls and this is unlikely to occur with the valve stem in any position.
