Quote:
Originally Posted by Aufgeblassen
But depending upon how much pressure you apply, the air drops proportionally. So if have no clue how much pressure you apply, results vary tremendously:hellno:!!!
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It must have been awhile since you did a leak check/pump down. The procedure is in any DMV CDL Manual. It does not require an applied brake pressure gauge(Which is not require in an air brake equipped vehicle), but require using the air pressure gauge.
After turning off the engine and releasing brakes, you let the air pressure stabilizes then watch for a minute for any pressure drop. Then apply firm and steady pressure to the brake pedal and watch for a minute any pressure drop. The pressure drop allow for brakes off is 2 psi single, 3 psi for 2 vehicle combination, 5 psi 3 or more vehicle combination. The pressure drop allow for brakes on is 3 psi single, 4 psi for 2 vehicle combination, 6 psi 3 or more vehicle combination.