you can actually suck on it and feel the little plunger move in the back...

someone makes an adapter that you can screw the power valve into and check it will a vacuum pump...

or you can just replace it...


Tony

70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)