Sorry to leave you hangin...
So with truck in the air, on stands, what ever, will the brakes engage without vac? As in will they stop if you spin the wheels?
With foot on the brake, if you start the engine and engage the transmission, vac off, will it hold the rear tires still?
If they don't stop the rears, turn OFF the motor to let the wheel come to a stop.
Thanks for follow up, it really is weird.
VZ what kind of MC are you talking about? PLS...