Question 9 of 20
Score: 0/0When testing the trailer brakes with the hand valve on by opening the service line valve at the rear, what should you hear?
ExplanationOpening the service line valve with the hand valve on should cause air to escape, producing a hissing sound that indicates the brakes are being applied properly.
Missing these? The CDL Study Bundle turns the rules you keep getting wrong into one quick reference.
Next Question →
Did you know? More trailers means more couplings to inspect; don't skip the air-line checks.
← Back to Doubles & Triples tests