(1) Motor logging trucks and trailers must be equipped with brakes or other control methods that will safely stop and hold the maximum load on the maximum grade.

(2) All trucks with air brakes must be equipped with a readily visual or audible low air pressure warning device in good working order.

(3) An air loss rate out-of-service condition exists if an air leak is discovered and the reservoir pressure is not maintained when:

(a) The governor is cut in;

(b) Reservoir pressure is between 80 and 90 psi;

(c) Engine is at idle; and

(d) Service brakes are fully applied.