https://www.truck-manuals.net/mack/ 62 INSTRUMENTS AND CONTROLS
CAUTION The maximum safe oil temperature for MACK transmissions is 121°C (250°F) for mineral-based oil, or 148°C (300°F) for synthetic oil. Continued operation with oil above this temperature will cause rapid deterioration of the oil’s lubricating properties and is NOT recommended. Consult the vendor manual for non-MACK components. 20. Air Pressure Gauge — Indicates the air pressure in the air brake system(s). The normal operating air pressure is between 759 kPa (110 psi) and 897 kPa (130 psi) in both air brake systems. If pressure drops below 75 psi (±5 psi) in either system, the warning buzzer and warning light will go on. Determine the cause of failure before proceeding. Primary air pressure is supplied to the rear brakes and is indicated by the green pointer on the gauge. Secondary air pressure is supplied to the steering axle brakes and indicated by the orange pointer. 21. Park Brake Valve — Yellow diamond-shaped knob. Pull to apply. Push to release. Applies the parking brakes. Note: The parking brake DRL allows the daytime running lights to be off while the concrete pumper is in operation. 22. Ignition Switch — Refer to STARTING THE VEHICLE in the OPERATION section for specific starting procedures. Insert the key into the switch. Turn the key clockwise to the ON position. To crank the engine, turn the key clockwise or push the optional starter button. To shut down the engine, turn the key to the left. 23. Windshield Wiper/Washer Controls — Depress the ON/OFF button to turn the windshield wipers on or off. Pull the button up to make the wipers faster, push the button down to make the wipers slower. Depress the "WASH" button to activate the washer fluid.
C0029692
