OM3020.3 02/01 Operation - Section 3 Instrument Panel & Indicator Lights Page 3-29 (12, Figure 3-6) WHEEL BRAKE LOCK CONTROL The Wheel Brake Lock should be used with engine running for dumping and loading operations only. The brake lock switch actuates the hydraulic brake system which locks the rear wheel service brakes only . When pulling into shovel or dump area, stop the truck using the foot-operated service brake pedal. When truck is completely stopped and in loading position, apply the brake lock by pressing the rocker switch toward the “On” symbol. To release, press the rocker switch toward the “Off”symbol. Use at shovel and dump only to hold truck truck in position.
Do not use this switch to stop truck, unless foot-operated treadle valve is inoperative. Use of this switch applies rear service brakes at full, unmodulated pressure! Do not use brake lock for parking. With engine stopped, hydraulic pressure will bleed down, allowing brakes to release! (13, Figure 3-6) PARKING BRAKE CONTROL The Parking Brake is spring applied and hydraulically released. It is designed to hold a stationary truck when the engine is shutdown and keyswitch is turned “Off”. The truck must be completely stopped before applying the parking brake, or damage may occur to parking brake. To apply the parking brake, press the rocker switch toward the “On” symbol.
To release the parking brake, press the rocker switch toward the “Off”symbol. When the keyswitch is “On” and Parking Brake switch is applied, the Parking Brake indicator light (A3, Overhead Panel) will be illuminated. NOTE: Do not use the parking brake at shovel or dump. With keyswitch “on” and engine running, sudden shock caused by loading or dumping could cause the system’s motion sensor to RELEASE the park brake . (14, Figure 3-6) TACHOMETER The tachometer registers engine crankshaft speed in hundreds of revolutions per minute (RPM). Governed RPM (DDC/MTU 4000 Series Engine): Low Idle - 700 RPM Full Load - 1900 RPM High Idle - 1920 RPM