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2 MH Utility Vehicle Section 2 SECTION 2: OPERATION A. CONTROLS, INSTRUMENTS AND SWITCHES The tractor controls and instruments include a headlight switch, ignition switch, hour meter, ammeter (if equipped), water temperature gauge (if equipped), oil pressure gauge (if equipped), heater switch (if equipped), dome light (if equipped), wiper control switch (if equipped), automotive-type seventeen (17) inch steering wheel, gear shift unit, glow plug button (if equipped), brake pedal, parking brake lever, full-sized accelerator pedal, horn button, and a turn signal light lever mounted on the steering column. The control layout is designed to combine maximum driving comfort with maximum efficiency. The accompanying illustration (see Figure 2-1) shows the location of the controls, while the following gives a brief summary of their operation. It is essential that the operator becomes accustomed to both the location and the operation of the controls, before attempting to drive the MH Utility Vehicle for productive operation. Figure 2-1. Operator's Compartment CAUTION: ALWAYS COME TO A COMPLETE STOP BEFORE SHIFTING FROM FORWARD TO REVERSE OR FROM REVERSE TO FORWARD. 1. Shifter Control Unit The shifter is located on the instrument panel immediately in front of the driver s position. The unit has three positions: Forward, Neutral, and Reverse

3 Section 2 MH Utility Vehicle 2. Park Brake Lever The park brake lever is connected by a cable to the park brake drum attached to the rear of the transmission and is used for parking or holding the tractor on grades and should always be set for parking and released before driving. To engage the park brake, pull the lever toward operator. Push the lever away from operator (down) to release brake. 3. Ignition Switch The ignition switch is an automotive-type switch that has four (4) positions. 4. Accelerator Pedal The pedal is connected to the carburetor (gasoline) or injection pump (diesel) via a cable. 5. Service Brake Pedal Operates the hydraulic braking system. 6. Instruments (e) (f) (g) Hourmeter: Indicates elapsed time of engine operation. Cab Dome Light Switch: Operates the interior cab light (if equipped with cab). Brake Warning Light: Illuminates when the brakes have a hydraulic fluid leaking problem. Ammeter: Indicates the rate of charge or discharge of the alternator to battery circuits. Oil Pressure Gauge: Indicates engine oil pressure. Water Temperature Gauge: Measures the temperature of the engine cooling water system. Headlight Switch: Turns the headlights ON or OFF. Toggle the switch to the up poistion to turn the headlights ON. (h) Wiper Control Switch: Controls the windshield wiper motor (if equipped)

4 MH Utility Vehicle Section 2 (i) (j) Heater Switch: The heater switch controls the heater blower motor (if equipped). Glow Plug Button (Perkins Diesel Only): This button controls the glow plug on the intake manifold and should be held down for approximately 15 seconds prior to ignition. B. PRE-OPERATIONAL CHECKS See also the Periodic Maintenance Schedule in Chapter 2 for maintenance checks that must be performed daily before operating the unit. 1. Fuel System 2. Battery Check all fuel line connections to make sure they are properly connected. Ensure fuel cell drain valve is closed. Check fuel level, and add fuel if needed. Check the battery fluid level. Top off with distilled or approved drinking water, as needed. WARNING: WHEN BATTERY CABLE CONNECTION IS REQUIRED, ALWAYS CONNECT THE POSITIVE CABLE FIRST. Connect the battery cables, if disconnected. 3. Tires: Check condition and air pressure in tires (45 psi) and add air, if needed. 4. Engine: Check engine oil level, add oil if needed. 5. Transmission Check transmission fluid level. Note NOTE: This check is to determine if there is fluid in the transmission. If any fluid shows on the dipstick, do not add transmission fluid until it is checked with the engine running, after the engine has reached normal operating temperature. Check transmission cooling lines for proper connections

5 Section 2 MH Utility Vehicle 6. Rear Axle and Reduction Gear Box: Check oil level in the rear axle and gear reduction box and add oil, if needed. The rear axle and reduction gear box are internally connected. 7. Power Steering Fluid: Check level at reservoir. 8. Check water level in radiator. 9. Brakes Check master cylinder fluid level. If low, check for leaks in brake lines. Check service brake to make sure it is working properly. Check park brake to make sure it is working properly. 10. Check that all controls are in working order. C. OPERATING PROCEDURES 1. Start engine. (e) WARNING: OBSERVE ALL SAFETY PRECAUTIONS DISCUSSED IN THE SAFETY SECTION OF THIS MANUAL. Ensure park brake is set. Ensure shifter is placed in the Neutral position. (Starter motor will not activate unless selector is in Neutral). Move ignition switch to Start. Allow ignition switch to return to On. Switch must be returned to Off before it can be moved to start again. 2. Select drive direction (FWD/REV). Apply service brake by depressing brake pedal. Move shifter lever up (toward instrument panel) to select reverse drive direction

6 MH Utility Vehicle Section 2 Move shifter lever down (toward driver s seat) to select forward drive direction. Neutral is located midway between forward and reverse. 3. Release parking brake. The parking brake is a cable-actuated type attached to the transmission tailshaft. The brakeactuating lever is located to the right of the driver s seat in the driver s compartment. To apply parking brake, lift actuating lever up (pull toward operator). To release parking brake, push actuating lever down (push away from operator). 4. Release service brake and depress accelerator pedal. The accelerator pedal/foot throttle is a conventional automobile or truck accelerator and is connected to the carburetor or ECM through a direct coupled pull cable. WARNING: MATCH DRIVING SPEEDS TO LOADS BEING TOWED AND WEATHER CONDITIONS. SLOW DOWN WHEN TOWING HEAVY LOADS AND WHEN ROAD SURFACE IS WET OR ICY, ESPECIALLY ON GRADES. To increase speed, depress foot throttle. To slow the tractor, slowly release the accelerator and apply the service brake. For an emergency stop, release the accelerator pedal and press hard on the service brake pedal. 5. Maneuver vehicle with steering wheel. The steering system is a hydraulic type powered from a belt-driven hydraulic pump. To turn left, rotate the steering wheel counter-clockwise. To turn right, rotate the steering wheel clockwise. 6. Each time the vehicle is parked, apply the park brake, return the shifter lever to neutral and turn the ignition switch to the "OFF" position

7 Section 2 MH Utility Vehicle D. TOWING INSTRUCTIONS 1. Ensure the trailer load is secure and is within the rated drawbar pull of the MH Utility Vehicle. 2. Ensure the towing coupling is secure. 3. Start as slowly as possible to allow any slack in towing arrangements to be taken up. 4. Travel at speeds consistent with road and load conditions. 5. Slow down and sound the horn when approaching corners and junctions. 6. Take all corners wide, especially when towing two wheel steer trailers. 7. Always be alert. Watch out for pedestrians and never follow too close behind other vehicles. 8. Do not carry unauthorized passengers. 9. Whenever crossing road bridge plates, ensure they are secure and are strong enough to withstand the combined weight of the tractor and driver, or trailer and load. 10. When approaching the destination, reduce speed sufficiently far away to ensure a slow, rolling halt. A sudden halt could cause load displacement. 11. Ensure the trailer s parking brake is applied before disconnecting the trailer coupling. If no parking brake is fitted, securely chock tab road wheels before disconnecting coupling. E. TRAILERS The most common types of trailers used in industry today are the conventional flat deck trailers and the trailers fitted with super-structures. The form of superstructure-varies with the trailer s application. These variations include bedstead ends, detachable canvas sides, detachable chains or four permanent sides (one or more of which are usually hinged for loading purposes). Both common types and all variations can be manufactured with either two or four wheel steering. A two wheel steel trailer is constructed with its two rear wheels fitted to an axle rigidly mounted to the trailer chassis, and its two front wheels mounted on a turntable or pivoting axle. The turntable or pivoting axle is directly connected to a drawbar for towing purposes. When towing a two wheel steer trailer, extra care must be taken to allow for rear end swing when cornering. A coupling device, which is attached to the rear of the trailer, enables additional trailers to be connected, hence creating a trailer train

8 MH Utility Vehicle Section 2 A four wheel steer trailer has both front and rear axles mounted on turntables. These turntables are interconnected by a tie-bar The tie-bar runs diagonally from one side of the front turntable to the opposite side of the rear turntable. If the drawbar, which is attached to the front turntable, moves, then the tie-bar arrangement causes the front and rear wheels to turn in opposite directions. Steering stops are placed to prevent the wheels from turning through a full 90 lock, which can cause a load displacement. F. TRAILER BRAKING SYSTEMS 1. Overrun Brakes Trailers which are consistently used to carry heavy loads are usually fitted with overrun brakes. These brakes can be either cable or hydraulically operated. The overrun brakes automatically slow the trailer down when it tends to overrun. In particular, these brakes are recommended when the Utility Vehicle trailer combination is being operated on gradients. 2. Parking Brakes A variety of parking brakes are fitted to trailers. A majority of these brakes are operated when the drawbar is disconnected from the utility vehicle and lowered to the ground. Some other types of brakes include manually operated hand brake levers. If your trailer is not fitted with a parking brake, remember to securely chock the wheels of the trailer before disconnecting the trailer s drawbar from the hitch or trailer coupling. G. SAFETY 1. Tips Safety is the most important aspect of the operator's responsibility. Observe floor loading limits with the unladen weight of the tractor. Ensure the trailer s load is not wider than the aisles en route. Travel at a speed consistent with the road and load conditions. Sound the horn and slow down for corners. (e) Avoid traveling an soft or bumpy ground when possible. (f) (g) Watch out for pedestrians and do not travel too close behind other vehicles. Avoid sudden stops

9 Section 2 MH Utility Vehicle (h) (i) Do not block fire fighting equipment from use by parking or depositing a trailer in front of the equipment. Report any mechanical or electrical irregularities immediately. (j) (k) (l) 2. Precautions Ensure road bridge plates are secure and strong enough to withstand the weight of the tractor or the combined weight of the trailer and its load. Keep clear of the edge of loading docks. When cornering, watch out for the trailer s rear end swing. REMEMBER: A safety minded driver protects both himself, and others, and eliminates unnecessary damage to the tractor and its load. WARNING: ONLY AUTHORIZED DRIVERS SHOULD BE PERMITTED TO DRIVE. Upon stopping a vehicle, place transmission shift lever in neutral, apply park brake, and turn ignition switch to OFF position. Maximum tow speed of the tractor is 28 mph. Only qualified personnel should service this tractor

Property of American Airlines

Property of American Airlines MA Tow Tractor Section 2 SECTION 2: OPERATION A. CONTROLS, INSTRUMENTS AND SWITCHES The tractor controls and instruments include a headlight switch, ignition switch, hour meter, ammeter (if equipped),