Komatsu HD785-7 Service Manual

Online PDF Komatsu HD785-7 Service Manual

High Performance Komatsu SAA12V140E-3 Engine 
This engine delivers faster acceleration and higher travel speeds with high horsepower per ton. Advanced technologies, such as High Pressure Common Rail injection system (HPCR), air-to-air aftercooler and efficient turbo-charger enables the engine to be EPA Tier 2 emission certified. High torque at low speed, impressive acceleration, and low fuel consumption ensure maximum productivity.

Mode Selection System with VHPC
The system allows selection of the appropriate engine output mode <Power mode > or <Economy mode>, according to the working condition. The mode is easily selected with the switch in the operator’s cab. When the key switch is turned on, Economy mode is selected automatically. Power mode can be selected by using the switch when needed.

Variable HorsePower Control (VHPC)
Both in Power and Economy modes, the VHPC system detects whether the machine is loaded or unloaded and selects the optimum horsepower setting mode, providing both high production and low fuel consumption.

  1. Power mode: Makes best use of the horsepower to attain optimal production. This mode is suitable for operations including uphill travel loaded where throughput is the top priority.
  2. Economy mode: Sets the maximum horsepower at a lower level to reduce fuel consumption. The machine maintains sufficient power for normal operation in this mode.

These curves are provided to establish the maximum speed and gear position for safer downhill travel with a given distance. Read from gross weight down to a line for total resistance in percentage. From this weight resistance intersection, read horizontally to the curve with the highest obtainable speed range, then down to maximum downhill travel speed the brakes can safely handle without exceeding cooling capacity.

KOMTRAX Plus controller monitors the health conditions of major components and enables remote analysis of the machine condition and its operation. This process is supported by the Komatsu distributors, factory and design team.

F7-R2 (RH/RL) Fully Automatic Transmission
The transmission is configured with 7 forward and 2 reverse gears. Fully automatic control is applied to all forward gears and an optimum gear is automatically selected according to the travel speed and engine speed. The shifting point is automatically selected depending on the acceleration of the machine to reduce excessive fuel consumption.

Two-speed Selective Reverse Gears (RH/RL)
In order to meet various operating conditions, two reverse gears are provided. The switch on the panel allows the operator to usually select the appropriate gear for the application, RH or RL depending on the job site conditions. Furthermore, the reverse gear is equipped with a lockup clutch, just like forward gears, allowing the operator to reverse the machine without concern of overheating.
Suitable for normal operation. Thanks to the lockup clutch, the machine can be reversed at higher speed.
Suitable for operation where steep grades are existing.

Anti-pitching 4-wheel Oil-cooled Multiple Disc Retarder (AP-FOUR)
The machine is equipped with 4-wheel retarder AP-FOUR that applies retarding force on all four wheels. With this retarder, the retarding force is shared between four wheels. This reduces the possibility of tire-lock and enables effective use of retarder capacity, allowing stable downhill travel. The machine descends slopes smoothly and comfortably without machine body pitching since retarding force on front and rear wheels is controlled independently.

Auto Retard Speed Control (ARSC)
ARSC allows the operator to simply set the downhill travel speed and descend grades at a constant speed. This allows the operator to concentrate on steering. The speed can be set at increments of 1 km/h per click (within ±5 km/h) to match the optimum speed for the slope. The retarder cooling oil temperature is constantly monitored and the descent speed is automatically reduced, if necessary.

Reducing Hydraulic Losses & Optimizing Transmission Control 
Hydraulic circuits such as brake cooling, steering, hoist control, etc. are thoroughly reviewed and the transmission control is optimized to reduce the fuel consumption. As a result, the fuel consumption at medium and light load operations are improved.

Automatic Idling Setting System (AISS)
This system facilitates quick engine warm-up and operator cab cooling/warming. When setting the system ON, engine idle speed is kept at 945 rpm(min-1), but is lowered to 750 rpm(min-1) when the coolant temperature rises to 50°C. Speed automatically returns to 945 rpm(min-1) when the coolant temperature drops to 30°C.

Small Turning Radius
The MacPherson strut type front suspension has a special A-frame between each wheel and the main frame. The wider spaces created between the front wheels and the main frame increase the steering angle of the wheels. The larger this steering angle, the smaller the turning radius of the truck.

Long Wheelbase and Wide Tread
With an extra-long wheelbase, a wide tread and an exceptionally low center of gravity, the HD785-7 hauls the load at higher speed for greater productivity, and delivers superior driving comfort over rough terrain.

Spacious Cab with Excellent Visibility
Wide glass areas on front, side and back, plus plenty of space in the richly upholstered interior, provide a quiet, comfortable environment which enables to see and control every aspect of operation. Front underview mirrors also contributes to improve visibility.

Ergonomically Designed Cab
The ergonomically designed operator's compartment makes it very easy and comfortable for the operator to use all the controls. The result is more confident operation and greater productivity.

Easy-to-see Instrument Panel
The instrument panel makes it easy to monitor important machine conditions. In addition, a caution lamp warns the operator of any malfunctions that may occur. Malfunctions are recorded in the monitor and service codes, appear on the instrument panel. This makes the machine user friendly and easy to service.

Ideal Driving Position Settings
The 5-way adjustable operator seat and the tilt-telescopic steering column provide an optimum driving posture, for increased driving comfort and more control over machine operation. The suspension seat dampens vibrations transmitted from the machine and reduces operator fatigue as well as holding the operator securely to assure confident operation. 78mm width seat belt is provided as standard equipment.

Synchronous Control of Engine and Transmission
At the time of gear shifting, the engine speed is controlled to coincide with transmission rotation speed to reduce shifting shocks. The synchronous control also contributes to improve durability of power train since it reduces torque fluctuation.

Advanced K-ATOMiCS
The electronically controlled all clutch modulation system “K-ATOMiCS” that optimizes the clutch engagement oil pressure at every gear is further improved so that the oil pressure at lockup clutch engagement is optimized to realize smooth shifting without torque off. “Skip-shift” function Automatically selects the gear according to the slope grade when driving uphill without shifting down to the lower gear one by one. It reduces the num ber of downshifts, makes the driving smoother, improves the operator’s comfort and reduces spilling of material.

The MacPherson Strut Type Front Suspension 
The MacPherson type independent suspensions are installed to the front wheels. The linkage arrangement with less friction allows the front wheel to follow the undulation of road surface smoothly, 
realizing excellent riding comfort.

Three-mode Automatic Hydropneumatic Suspension (Option)
Suspension mode is automatically switched to one of three stages (soft, medium and hard) according to load and operating conditions, for a more comfortable and stable ride.

Viscous Cab Mounts
Large capacity viscous cab mounts with excellent damping performance are used to mount the cab. They reduce cab vibration significantly and provide comfortable cab space with superb quiet ness and less vibrations. Noise level at operator’s ear 75 dB(A)

Electronic Hoist Control System
The control lever is short in travel and can be operated with a light effort. “Kick-out function” provided for the lever facilitates the hoist operation, eliminating a need to hold the lever in “raise” position. Furthermore, body seating shock is significantly reduced because a sensor detects the body just before seating on the frame and reduces the lowering speed.

Wet Multiple-disc Brakes and Fully Hydraulic Controlled Braking Systems 
Realize lower maintenance costs and higher reliability. Wet disc brakes are fully sealed to keep contaminants out, reducing wear and maintenance. The brakes require no adjustments for reducing wear, meaning even lower maintenance. The parking brake is also an adjustment-free, wet multiple-disc system for high reliability and long life. Added reliability is designed into the braking system by the use of three independent hydraulic circuits providing hydraulic backup should one of the circuits fail. Fully hydraulic braking systems eliminate the air system so air bleeding is not required, and water condensation that can lead to contamination, corrosion and freezing is eliminated.
Extended Oil Change Intervals
In order to minimize operating costs, oil change intervals are extended: 

  1. Engine oil : 500 hours
  2. Hydraulic oil : 4000 hours

Payload Meter (PLM) (Option)
PLM allows the production volume and the working conditions of the dump truck to be analyzed and controlled directly via a personal computer. The loadage is also indicated with the outside lamps. The system can store data of 2900 max. working cycles.

Advanced Monitoring System
The Komatsu advanced monitoring system identifies maintenance items, indicates oil and filter replacement times left and displays abnormality codes. This monitor system helps to reduce diagnostic times and maximize machine production time.

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