Komatsu PC78UU-6, PC78US-6 Excavator Service Manual

Table of Contents

01 GENERAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01-1
10 STRUCTURE, FUNCTION AND MAINTENANCE STANDARD . . . . 10-1
20 TESTING AND ADJUSTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1
30 DISASSEMBLY AND ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1
50 OTHER SPECIFICATIONS (PC78US-6 For Norway) . . . . . . . . . . . . 50-1
90 OTHERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90-1

GENERAL
This section lists the general machine dimensions, performance specifications, component weights, and fuel, coolant and lubricant specification charts.

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
This section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting.

TESTING, ADJUSTING AND TROUBLESHOOTING
This section explains checks to be made before and after performing repairs, as well as adjustments to be made at completion of the checks and repairs. Troubleshooting charts correlating Problems to Causes are also mention in this section.

DISASSEMBLY AND ASSEMBLY KOMATSU Excavator

This section explains the order to be followed when removing, installing, disassembling or assembling each component, as well as precautions to be taken for these operations.

Automatic change of travel speed
1) Automatic selection corresponding to engine speed
• If engine speed drops to 1,350 rpm or less when travel speed selector switch is in HIGH and travel speed is HIGH, travel speed changes to LOW automatically.
• If engine speed becomes 1,550 rpm or less when travel speed selector switch is in HIGH and travel speed is LOW, travel speed changes to HIGH automatically.
a If travel speed selector switch is in LOW, travel speed is not changed automatically.