Komatsu D20-5, D21A-5, D21P-5, D21PL-5 Dozer Service Manual

Table of Contents

GENERAL
STRUCTURE AND FUNCTION
TESTING AND ADJUSTING
DISASSEMBLY AND ASSEMBLY
MAINTENANCE STANDARD

1. General Instructions
This section presents under one heading the basic information and procedures common to the sections on “Disassembly and Assembly”, “Testing and Adjustments”, “Troubleshooting”, and “Removal and Installation”. It is essential for the serviceman to thoroughly understand and know this section till it becomes a part of his common sense.

2. Structure and Function.
This section gives a detailed explanation of the “Structure” with details and drawings of the “Constituent Parts” and “block” or “circuit” diagrams, arranged for the serviceman, but also useful as a textbook for training service personnel. The Training Aids should is use to cover the basic theory in this Manual.

3. Testing and Adjustments.
Procedures of all the necessary “Tests” and “Adjustments” are describe with photographs showing the necessary measuring equipment and the location for making the measurements. This should aid the serviceman in his trouble shooting, checking and adjusting work.

4. Troubleshooting
Typical common troubles are listed and systematically described; with their causes and the procedures for finding and diagnosing the symptoms.
As it is impossible to list all of the possible troubles, the serviceman should study the sections covering the “Structure and Function” and “Testing and Adjustments” and apply this knowledge to diagnose any non-listed troubles.

5. Manual Specifications
In this section, all standard dimensions and tolerances that are necessary to perform Testing and Adjustments is mention with drawings together with, appropriate procedures for disassembly and assembly, performing repairs, or troubleshooting. However, basic dimensions and tolerances, for repairs or rebuilding, are limited to those machine parts most commonly worked on.

When removing covers which are under internal pressure or under pressure from a spring, always leave two bolts in position on opposite sides. Slowly release the pressure, then slowly loosen the bolts to remove.