Dozers & Excavators

Learn to:

Interpret complex dozer and excavator schematics
Test for correct horsepower limiting pump control function
Verify normal and faulted propel systems
Describe valve pilot and load sense functions
Measure flows in regenerative implement functions

In this customized course, heavy duty mechanics, heavy equipment technicians, shop leaders, planners and reliability specialists learn the typical circuits and operating parameters for dozers and excavators. Various sub-circuits from a Caterpillar 385/390C and from the Hitachi Zaxis model line are covered with on-screen simulations. Plenty of schematic reading practice is offered through worksheets and Live Schematics.

This four-day course is taught with circuit simulation software, machinery schematics and on-screen simulations, and through instructor guided, hands-on study of live hydraulic components.

Drawing on materials from our courses How to Maintain & Troubleshoot Hydraulic Systems and Advanced Mobile with Load Sense Hydraulic Troubleshooting, participants learn to maintain and troubleshoot dozer and excavator systems for maximum availability and reliability. A method of analysis for determining faults is taught, as is our Ten Step Troubleshooting Process. Schematic reading and safe work practices are core topics throughout.

Attachment and Implement System

Objective: Analyze implement valve banks and pump controls

Activities: Work out flow paths for dozer blade and boom lift circuits

Know the bucket float and blade quick drop functions cold

Load Sense Troubleshooting and Proportional Valve Bank

Objective: Explain the features of common load sense directional valves

Activities: Test anti-cavitation, port relief and pilot functions

Differentiate between valve inlet side and outlet side, pressure compensators

Dozer and Excavator Undercarriage Propel

Objective: Describe typical undercarriage propel and steering clutch circuits

Activity: Analyze typical travel function problems

Solve uneven tracking issues

Excavator Swing Circuit

Objective: Interpret swing circuit functions

Activities: Set up and test swing brake valves

Solve swing over-run problems

Pump Controls

Objective: Describe piston pump control systems in use

Activities: Measure standby and margin pressures

Know your horsepower/torque limiting controls

Electrical Circuit Schematics

Objective: Analyze electro-hydraulic component functions

Activities: Identify components and connections by their symbols

Know the valve signals and how to measure them

Safety

Objective: List common hydraulic hazards and safe procedures

Activities: Inspect system components for failures

Work safely around high pressure circuits

Where does this class fit in?

Dozers & Excavators is a specialty construction and mining class, along with Loaders & Graders. If you enjoyed this class, consider taking your troubleshooting further with our general hydraulics course, How to Maintain & Troubleshoot Hydraulic Systems.

CD Industrial Group Inc.