FM 5-499

HYDRAULICS

Table of Contents

LIST OF FIGURES AND TABLES

CHAPTER 1. Hydraulic Basics

1-1. Pressure and Force.

1-2. Pascal's Law

1-4. Energy, Work, and Power

Potential Energy

Heat Energy and Friction

Relationship Between Velocity and Pressure

CHAPTER 2. Hydraulic Systems

2-1. Basic Systems

Motor-Reversing System

Open-Center System

Closed-Center System

2-2. Color Coding

2-3. Reservoirs

Ventilation and Pressurization

Line Connections

2-4. Strainers and Filters

2-5. Filtering Material and Elements

2-6. Accumulators

Spring-Loaded Accumulator

Bag-Type Accumulator

Piston-Type Accumulator

2-7. Pressure Gauges and Volume Meters

Pressure Gauges

2-8. Portable Hydraulic-Circuit Testers

Improper Operation

2-9. Circulatory Systems

Flexible Hosing

2-10. Fittings and Connectors

Threaded Connectors

Flared Connectors

Flexible-Hose Couplings

Reusable Fittings

CHAPTER 3. Pumps

3-1. Pump Classifications

Nonpositive-Displacement Pumps

Positive-Displacement Pumps

Characteristics

3-2. Performance

3-3. Displacement

Fixed-Displacement Pump

Variable-Displacement Pump

Centrifugal Pump

Reciprocating Pump

3-6. Gear Pumps

3-7. Vane Pumps

Characteristics

Unbalanced Vane Pumps

Balanced Vane Pumps

Two-Stage Pumps

3-8. Piston Pumps

Axial Piston Pumps

3-9. Pump Operation

Operating Problems

CHAPTER 4. Hydraulic Actuators

Single-Acting Cylinder

Double-Acting Cylinder

Differential Cylinder

Nondifferential Cylinder

Ram-Type Cylinder

Piston-Type Cylinder

Cushioned Cylinder

Lockout Cylinders

4.2 Construction and Application

4-3. Maintenance

External Leakage

Internal Leakage

Creeping Cylinder

Sluggish Operation

Lack of Lubrication

Abrasives on a Piston Rod

Burrs on a Piston Rod

4-4. Hydraulic Motors

Gear-Type Motors

Vane-Type Motors

Piston-Type Motors

CHAPTER 5. Valves

5-1. Pressure-Control Valves

Pressure-Reducing Valves

Sequence Valves

Counterbalance Valves

Pressure Switches

5-2. Directional-Control Valves

Sliding-Spool Valve

Four-Way Valves

5-3. Flow-Control Valves

Orifice Check Valve

5-4. Valve Installation

Meter-In Circuit

Meter-Out Circuit

Bleed-Off Circuit

Compensated Flow

5-5. Valve Failures and Remedies

Servicing Valves

Disassembling Valves

Repairing Valves

5-6. Valve Assembly

5-7. Troubleshooting Valves

Pressure-Control Valves

Directional-Control Valves

Volume-Control Valves

CHAPTER 6. Circuit Diagrams and Troubleshooting

6-1. Hydraulic-Circuit Diagrams

Cutaway Diagram

Pictorial Diagram

Graphical Diagram

6-2. United States of American Standards Institute (USASI) Graphical Symbols

Pressure-Control Valves

Flow-Control Valves

Directional-Control Valves

6-3. Typical Mobile Circuits

Hydraulic-Lift Circuit

Power-Steering Circuits

Road-Patrol-Truck Circuits

6-4. Troubleshooting

Causes of Improper Operations

Testing a Hydraulic Circuit

Comparing Test Results with Specifications

Flow and Pressure

Other Conditions

Specific Troubles, Causes, and Solutions

CHAPTER 7. Electrical Devices: Troubleshooting and Safety

7-1. Hydraulics and Electricity

7-2. Troubleshooting Electrical Devices

Testing Devices

Chassis or Common Ground

Zero Reference Point

Isolation Between Earth and Chassis Ground

APPENDIX A. Metric Conversion Chart