Chapter 4:
Hydraulic System Fundamentals . . . . 61
The Basics of Hydraulic Systems 62
Incompressibility of Liquids / Transfer of Movement /
Changes in Force / Pascal’s Law
A Simple Brake Hydraulic System 63
Master Cylinder / Wheel Cylinders and Calipers /
Lines and Hoses / Control Valves
Basic Anti-Lock Brake Hydraulics 65
Brake Fluid 66
Brake Fluid Standards / Types of Brake Fluids
Chapter 5:
Master Cylinders, Calipers,
and Wheel Cylinders . . . . . . . . . . . . . 71
Overall Hydraulic System 72
Brake Pedal Linkage 72
Master Cylinder 72
Hydraulic Systems / Master Cylinder Components /
Master Cylinder Operation—Normal Braking /
Master Cylinder Operation during
Hydraulic System Failure
Quick Take-up Master Cylinder 80
Quick Take-up Design / Quick Take-up Operation—
Brake Apply / Quick Take-up Operation—Brake
Release / Master Cylinders Used with Anti-lock
Brake Systems / Single Master Cylinder
Disc Brake Calipers 82
Cylinder and Piston Construction / Caliper Designs /
Electric Calipers
Wheel Cylinders 84
Wheel Cylinder Construction and Operation /
Bleeder Screws
Chapter 6:
Master Cylinder, Caliper, and Wheel
Cylinder Service . . . . . . . . . . . . . . . . 91
Master Cylinder Service 92
Checking Master Cylinder Condition / Checking
Pedal Travel / Master Cylinder Removal / Master
Cylinder Disassembly / Cleaning and Inspection /
Honing / Master Cylinder Reassembly /
Master Cylinder Installation
Caliper Service 97
Checking Caliper Condition / Caliper Removal /
Caliper Disassembly / Cleaning and Inspection /
Honing Calipers / Caliper Reassembly /
Caliper Installation
Wheel Cylinder Service 101
Checking Wheel Cylinder Condition / Wheel
Cylinder Removal / Wheel Cylinder Disassembly /
Cleaning and Inspection / Honing Wheel
Cylinders / Wheel Cylinder Reassembly /
Wheel Cylinder Installation
Bleeding the Brakes 105
Manual Bleeding / Pressure Bleeding /
Bleeding the Master Cylinder /
Gravity Bleeding
Brake Flushing 107
Chapter 7:
Power Assist Units . . . . . . . . . . . . . . 111
The Need for Power Assist Units 112
Types of Power Assist Units
Vacuum Power Assist Units 112
Basic Vacuum Power Assist Operation / Vacuum
Unit Construction / Vacuum Unit Operation /
Vacuum Sources
Hydraulic Power Assist Units 120
Hydro-boost / Hydro-boost Components /
Hydro-boost Operation / Powermaster /
Powermaster Components / Powermaster Operation /
Power Brake Assist in ABS Systems
Chapter 8:
Power Assist Unit Service . . . . . . . . 129
Repair or Replace? 130
Vacuum Power Assist Service 130
Checking Vacuum Power Assist Condition /
Common Vacuum Booster Problems /
Checking and Adjusting Pushrod Length /
Vacuum Booster Removal / Vacuum
Booster Overhaul / Vacuum Booster
Installation / Vacuum Pump Service
Hydro-boost Service 138
Checking Hydro-boost Condition / Common
Hydro-boost Problems / Hydro-boost
Removal / Hydro-boost Overhaul /
Hydro-boost Installation / Flushing
and Bleeding Hydro-boost Units
Powermaster Service 143
Powermaster Diagnostics / Powermaster
Repair
Chapter 9:
Hydraulic Valves, Switches, Lines,
and Hoses . . . . . . . . . . . . . . . . . . . . 151
Pressure Control Valves and Switches 152
Metering Valve / Proportioning Valve / Residual
Pressure Valve / Pressure Differential Valve /
Combination Valve / Low Brake Fluid Switch /
Hill Holder / Brake Light Switch
Brake Lines and Hoses 158
Steel Brake Lines / Flexible Hoses / Brake Fittings
Chapter 10:
Hydraulic Valve, Switch, Line,
and Hose Service . . . . . . . . . . . . . . 165
Hydraulic Valve Service 166
Hydraulic Valve Problems / Testing the Operation
of Hydraulic System Valves / Testing Pressure Hold
Valves / Testing Valves with Pressure Gauges
Electrical Switch Service 170
Testing Low Brake Fluid Switches / Testing Brake
Light Switches
Table of Contents 5