Suspension Specialists - Technical Bulletin Number 5

Air Brake Troubleshooting Guide
Table of Contents
	Air Brake Fundamentals
	Typical Air Brake Schematic Air Brake Components Component Troubleshooting
	Air Brake Troubleshooting
	Truck, Tractor and Bus Troubleshooting Trailer Troubleshooting Air Drier Troubleshooting

Typical Truck/Tractor Air Brake Schematic

Position the mouse over an item for a brief description,
click on an item for a detailed description.

Typical Truck/Tractor Air Brake Components
Component	Function
Air Compressor	Supplies air under pressure necessary for proper function of all brake components. Compressor capacities vary, which is determined by several factors including vehicle use and air brake system requirements. Back to the Schematic
Air Drier	Removes moisture and contaminants from the air system. Air driers are mounted inline between the compressor and the first (wet) air tank. Moisture is automatically purged from the system when the air governor cycles (unloads) the compressor. Back to the Schematic
Anti-Compound Control Line	Descriptive text goes here. Back to the Schematic
Dash Gauge	Descriptive text goes here. Back to the Schematic
Double Check Valve w/ Stop Light Switch	Descriptive text goes here. Back to the Schematic
Foot Valve	Descriptive text goes here. Back to the Schematic
Front Brake Reservoir	Descriptive text goes here. Back to the Schematic
Front Service Brake Chamber	Descriptive text goes here. Back to the Schematic
Governor	Descriptive text goes here. Back to the Schematic
Limiting and Quick Release Valve	Descriptive text goes here. Back to the Schematic
Low Pressure Switch	Descriptive text goes here. Back to the Schematic
One Way Check Valve	Descriptive text goes here. Back to the Schematic
Rear Brake Reservoir	Descriptive text goes here. Back to the Schematic
Safety Valve	Descriptive text goes here. Back to the Schematic
Service Brake Relay Valve	Descriptive text goes here. Back to the Schematic
Slack Adjuster	Descriptive text goes here. Back to the Schematic
Spring Brake Control/Relay Valve	Descriptive text goes here. Back to the Schematic
Spring Brake Valve	Descriptive text goes here. Back to the Schematic
Supply Reservoir	Descriptive text goes here. Back to the Schematic
Tandem Spring Brake Assembly	Descriptive text goes here. Back to the Schematic
Tractor Park Valve	Descriptive text goes here. Back to the Schematic
Tractor Protection Valve	Descriptive text goes here. Back to the Schematic
Tractor-Trailer Park Valve	Descriptive text goes here. Back to the Schematic
Trailer Charge Dash Valve	Descriptive text goes here. Back to the Schematic
Trailer Emergency Gladhand	Descriptive text goes here. Back to the Schematic
Trailer Emergency Supply	Descriptive text goes here. Back to the Schematic
Trailer Hand Control	Descriptive text goes here. Back to the Schematic
Trailer Service Gladhand	Descriptive text goes here. Back to the Schematic
Trailer Service Supply	Descriptive text goes here. Back to the Schematic
Two Way Check Valve	Descriptive text goes here. Back to the Schematic

Truck, Tractor and Bus Troubleshooting

Insufficient Brakes
1. Brakes need adjusting, lubricating or relining.
2. Low air pressure in the brake system (below 60psi).
3. Brake valve delivery pressure below normal.
4. Wrong size actuators and/or slack adjusters.
5. Failure of part of a dual air system.
6. If remote mounted brake valve - check linkage.
Brakes Apply Too Slowly
1. Brakes need adjusting of lubricating.
2. Low air pressure in the brake system (below 60psi).
3. Insuffcient brake valve delivery pressure.
4. Excessive leakage with brake applied.
5. Restricted tubing or hose.
6. Treadle (brake pedal) travel restricted.
7. If remote mounted brake valve - check linkage.

Trailer Troubleshooting

Air Drier Troubleshooting

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