ASE Brakes

Core Brake Diagnostic Testing & Symptoms

100

Core Brake Diagnostic Testing & Symptoms:

PEDAL IS SPONGY = Air in system

Caused By:

1.

2.

• Air in the hydraulic system
• Contaminated or moisture-laden brake fluid

200

Pascal’s Law & Hydraulic Principles:

Pressure applied to a confined fluid is transmitted __________ throughout the fluid.

equally

300

Brake Fluid Testing:

Contaminated fluid indicators:

1.

2.

3.

• Dark or discolored fluid
• Excessive moisture content
• Visible debris or particles

400

Core Brake Diagnostic Testing & Symptoms:

PEDAL IS HARD/HIGH EFFORT = Power-assist problem

Caused by:

1.

2.

3.

• Failed power booster
• Loss of vacuum supply to a vacuum booster
• Defective booster check valve

500

Core Brake Diagnostic Testing & Symptoms

PEDAL GOES TO FLOOR = Hydraulic system problem

Caused by:

1.

2.

3.

• Master cylinder internal leakage or failure

     * External hydraulic leak from a line, hose, wheel cylinder, or caliper

• Excessive brake shoe or pad clearance caused by worn or improperly adjusted components

Brake System Component Inspection Procedures

100

Drum Brake Measurements:

Component/Measurement: Drum after refinishing

Specification/Action: Must not exceed __________ specification

Maximum or Discard

200

Drum Brake Measurements:

Component/Measurement: Brake shoe adjustment

Specification/Action: __________ before installing drum

Pre-Adjust

300

Disc Brake Measurements:

Component/Measurement: Rotor thickness

Tool/Specification: Measure with __________

Micrometer

400

Disc Brake Measurements:

Component/Measurement: Caliper piston on integrated parking brake

Tool/Specification: Must __________ and re-adjust

Retract

500

Drum Brake Measurements:

Component/Measurement: Wheel cylinder inspection

Specification/Action: Check for __________ and proper operation

Leaks

Diagnostic Testing Procedures

100

Master Cylinder Testing:

Measure brake pedal __________, __________, and free play.

height, travel

200

Master Cylinder Testing:

Bench bleed procedure: Install the __________ before reinstalling the master cylinder.

bench-bleed kit fittings and hoses (or block-off plugs)

300

Power Booster Testing:

Test procedure: Check pedal travel with the engine __________ and __________.

off, running

400

Power Booster Testing:

Vacuum source: Engine __________ or auxiliary pump.

vacuum

500

Brake Line Inspection:

Inspect brake lines, flexible hoses, and fittings for:

1. Leaks

2.  _______

3. Kinks

4. _____________

5. Cracks

6. ___________

7. Wear

 Dents, Rust or Corrosion, Bulging

Electronic Brake Control Systems

100

ABS Component Identification:

ABS stands for? 

Anti lock Braking System

200

ABS Component Identification:

ESC stands for?

Electronic Stability Control

300

ABS Diagnosis:

Retrieve __________ __________ __________ (DTCs) and freeze-frame data.

Diagnostic Trouble Codes

400

ABS Diagnosis:

Check sensor signal for:

1. Output signal

2. ____________

3. Shorts to voltage or ground

4. ____________

Resistance

Frequency data

500

Speed Sensor Testing: 

Frequency data: ______________________________________ 

Confirm that frequency changes appropriately as wheel speed changes.

Related Systems

100

Wheel Bearing Service:

Tapered roller bearings: Remove, clean, inspect, __________, and __________.

repack,  install or adjust.

200

Wheel Bearing Service:

Sealed wheel bearings: Remove, reinstall, or __________ the entire assembly.

replace

300

Parking Brake Service:

Check components for wear, _________ , and corrosion.

 binding 

400

Parking Brake Service:

Service includes cleaning, __________, and adjusting.

lubricating

500

Brake Warning Light System:

Identify __________ of the hydraulic brake warning light system.

components