Portland Community College | Portland, Oregon

Course Number:
AM 151
Course Title:
Undercar Systems I
Credit Hours:
Lecture Hours:
Lecture/Lab Hours:
Lab Hours:
Special Fee:

Course Description

Introduces principles of automotive braking systems. Includes practicing disassembly/assembly of brake system components using school owned equipment including proper measuring and machining of brake drums and discs. Prerequisites: CG 209. Audit available.

Addendum to Course Description

This course is designed for students with no previous industry experience. Students will develop the skills, knowledge and attitudes necessary to perform, with supervision, base (non anti-lock) brake and anti-lock brake (ABS) repairs on import and domestic cars and light trucks. This course will prepare students for Brakes II (AM115), where they will practice learned skills on customer vehicles until they can diagnosis and repair brake systems with limited supervision. This is the skill level necessary for employment at an apprentice level.

The broader purpose of this course is to provide students, at the beginning of their first year in the automotive program, with authentic experience in basic industry skills and concepts, to ensure their success in later courses and on-the-job. These skills include tool use, fastener tightening, and ASE style test taking. Concepts and attitudes that they will put into practice include safety, craftsmanship, professionalism and responsible customer service.

Intended Outcomes for the course

Perform a complete vehicle brake inspection, including measurement and evaluation of the base brake friction, hydraulic, wheel bearing, parking brake and power assist components.
Perform brake drum and rotor refinishing.
Demonstrate professional, safe and ethical practice in the performance of brake repair.

Outcome Assessment Strategies

To reach these goals, students will demonstrate the course outcomes for Brakes I by completing the following tasks:

1. Perform a complete brake inspection and service.

This is the capstone performance for Brakes I, done near the end of the course. Preparation for this performance will be the completion of the
following sub-tasks in labs throughout the course:

Overhauling drum and disc brake systems
Servicing brake hydraulic components
Servicing conventional wheel bearings
Performing repairs to correct brake vibration
Performing power assist brake diagnosis
Adjusting parking brake systems
Identify an ABS system by its major characteristics and perform
ABS service and diagnostic tests

2. Demonstrate professional skills and attitudes throughout AM 105 by:

Maintaining good attendance
Using safe shop procedures
Demonstrating respect for other students and school property
Participating in and completing all required activities

3. Demonstrate preparedness for ASE testing by achieving passing scores on all written exams

Major concepts

Critical to the effective diagnosis and repair of any automotive system is an understanding of how and why certain components work. On today's automobile, this is often more useful for the technician than the ability to perform a particular adjustment or replacement. A technician must also have the ability to determine which repairs are in the customer's best interest, and understand how safe service procedures are in their own best interest. To develop this background understanding of automotive brake systems, students in AM 105 will explore the following concepts:

Health and safety

Hazards of brake dust, importance of shop cleanliness
Hazards of chemicals used in brake systems and repair

Professional business and personal conduct

Customer safety
Repeat repairs
Communicating with customers
Customer satisfaction as business strategy
Cooperative problem solving
Work absence and attendance

Physical laws

Energy transfer
Heat and Friction
Hydraulic theory - Pascals law

Specific system and component operation

Hydraulic - caliper, wheel cylinder, master cylinder, quick-take-up
Master cylinder, control valves, ABS, brake fluids, brake lines
Disc brakes - floating, fixed, low drag, phenolic, parking brake calipers
Drum brakes - servo, non servo, self-adjusting
Power assist - vacuum, Powermaster, Hydroboost
Parking brakes
ABS brake operation - modes of operation, sensors, OBD, limitations

Skills developed in AM 105

In Brakes I, students will build an inventory of the following repair skills to prepare for a career as a brake technician. Further skills will be developed and all skills will be practiced in AM 115.

Hydraulic systems

Evaluate and overhaul wheel cylinders
Evaluate and overhaul Master cylinders
Evaluate and overhaul calipers
Measure and adjust master cylinder push rods
Bench bleed master cylinders
Adjust brake switches
Inspect flexible brake lines for wear
Flare and bend steel brake line
Bleed brakes using gravity, manual, pressure, and vacuum methods
Bleed an ABS system / front and rear hydraulic circuits
Diagnose control valve malfunctions
Properly select, handle, and install brake fluid and dispose used fluid

Drum brakes

Measure and evaluate lining thickness
Evaluate hardware condition
Replace linings, using safe procedures
Service backing plate
Perform major adjustment, and parking brake adjustment
Remove, clean, measure, evaluate and machine brake drums
Disc brakes
Measure and evaluate lining thickness
Replace pads, remove and install pad/caliper hardware
Service sliding mechanism
Measure and evaluate rotors for thickness, run-out, and parallelism
Refinish rotors
Overhaul calipers

Wheel bearings

Service conventional wheel bearings
Adjust conventional wheel bearings
Inspect and replace wheel studs
Remove an reinstall sealed bearing assembly

Power brakes

Perform and evaluate power booster function test
Perform power booster leak test

Parking brake systems

Diagnose parking brake problems
Adjust parking brakes

Base brake diagnosis

Identify and interpret brake system concerns and necessary action
Research applicable vehicle service information
Use vehicle identification numbers

ABS Brakes

Evaluate a Wheel Speed Sensor for open circuit, air gap, tone ring and EMI failures
Depressurize a high pressure ABS type system
Bleed an ABS system (all circuits) using the recommended scanner
Determine number of wheel speed sensors, hydraulic channels, and
type of OBD on a given ABS system; describe OBD parameters
Perform manual ABS code retrieval and erase code
Perform ABS code retrieval and erase code using a scanner
Perform Scanner live data and auto-test

Note: The process skills necessary to diagnose and repair ABS systems are developed in Brakes II. Assessment of these skills is done in Brakes II.

Related Instruction

Hours: 6


1. Perform a complete vehicle brake inspection", including measurement and evaluation of the base brake friction, hydraulic, wheel bearing, parking brake and power assist components.
2. Perform brake drum and rotor refinishing.


Students measure brake rotors and drums compare vehicle test results to manufactures specifications.
Students measure brake pad and shoe linings compare vehicle test results to manufactures specifications.

Hours: 2


1. Perform a complete vehicle brake inspection, including measurement and evaluation of the base brake friction, hydraulic, wheel bearing, parking brake and power assist components.


Students work teams communicate with staff to check out tools, school cars, and have repair orders written for lab projects.
Students present a verbal report to the class on a subject of their choice related to current industry technical advances, innovations, safety standards, and/or diagnostic or trouble shooting procedures related to steering and/or suspension.

Human Relations
Hours: 15


1.  Demonstrate professional, safe and ethical practice in the performance of brake repair.


Students work in teams to complete assigned lab projects.
Students work in teams and staff members to bring school cars in /out of the shop for class lab projects.