COMPETENCY – BASED
LEARNING
MATERIALS
Sector
:
Qualification Title:
Unit of Competency:
Module Title:
AUTOMOTIVE
AUTOMOTIVE SERVICING NC II
SERVICE BRAKE SYSTEM
OVERHAUL BRAKES
HOW TO USE THIS COMPETENCY BASED LEARNING MODULE?
Welcome!
The unit of competency, "Service Brake System" is one of the
competencies of Automotive Servicing NC II; a course which comprises the
knowledge, skills and attitudes required for an Automotive Technician to
possess.
This unit of competency contains knowledge, skills and attitudes
required for Automotive Servicing NC II. This module contains training
materials and activities for you to complete.
You are required to go through a series of learning activities in order
to complete each learning outcome of the module. In each learning
outcome are Information Sheets, Self-Checks and Job Sheets. Follow these
activities on your own. If you have questions, don’t hesitate to ask your
instructor for assistance.
Recognition of Prior Learning (RPL)
You may already have some or most of the knowledge and skills
covered in this learner's guide because you have been working for some
time already completed training in this area.
If you can demonstrate to your trainer that you are competent in a
particular skill or skills, talk to him/her about having them formally
recognized so you don't have to do the same training again. If you have a
qualification or Certificate of Competency from previous trainings, show it
to your trainer. If the skills, you acquired are still current and relevant to
the unit/s of competency they may become part of the evidence you can
present for RPL. If you are not sure about the currency of your skills,
discuss this with your trainer.
This module was prepared to help you achieve the required
competency in “Service Brake System”.
This will be the source of information for you to acquire knowledge
and skills in this particular competency independently and at your own
pace, with minimum supervision or help from your instructors.
Most probably your trainer will also be your supervisor or manager.
He/she is there to support you and show you the correct way to do things.
Your trainer will tell you about the important things you need to
consider when you are completing activities and it is important that you
listen and take notes.
You will be given plenty of opportunity to ask questions and practice
on the job. Make sure you practice your new skills during regular work
shifts. This way you will improve both your speed and memory and also
your confidence.
REMEMBER TO:
 Work through all the information and complete the activities in each
section.
 Talk to your trainer and agree on how you will both organize the
Training of this unit. Read through the module carefully. It is divided
into sections, which cover all the skills, and knowledge you need to
successfully complete this module.
 Read information sheets and complete the self-check. Suggested
references are included to supplement the materials provided in this
module.
 Use the Self –Check and Job Sheets at the end of each section to
test your own progress.
 Talk to more experience workmates and ask for their guidance.
When you feel confident that you have had sufficient practice, ask
your instructor to evaluate you. The results of your assessment will be
recorded in your Progress chart and Accomplishment Chart.
PRE REQUISITE:
Basic and Common Competencies
AUTOMOTIVE SERVICING NC II
LIST OF COMPETENCIES
NO. UNIT OF COMPETENCY
MODULE TITLE
CODE
1.
Service Automotive
Battery
Servicing Automotive Battery
ALT723303
2.
Service Ignition System
Servicing Ignition System
ALT723304
3.
Test and Repair
Wiring/Lighting System
Testing and Repairing
Wiring/Lighting System
ALT723305
4.
Service Starting System
Servicing Starting System
ALT723307
5.
Service Charging System
Servicing Charging System
ALT723308
6.
Service Engine
Mechanical System
Servicing Engine Mechanical
System
ALT723309
7.
Service Clutch System
Servicing Clutch System
ALT723310
8.
Service Differential and
Front Axle
Servicing Differential and
Front Axle
ALT723311
9.
Service Steering System
Servicing Steering System
ALT723312
10.
Service Brake System
Servicing Brake System
ALT723314
11.
Service Suspension
System
Servicing Suspension System
ALT723315
12.
Perform Underchassis
Preventive
Maintenance
Performing
Underchassis Preventive
Maintenance
ALT723306
13.
Overhaul Manual
Transmission
Overhauling Manual
Transmission
ALT723313
UNIT OF COMPETENCY
:
SERVICE BRAKE SYSTEM
MODULE TITLE
:
OVERHAULING BRAKE SYSTEM
MODULE DESCRIPTOR
:
This module deals with servicing brake
system. It also includes diagnosing,
adjusting and repairing brake mechanism.
NOMINAL DURATION
:
24 hours
SUMMARY OF LEARNING OUTCOMES:
Upon completion of this module, the trainee/student must be able
to:
LO1. Pull-out/mount brake system components
LO2. Disassemble/assemble brake system components.
LO3. Conduct road test.
LO1. PULL-OUT/MOUNT BRAKE SYSTEM COMPONENTS
ASSESSMENT CRITERIA:
1. Brake system components are pulled out/mounted.
2. Brake system assemblies are accurately tagged/ marked.
CONTENTS:






Operating principles of brake system
Brake system types and components
Hydraulic brake system fluid
Changing hydraulic fluid
Personal safety procedures
Service procedures
CONDITIONS:
Students/trainees must be provided with the following:












Well ventilated workshop
Vehicle
Air compressor/air gun
Wheel wedge
Set of automotive hand tools
Hand gloves
Apron
Brake fluid
Rags
Service manual
Reference book
CDs
METHODOLOGIES:




Interactive discussion
Demonstration
Self-paced instruction
Video presentation
ASSESSMENT METHODS:




Interview
Written examination
Practical demonstration
Direct observation
LO2. DISASSEMBLE/ASSEMBLE BRAKE SYSTEM COMPONENTS
ASSESSMENT CRITERIA:
1.
2.
3.
4.
5.
Component parts accurately tagged/marked.
Parts properly rinsed with specified cleaning solutions.
Damaged parts identified and replaced.
Assembled brake system component is tested.
Personal safety procedure followed.
CONTENTS:




Procedure in dismantling brake system component
Assembling brake components in accordance with standard
Applying personal safety in disassembling hydraulic parts
Using accurate tools for the job.
CONDITIONS:
Students/trainees must be provided with the following:














Vehicle
Well ventilated workshop
Washing pan
Air compressor/air gun
Hydraulic jack
Tire wrench
Set of automotive hand tools
Hand gloves
Apron
Brake fluid
Clean rags
Service manual
Reference books
CDs
METHODOLOGIES:



Interactive discussion
Demonstration
Self-paced instruction
ASSESSMENT METHODS:




Interview
Written examination
Practical demonstration
Direct observation
LO3. CONDUCT ROAD TEST
ASSESSMENT CRITERIA:
1. Pre-starting check-up is performed prior vehicle operation.
2. Vehicle driven at specified speed to detect brake trouble.
3. Findings are recorded and recommendation is given.
CONTENTS:





Pre starting check-up
Brake troubles
Driving techniques
Vehicle safety requirements.
Adjusting/setting emergency/parking brakes
CONDITIONS:
Students/trainees must be provided with the following:


Running condition vehicle
Driving range
METHODOLOGIES:



Interactive discussion
Demonstration
Self-paced instruction
ASSESSMENT METHODS:




Interview
Written examination
Practical demonstration
Direct observation
LEARNING OUTCOME SUMMARY
Unit of Competency
1
Learning Outcome
#1
Overhauling brake system
Pull out/mount brake system components
ASSESSMENT CRITERIA:
1. Brake system components are pulled out/mounted.
2. Brake system assemblies are accurately tagged/ marked.
CONTENTS:






Operating principles of brake system
Brake system types and components
Hydraulic brake system fluid
Changing hydraulic fluid
Personal safety procedures
Service procedures
CONDITIONS:
Students/trainees must be provided with the following:











Well ventilated workshop
Vehicle
Air compressor/air gun
Set of automotive hand tools
Hand gloves
Apron
Brake fluid
Rags
Service manual
Reference book
CDs
METHODOLOGIES:



Interactive discussion
Demonstration
Self-paced instruction
ASSESSMENT METHODS:




Interview
Written examination
Practical demonstration
Direct observation
LEARNING EXPERIENCES
Learning Outcome 1: Pullout/mount brake system component
Learning Activities
Special Instructions
1. Read Information sheet 10.1-1 on
Operating principles of brake system,
Read
and
understand
the
types and components
information sheet and then answer
the self-check and compare your
2. Answer Self-Check 10.1-1
answer to the self-check answer
Compare answer to the self-check answer key.
key 10.1-1
You need to answer all questions
3. Read Information Sheet 10.1-2 on
correctly before proceeding to the
hydraulic system brake fluid
next information sheet.
4. Answer Self-Check 10.1-2
Compare answer to self-check answer
In performing the task sheets,
key 10.1-2
assess/evaluate your work with the
performance criteria checklist and
5. Read Information Sheet 10.1-3 on
then
make
the
necessary
safety instruction on how to operate a 2corrections and improvements.
post lift/hoist
6. Perform Operation Sheet 10.1-1 on
how operate a 2- post lift/hoist
Evaluate
performance
using
Secure the evaluation of your
outputs by your trainer and let
him/her
record
your
accomplishment.
Performance Criteria Checklist
7. Read information sheet 10.1-4 on
preparing vehicle for service and inspection
Upon completion of these
Answer self-check 10.1-4
activities, you may proceed to the
Compare answer to self -check answer
next Learning Outcome.
key 10.1-4
Perform Job Sheet 10.1-1 on preparing
vehicle for service and inspection
8. Read Information Sheet 10.1-5 on
brake disassembly procedures
Answer self-check 10.1-5
Compare answers to self-check
answer key 10.1-5
Perform Job Sheet 10.1-2 on how to
pull out and tag brake component parts
Evaluate performance
Performance Criteria Checklist
using
Information Sheet 10.1-1
Operation of Brake System, Types and Components
Learning Objectives:
After reading this INFORMATION SHEET, YOU MUST be able to:
1. Identify disc brake components and its definitions, functions and
operation.
2. Identify drum brake components and its definitions, functions and
operation.
3. Understand the different types of Disc and Drum brakes.
Base Brake Components
Base Brake Components Include the following:
• Service brake pedal and pedal linkage
• Power brake boost system
• Master cylinder
• Cables, hoses, pipes and parking brake
• Brake rotors and pads
• Brake drums and shoes
• Brake balance controls (proportioning valve and metering valve),
if equipped
• Red BRAKE Warning Lamp (RBWL) and other warning systems
Base brake components are the parts of the brake system found on
all vehicles (Figure 10.1-1.1). The term “base brakes” does not
include antilock brakes or traction control systems
Figure 10.1-1.1 : Brake Components
Brake System Operation
Brakes slow and stop a vehicle when the brake linings contact the
drums or rotors using friction to convert kinetic energy to heat
energy. The intensity of the heat is proportional to the vehicle speed
and the degree of deceleration. Faster speeds and quicker stops
equal more heat.
Today's high performance hydraulic brake systems have been
developed over many years, through a constant evolution of design
and component improvements.
Base Brake ‐ Sub‐Systems
The brake system includes components in several different sub‐
systems (Figure 10.1-1.2)
• Apply system
• Boost system
• Hydraulic system
• Wheel brakes
• Balance control system
• Warning system
Figure 10.1-1.2: Brake sub- systems
Stopping a vehicle requires that all brake sub‐systems act together.
Apply system ‐ The driver presses the brake pedal, operating the
pedal linkage.
Boost system ‐ The brake booster (if equipped) increases the brake
pedal force Hydraulic system ‐ The pedal force moves the pistons
in the master cylinder, forcing out pressurized brake fluid. The brake
fluid is directed through pipes and hoses to the wheel brakes.
Wheel brakes ‐ At the wheel, the pressurized brake fluid moves
pistons. The pistons press brake friction material against a spinning
rotor or drum, slowing the vehicle.
Balance control system ‐ Hydraulic and mechanical valves ensure
that brakes apply quickly, simultaneously and at balanced pressure
for safest operation. Warning system ‐ An instrument panel lamp
signals the driver of brake system failure. Because of innovations in
materials and technology, there is a wide variety of components
specific to each of these base brake component systems.
Disc Brake Type: The major components of disc brake are the
rotor, caliper and brake pads (Fig 10.1-1.3).
Disc brakes have a caliper that clamps two
brake pads against a rotor (Figure 10.1-1.4),
Some rotors have cooling fins between the
two braking surfaces that circulate air
between the braking surfaces, making them
less sensitive to heat build up and more
resistant to brake fade (temporary reduction
of brake effectiveness resulting from heat).
Figure 10.1-1.3 Caliper Assembly
Figure 10.1-1.4: Brake caliper assembly
CALIPER ASSEMBLY: The
Caliper assembly is located
over the rotor. It converts
the hydraulic pressure
received through the brake
lines and hoses from the
master
cylinder
to
mechanical action that
pushes the brake pads
against the rotor
Caliper Types:
• Single‐piston and dual‐piston floating
or sliding calipers
• Rear calipers with integral parking brake function
. Single Piston and Dual Piston Calipers
Single and dual piston calipers essentially operate in the same way
(Figure 10.1-1.5). In the dual piston design, two pistons provide more
piston surface area in a smaller package.
Both single and dual piston calipers use a floating design.
In the floating caliper, the piston is on the inboard side of the caliper.
When the brakes are applied, the caliper moves along either: • The
Mounting bolts, or....
• Machined guides on the caliper and mounting bracket (see Figure
10.1-1.6).
Figure 10.1-1.5: Single and Dual piston calipers
Figure 10.1-1.6: Machined guide caliper
ROTOR: The rotor is mounted on the wheel
hub. It provides braking surface for the pads
to push against. Friction between the pads and
rotor stops the vehicle when the brake is
applied. Brake rotors are the rotating
components of the disc brake system that
comes in contact with the lining material from
the brake pads. The rotor is made of cast iron
or a composite of cast iron and steel.
Figure 10.1-1.7. Rotor
Figure 10.1-1.8 Brake Pads
BRAKE PADS: Brake pad is a steel plate with friction
material attached to its surface. Brake pads are
located at both sides of the rotor inside the calipers
of disk brake. When the brakes are applied the pads
are forced against the rotor surface. When pushed
against the rotor, the pads create friction which stops
the vehicle. Brake linings are designed and tested for
specific vehicle applications, the brake friction
coefficient of Single Piston Disc Brake the pad
material is vehicle matched to optimize brake
operation and wear characteristics.
Disc brake operation
When the driver applies the brakes:
1. Fluid pressure behind the piston presses against the caliper
piston and the piston bore .
2. The piston pressure forces the pad against the inboard rotor
surface. Pressure applied to the piston bore forces the caliper to move
on its slides.
3. Caliper movement applies pressure against the outboard brake
pad, forcing the pad against the rotor surface.
4. Both brake pads press against the rotor surfaces, bringing the
vehicle to a stop.
Figure 10.1-1.9. Fluid flow when brakes are applied
Figure 10.1-1.10. Brake operation with brake pedal is released
Drum brakes
There are two main types of drum brakes, Duo servo and leading
trailing. In the duo servo application, the primary brake shoe transfer
force to the secondary brake shoe during braking. The secondary
brake shoe is longer and thicker than the primary brake shoe
because the secondary shoe contributes more braking power. In
leading-trailing applications, the leading brake shoe provides most
of the braking power. The trailing shoe contributes braking power
only when the wheels slows down.
Duo servo drum brakes
Duo servo brakes (see fig. 10.1-1.7) are called self - energizing
because the secondary shoe is applied by forced generated from the
primary brake shoe and multiplied by the adjuster screw.
Duo servo brake components description and operation
1. Anchor pin – it is attached to the backing plate and prevent the
shoes from rotating with the drum.
2. Secondary shoe – the secondary shoe is moved against the drum
by the forced exerted by the primary brake shoe and adjuster screw
when the brake is applied. The lining on the secondary shoe is
usually longer and thicker than the primary shoe lining.
3. Adjuster screw – It multiples and transfers force from primary
brake shoe to the secondary brake shoe. It is not attached to the
brake drum and moves with the primary and secondary brake shoes.
4. Connecting spring - it holds the primary and secondary brake
shoes against the adjuster screw.
5. Primary brake shoe – is the first shoe to come in contact with the
drum during forward braking. As it contacts the drum it is forced in
contact with the adjusting screw which multiplies and transfers
energy to the secondary shoe. The lining is usually shorter than the
secondary shoe lining.
6. Wheel cylinder assembly – pushes the brake shoe by converting
the hydraulic pressure from brake lines and hoses into
mechanical force
7. Return springs – holds the brake shoes away from the brake
drum until the brakes are applied.
8. Hold down pin and spring – it keeps the brake shoes aligned with
the backing plate.
Figure 10.1-1.11: Duo- servo drum brake
Operation of duo servo during braking
Duo‐Servo Drum Brake In the duo‐servo unit, braking forces
increase (energize) in both forward and reverse motion (refer to
Figure 10.1-1.11a) The energizing force transfers from one shoe to
the other when the wheel rotates in either direction. A wheel cylinder
actuates both the primary (front) and secondary (rear) brake shoes.
Return springs hold the upper end of each shoe against a single
anchor. An adjusting screw assembly and spring connect the lower
ends of the shoes. Duo‐Servo Operation The wheel cylinder mounts
on the backing plate at the top of the brake. When the brake pedal
is depressed (Figure 10.1-1.11a).
1. Hydraulic pressure in the wheel cylinder forces both pistons
outward to apply the brakes.
2. When the primary (forward) brake shoe contacts the rotating
drum, the frictional forces drag the shoe and turn it outward from
its pivot points.
3. The shoe is energized when it wedges into the drum with a force
greater than the hydraulic pressure applied to the wheel cylinder.
4. The rotational force from the primary shoe transfers through the
adjusting screw to the secondary shoe.
5. The shoe wedges against the drum with the same energizing
action as the primary shoe.
6. The secondary shoe overcomes the wheel cylinder force and
returns the secondary shoe to the anchor pin.
The secondary shoe performs more of the braking. Therefore, the
secondary brake lining is usually thicker and has more surface area
than the primary brake lining.
In duo servo applications, when the vehicle is moving forward and
the brake is applied, the wheel cylinder forces the primary shoe into
the drum. The primary shoe rotates with the drum moving into the
adjuster which multiples the braking force. This force energizes the
secondary brake shoe forcing it against the anchor and against the
drum. Friction between the shoes and drum slows the vehicle. If the
vehicle is in reverse when the brake is applied, the secondary shoe
contacts the drum first and then energizes the primary shoe. See
Figure 10.1-12a and 12b.
Figure 10.1-1.12a: Brake
applied
Figure 10.1-1.12b:
Brake released
Leading and trailing drum brake
Referred to as non - servo because it does not use an adjuster
screw to multiply the braking force’ In the leading‐trailing type of
drum brake, the leading shoe performs the greater portion of the
braking. Leading‐trailing brakes have a fixed anchor at the bottom
of the brake backing plate (Figure 10.1-1.13).
Leading – trailing components description and
operation
1. Wheel cylinder – applies the brake shoes by converting
hydraulic pressure from the brake lines into mechanical force.
2. Wheel cylinder boots - located at both ends of the wheel
cylinder to prevent entry of dirt and moisture. It also prevents
minor fluid leaks from reaching the brake linings.
3. Leading shoe and lining – the first shoe to come in contact
with the brake drum during forward braking and provides most
of the braking power.
4. Parking brake actuating arm – activated by the parking brake
cable and forces the brakes shoes against the drum when the
parking brake is set.
5. Anchor plate – connected to the bottom of the brake shoes and
prevents the shoes from rotating with the drum.
6. Trailing shoe and lining – second shoe to contact the brake
drum during forward braking. Provides braking power when the
wheels begin to slow down.
7. Adjuster screw assembly – adjusts the clearance between the
shoes and the brake drum. It compensates for the lining wear to
prevent excessive pedal travel.
8. Return spring - holds the brake shoes away from the brake
drum until the brakes are applied.
9. Hold down pin and spring – it keeps the brake shoes aligned
with the backing plate.
10. Shoe to anchor return spring – located near the anchor
plate, used to hold the brake shoes against the anchor plate.
Leading-trailing brake operation:
On brake application during forward motion:
1. Wheel cylinder forces the lining of the leading (forward) shoe
into contact with the rotating drum.
2. Friction between the drum and lining energizes the leading
shoe and places pressure against the anchor pin at the bottom of
the shoe. The forward shoe rotates outward until the drum
prevents further outward movement.
3. The wheel cylinder also actuates the trailing (rear) shoe.
Rotational force does not energize the trailing shoe. The friction
force is the same as the input force from the wheel cylinder.
Figure 10.1-1.13: Leading-trailing drum brake
REFERENCES/FURTHER READING
Crouse, William H. and Anglin, Donald L.; Automotive Mechanic; 10th
ed.; McGraw
Hill International Edition, 2004.
GM service technical training book (CD, SWG)
Self-Check 10.1-1
Multiple choice: Write the letter of the best answer on the blank space
provided before each number.
____1. Which of the following is NOT a main component of a disk brake?
a)
Caliper
c) rotor
b)
Brake pads
d) drum
____2. Which component shown in the figure provides a surface for the
pads to press against?
a)
b)
1
2
c) 3
d) 4
____3. What is the component shown?
in the figure?
a)
b)
c)
d)
Brake pad
Caliper
Brake shoe
Rotor
____4. In disc brake application, the caliper
piston presses the __________ against the spinning rotor.
a) Brake shoes
b) Brake pads
c) brake drum
d) brake disc
___5. Two technicians are discussing a leading-trailing drum brake.
Technician A says that the primary brake shoe transfers force to the
secondary brake shoe during braking. Technician B says that the
secondary brake shoe contributes more braking power. Who is
correct?
a) Technician A
b) Technician B
c) both technician A and B
d) neither technician A nor B
Matching type: Duo servo drum brake. Match the name of the
components at the column A to the correct description or function at
column B. Write your answer to space provided before each number.
COLUMN A
___1. Connecting spring
COLUMN B
A) pushes the brake shoe by
converting hydraulic pressure
into mechanical force.
___2. Wheel cylinder
B) holds the brake shoes away
from the brake drum until the
brakes are applied.
___3. Secondary shoe
C) prevents the shoes from
rotating with the drum.
___4. Return spring
D) during forward braking, it
contacts the drum first.
___5. Anchor pin
E) holds the primary and
secondary brake shoes against
the adjusting screw
___6. Adjusting screw
F) multiplies and transfers the
brake force from the primary
to the secondary brake shoe.
___7. Primary shoe
G) during forward braking, it is
energized by the adjusting
screw.
PARTS IDENTIFICATION. Place the name of the components of a
leading-trailing drum brake to its correct location.
Answer Key 10.1-1
MULTIPLE CHOICE:
1.
2.
3.
4.
5.
d
b
b
b
d
MATCHING TYPE
1.
2.
3.
4.
5.
6.
7.
E
A
G
B
C
F
D
IDENTIFICATION
Information Sheet 10.1-2
Brake Hydraulic System Brake Fluid
Learning Objectives:
After reading this INFORMATION SHEET, YOU MUST be able to:



Identify and Describe the different brake fluid types used in
the hydraulic system.
Describe and enumerate the fluid flow in the brake system
Observe safety precautions in handling brake fluid
Hydraulic System ‐ system that delivers pressurized fluid to the
brake assembly at each wheel.
Major Components (Fig. 10.1-2.1)
• Fluid reservoir
• Hydraulic master cylinder
• Balance control systems
• Brake pipes and hoses
• Calipers and wheel cylinders
Figure 10.1-2.1. Typical hydraulic system
Figure 10.1-2.2 Hydraulic fluid distribution
Brake Fluid
Brake fluid is used in all hydraulic system. It is specially formulated
fluid that enables braking system to function. It is not a compressible
liquid therefore transmits force to braking components when brake
pedal is applied.
Brake fluids are hygroscopic, meaning that it will absorb water
readily which will decrease the fluids boiling point. Boiling brake
fluid will cause bubbles to form in the closed hydraulic system and
could potentially cause a brake failure.
Silicone brake fluids do not absorb water by diffusion and are
therefore non‐hygroscopic. These fluids do have other disadvantages
in that they will absorb free water in fluid form (non‐diffused) which
will form pockets of water vapor (bubbles) when the temperature is
raised above 100C (212F) and alternately when the temperature
becomes less than freezing the free water will solidify causing
restriction and poor braking performance. Silicone fluids carry
contaminants in solution and can cause ports and vents to
eventually plug.
Characteristics of brake fluid
Must remain stable over a wide range of
temperature
•
Help maintain smooth braking system
•
High boiling point over 400 degree F (204
degree C)
•
Low freezing point down to -50 degree F (45.56 degree C)
•
Figure 10.1-2.3 Types Hydraulic
fluid
High boiling point

Figure
10.1-2.4
Hydraulic
fluid
characteristics (high boiling point)
Figure 10.1-2.5 Hydraulic fluid characteristics
(low freezing point)
A great deal of heat energy is
generated during braking
operation. This heat enters the
hydraulic system. Brake fluid
must not boil and transform
into vapor because
Vapor does not transmit motion
and pressure and force the way
liquid does. If the brake fluid
boils and turns into a vapor, the
brake system will fail. Therefore,
brake fluid must have a high
boiling point.
Low freezing point
The brake fluid must have
a low boiling point. If the
brake fluid thickens when
its exposed to cold
temperatures, it will not
transmit the pressure
from the brake pedal
properly and the brakes
will not function as
intended.
Brake fluids come into contact with a number of
parts. They must not corrode metal or deteriorate rubber brake
components such as the cylinder pistons and seals. In fact, the fluid
should be able to lubricate those components.
Brake fluid inherently absorb moisture while in the hydraulic
system. Because of this, two boiling points are listed for brake fluid.
The dry boiling point indicates the boiling point of brake fluid without
moisture. The wet boiling point indicates the boiling point of brake
fluid with moisture. The wet boiling point is always lower than the
dry boiling point.
The exact amount of water allowed in the brake fluid and how the
boiling point is determined are covered in standards issued by
Society of Automotive Engineers (SAE) and Federal Motor Vehicle
Safety Standards (FMVSS). The fluids are normally referred to by
their Department of Transportation (DOT) numbers. The primary
types of brake fluid are DOT3, DOT4, DOT5 and DOT5.1.
DOT3 brake fluid characteristics
 Natural polyglycol fluid
 Clear to light amber color





Absorb moisture
Dry boiling point is 401 degree F
Wet boiling point is 284 degree F
Used in most domestic vehicles and almost half of imported
vehicles
Can damage interior and exterior automotive paint finishes
DOT4 brake fluid characteristics
 Natural polyglycol fluid
 Clear to light amber color
 Absorbs moisture
 Dry boiling point is 446 degree F
 Wet boiling point is 311 degree F
 Used in many domestic and imported vehicles
 Can damage interior and exterior automotive paint finishes
DOT5 brake fluid characteristics
 Synthetic, silicone brake fluid
 Purple appearance
 Does not absorb moisture in the air
 Dry boiling point is 500 degree F
 Wet boiling point is 356 degree F
 Non-corrosive to hydraulic system components
 Compresses slightly under pressure causing a spongy brake
pedal feel
 Retains more air compared to DOT3, DOT4 and DOT 5.1
 Does not damage interior and exterior automotive paint
finishes
DOT








5.1 brake fluid characteristics
Synthetic non- silicone polyglycol based brake fluid
Designed specifically for ABS brakes
Clear to light amber in color
Used in severe duty and high performance vehicles
Absorbs moisture
Dry boiling point is 500 degree F
Wet boiling point is 356 degree F
Can damage interior and exterior automotive paint finishes
Currently higher DOT numbers indicate higher boiling point. Under
ideal conditions meaning a clean sealed system the lower numbered
brake fluids last longer.
Figure 10.1-2.6 Hydraulic fluid
WARNING
You should never mix silicone and polyglycol brake fluids. DOT 5 will
not mix with DOT 3, DOT 4 and DOT 5.1 brake fluids. It will float on
top, compromising brake efficiency and possibly causing injuries.
Additionally using DOT 5 in systems designed for DOT 3, DOT 4 or
DOT 5.1 can cause the rubber seals to swell resulting in improper
brake operation. Mixing DOT 3 and DOT 4 together will lower the
boiling point of the mixture, reducing brake pressure and creating a
safety hazard. Its best to use the brake fluid specified by the vehicle
manufacturer. If you need to replace a contaminated fluid be sure to
thoroughly flush the system before changing it.
Figure 10.1-2.7 Hydraulic fluid interactions
Brake fluid flow
1. When the brake pedal is applied, fluid in the reservoir flows
through the master cylinder and exits through master cylinder
ports.
Figure 10.1-2.8a Hydraulic fluid flow
2. Fluid flows through two independent circuits
Figure 10.1-2.8b Hydraulic fluid flow
3. Fluid flows to front and rear brakes regulated by metering,
proportioning or combination valve through pipes and hoses.
Figure 10.1-2.8c Hydraulic fluid flow
4. Fluid is delivered at appropriate pressure and timing to brake
calipers and/or wheel cylinders if vehicle has rear drum brakes.
Figure 10.1-2.8d Hydraulic fluid flow
5. Fluid causes brake calipers and wheel cylinders to apply and
vehicle stops.
Figure 10.1-2.8e Hydraulic fluid flow
SAFE HANDLING OF BRAKE FLUIDS
Contamination During Service
Corrosion and particles in the brake hydraulic system quickly
destroy the sealing effectiveness of pressure cylinders (master
cylinder, wheel cylinder, and caliper). Careful work habits during
hydraulic service will help prevent contamination of the hydraulic
system. Brake fluid can damage painted surfaces. Remember to use
care when handling fluids around vehicle fenders etc.
Hydraulic System ‐ Contamination Avoidance Techniques
• Use only clean DOT 3 or DOT 4 brake fluid when assembling
hydraulic components
• Never use petroleum‐based cleaners for hydraulic components, use
only approved brake cleaning products such as denatured alcohol
• Do not dry components with lubricated shop air
• Service hydraulic components on a clean work bench, away from
grinders, sanders and other particle‐generating equipment
• Store brake fluid in a sealed container. Brake fluid absorbs
moisture, moisture and water can damage hydraulic components
REFERENCES/FURTHER READING
Crouse, William H. and Anglin, Donald L.; Automotive Mechanic;
10th ed.; McGraw
Hill International Edition, 2004.
GM service technical training book (CD, SWG)
Self - Check 10.1-2
Multiple choice: Write the letter of the best answer on the blank
space provided before each number.
___1. Which of the following brake fluid has the lowest boiling
point?
a. DOT 3
c. DOT 5
b. DOT 4
d. DOT 5.1
___2. Which statement about DOT 3 brake fluid is TRUE?
a. it does not absorb moisture
c. it is a natural
polyglycol fluid
b. it is dark brown in color
d. it is a synthetic-based
fluid
___3. The main purpose of the hydraulic system is to deliver
_________ fluid to the brakes at each wheel.
a. vaporized
c. cooled
b. pressurized
d. heated
___4. Fluid flows through ____ independent hydraulic circuit/s.
a. 1
c. 3
b. 2
d. 4
___5. The _________ is the temperature at which brake fluid will
boil if it contains no moisture.
a. wet boiling point
c. sub-freezing point
b. dry boiling point
d. dry freezing point
Alternative Response (True or False). Read the following
statement about brake fluids and determine if it is either True or
False. If the statement is True write T before the number and if the
statement is False write F on the space provided before the number.
___1. Must remain stable over wide range of temperature.
___2. Enables braking system to function
___3. Typically brake fluids have a low boiling point up to 200
degrees F
___4. DOT 3 is highly compressible
___5. Specially formulated fluid
Chronological Sequencing Test:
Arrange in correct sequence the fluid flow in a hydraulic
brake system. Write the sequence number before each statement.
___ Fluid flows to the front and rear brakes regulated by metering,
proportioning or combination valve.
___ Fluid is delivered at appropriate pressure and timing to the
brake calipers and wheel cylinders.
___ Fluid in reservoir flows through the master cylinder.
___ Fluid flows through 2 independent circuits of pipes and hoses.
___ Fluid causes the brake calipers and wheel cylinders to apply
and the vehicle stops.
Answer key 10.1-2
Multiple choice.
1.
2.
3.
4.
5.
a
c
b
b
b
Alternative response (True or False).
1.
2.
3.
4.
5.
T
T
F
F
T
Chronological sequencing.
1.
2.
3.
4.
5.
3
4
1
2
5
Information Sheet 10.1-3
SAFETY INSTRUCTIONS IN OPERATING 2 POST LIFTS
Daily inspect your lift. Never operate if it malfunctions or if it has
broken or damaged parts. Use only qualified lift service personnel
and genuine parts to make repairs.
• Thoroughly train all employees in use and care of lift, using
manufacturer’s instructions and “Lifting It Right” and “Safety Tips”
supplied with the lift.
• Never allow unauthorized or untrained persons to position vehicle
or operate lift.
• Prohibit unauthorized persons from being in shop area while lift is
in use.
• Do Not permit anyone on lift or inside vehicle when it is either
being raised or lowered.
• Always keep area around lift free of tools, debris, grease and oil.
• Never overload lift. Capacity of lift is shown on nameplate affixed
to the lift.
• Do Not stand in front of the vehicle while it is being positioned in
lift bay.
• Do Not hit or run over lift arms or adapters. This could damage
lift or vehicle. Before driving vehicle into lift bay, position arms and
adapters to provide unobstructed entrance onto lift.
• Load vehicle on lift carefully. Position lift adapters to contact at
the vehicle manufacturer’s recommended lift points. Raise lift until
adapters contact vehicle. Check adapters for secure contact with
vehicle. Raise lift to desired working height.
DO NOT go under vehicle if locking latches are not engaged.
• Do Not block open or override self-closing lift controls; they are
designed to return to the “Off” or Neutral position when released.
• Do Not remove or disable arm restraints.
• Remain clear of lift when raising or lowering vehicle.
• Always use safety stands when removing or installing heavy
components.
• Avoid excessive rocking of vehicle while on lift.
• Clear area if vehicle is in danger of falling.
• Remove tool trays, stands, etc. before lowering lift.
• Release locking latches before attempting to lower lift.
• Position lift arms and adapters to provide an unobstructed exit
before removing vehicle from lift area.
Figure 10.1-3.1 Safety instructions
signs
Figure 10.1-3.2 Warning
OPERATION SHEET 10.1-1
Title:
Operate a 2 post lift/hoist
Performance Objective: Given a vehicle pull out brake components, you
should be able to use a 2 post hoist to lift and
lower the vehicle following manufacturer’s
manual.
Supplies/Materials
: 2 post lift operation manual
Equipment
: 2 post lift and training vehicle
Steps/Procedure:
1. Gather instruction and relevant materials
2. Read and follow manufacturer’s manual safety precautions
3. Identify the parts of the 2 post lift
4. Lift the vehicle, follow the steps listed below:
A. Before Loading: Lift must be fully lowered and service bay clear of all
personnel before the vehicle is brought on lift. Swing arms out to full drivethru position.
B. Spot vehicle over lift. Make sure you are using the correct adapter,
Fig. 10.1-1.1
C. Loading: Swing arms under vehicle and position adapters at vehicle
manufacturer’s recommended lift points, Fig. 10.1-1.2. Use intermediate,
high step, or optional adapters for under body clearance when required.
D. To Raise Lift:
a. Push Raise switch on power unit, Fig. 10.1-1.3.
b. Stop before making contact with vehicle. Check arm restraint pins for
engagement. If required, slightly move arm to allow restraint gear and
pawl to mesh. DO NOT hammer pin down as this will damage the
restraint gear teeth.
c. Raise vehicle until tires clear the floor.
d. Stop and check adapters for secure contact at vehicle manufacturer’s
recommended lift points.
e. Continue to raise to desired height only if vehicle is secure on lift.
f. Do Not go under vehicle if all four adapters are not in secure contact at
vehicle manufacturer’s recommended lift points.
g. Repeat complete spotting, loading and raising procedures if required.
h. Lower lift onto locking latches.
Adapter Recommendations
Fig, 10.1-1.1
Adapter recommended for
vehicles with chassis frame,
stub frame and perimeter
frame vehicles
Adapter recommended for
lifting unibody vehicles
Fig. 10.1-1.2 Typical lifting points
Figure 10.1-1.3 lift’s power unit
5. To Lower Lift:
A. Remove all tools or other
objects from lift area.
B. Raise lift off locking
latches.
C. Pull latch release handle
fully and hold.
D. Push lowering valve
handle to lower, Fig. 10.11.3.
Assessment Method:
Practical Demonstration
Direct Observation
Performance Criteria Checklist 10.1 - 1
CRITERIA
Did I….
1. Gathered instruction and relevant materials?
2. Read and followed manufacturer’s manual safety
precautions?
3. Identified the parts of the 2 post lift ?
4. Lifted the vehicle properly, following the steps?
5. Lowered the vehicle following the correct procedures?
YES
NO
Information Sheet 10.1-4
Prepare vehicle for service and Inspect brake components
Learning Objectives:
After reading this INFORMATION SHEET, YOU MUST be able to:
•
•
•
Prepare vehicle for service
Inspect brake component failures
Apply safety precautions when performing the task
Before any repair or inspection is done on the vehicle, the vehicle
should be prepared.
Procedure in preparing the vehicle for service.
1. Check the brake fluid. If the brake
fluid is above the ADD mark and you
know that the pads will be replaced
drain the fluid to the ADD mark by
opening the caliper bleeder screws.
Figure 10.1-4.1 checking brake fluid
2. Raise the vehicle on a hoist or stand.
Be sure to follow appropriate safety
precautions. See operations and safety
manual.
Figure 10.1-4.2 raise vehicle on a
lift/hoist
3.
Remove the lug nuts and the
wheel and tire assembly.
Note: Vacuum or wet clean the assembly
to remove any debris. To avoid breathing
brake dust do NOT use air hose or dry
brush for cleaning
Figure 10.1-4.3 remove lug nuts
After the vehicle is prepared, you can now inspect the brake
components.
Inspecting brake assembly
Figure 10.1-4.4
1. CALIPER - Check the
caliper for damage, it
should move smoothly
Figure 10.1-4.5
2. BRAKE LINES/HOSES
- Check the lines and
hoses for leaks, cracks,
splits and swelling.
Figure 10.1-4.6
3. ROTOR - Check rotors
for excessive surface
,scoring, thickness
variation or lateral runout
REFERENCES/FURTHER READING
Crouse, William H. and Anglin, Donald L.; Automotive Mechanic;
10th ed.; McGraw
Hill International Edition, 2004.
GM service technical training book (CD, SWG)
SELF CHECK 10.1-4
Chronological Sequencing Test:
Arrange in correct sequence in preparing a vehicle for
inspection. Write the sequence number before each statement.
____ Raise the vehicle on a hoist or stand. Be sure to follow
appropriate safety precautions. See operations and safety manual.
____ Remove the lug nuts and the wheel and tire assembly.
____ Check the brake fluid. If the brake fluid is above the ADD
mark and you know that the pads will be replaced drain the fluid to
the ADD mark by opening the caliper bleeder screws.
Enumeration:
Enumerate what to check in the following brake components
1. Caliper assembly
a)
__________________________________________________________________
____
b)
__________________________________________________________________
____
2. Brake lines/hoses
a)
__________________________________________________________________
____
b)
__________________________________________________________________
____
c)
__________________________________________________________________
____
d)
__________________________________________________________________
____
3. Rotor
a)
__________________________________________________________________
____
b)
__________________________________________________________________
____
Answer key to SELF CHECK 10.1-4
Chronological sequence
3
2
1
Enumeration
1.
a) check for any damage
b) caliper should move smoothly
2.
a) check for leaks
b) check for cracks
c) check for splits
d) check for swelling
3.
a) check for excessive scoring
b) check for thickness variation or lateral runout
JOB SHEET 10.1-1
Title:
Position and raise the vehicle for inspection
Performance Objective: Given a vehicle to inspect, you should be able to
position and raise the vehicle following safety
precautions.
Supplies/Materials : Info sheet 10.1-4, 2 post lift operation manual
Equipment : 2 post lift , training vehicle
Steps/Procedure:
1.
2.
Prepare tools and equipment to be use
Move and position the vehicle
3.
Select appropriate adapter for the vehicle
4.
Swing the arm to the correct lift point on the vehicle
5.
Operate 2 post hoist to raise the vehicle
6.
Check vehicle stability
7.
Prepare vehicle for service
8.
Inspect brake assembly
Assessment Method:
Demonstration & Direct observation
Performance Criteria Checklist 10.1 - 1
CRITERIA
Did I….
1. Identified and prepared all the equipment and
materials to be used?
2. Moved and position vehicle in the middle of the lift?
YES


3. Selected the appropriate adapter for the vehicle?

4. Placed the swing arm at the proper lift point of the
vehicle?
5. Operated the lift as per manuals instructions?

6. Checked vehicle stability?


7. Prepared the vehicle for service

8. Inspected brake assembly for defects/damages

NO
Information Sheet 10.1-5
Pull-out and tag brake components
Learning Objectives:
After reading this INFORMATION SHEET, YOU MUST be able to:
•
•
•
Disassemble disc brake components
Disassemble drum brake components
Apply safety precautions when performing the task
Disc Brake disassembly procedure
1. Remove caliper by
removing mounting
pins or bolts
2. Lift and rotate caliper
assembly from the
rotor
3. Remove brake pads
4. Suspend caliper from
under body
with
wire
Drum brake disassembly procedure
1. Remove the brake shoe return
spring
using brake spring tool or
screw driver
to twist and pop the spring off
2. Push and turn the brake shoe
hold down springs then
remove them
3. Remove the primary shoe and
lining
4. Remove the parking brake
cable and actuating arm from
shoe
5. Remove the secondary brake
shoe and lining
REFERENCES/FURTHER READING
Crouse, William H. and Anglin, Donald L.;
Automotive Mechanic; 10th ed.; McGraw
Hill International Edition, 2004.
GM service technical training book (CD, SWG)
Self- check 10.1-5
Chronological Sequencing Test:
Arrange in correct sequence in disassembling disc brake
components. Write the sequence number before each statement.
_____
_____
_____
_____
Remove caliper by removing mounting pins or bolts
Remove brake pads
Lift and rotate caliper assembly from the rotor
Suspend caliper from under body with wire
Answer key to self - check 10.1-5
1
3
2
4
JOB SHEET 10.1-2
Title: Pull out and tag brake components
Performance Objective:
Given a vehicle with abnormal noise during
braking, you should be able to inspect the brake
components following the standard procedure and
safety precautions.
Supplies/Materials : Service manual, Information sheet 10.1-5
Equipment
 2 post lift,
 Training vehicle,
 personal protective equipment
 Air compressor/impact gun
 Set of hand tools
 Brake fluid container
 Rags
 Service manual
 2 post lift operation manual
:
Steps/Procedure:
1. Prepare your PPE (Personal Protective Equipment) and tools
needed
2. Follow the disassembly procedures in the information sheet
10.2-3.
3. Tag all the brake components after disassembly is done.
4. Organize the equipment and tools used.
Assessment Method: Demonstration with oral questioning
Performance Criteria Checklist 10.1-2
CRITERIA
Did I….
1. Prepared all the equipment and materials needed?
2. Used your PPE’s for the job:
 Goggles

Proper Working Clothes

Safety Shoes

2 post hoist/lift

Training vehicle

Air compressor

Air impact gun

Hand tools set

Brake fluid and container

Rags

Service manual

Hoist operation manual
3. Positioned the vehicle in the middle of the lift?
4. Shifted the transmission to Park?
5. Lifted the vehicle?
6. Prepared the vehicle for service?
• Checked brake fluid level
• Raised the vehicle on the hoist
• removed wheel lugs and tire assembly
7. Disassembled the front disc brake assembly?
 Removed caliper mounting pins
YES
NO

Lifted and pull out caliper assembly

Removed brake pads

Supported caliper with wire

Tagged components
8. Disassemble rear drum brake components?
 Removed brake drum

Removed brake shoe return springs

Removed hold down pin and springs

Removed primary shoe and lining

Removed parking brake cable and actuator arm

Removed secondary brake shoe and lining

Tagged components