2007 FORD FIESTA light

206-00-3 Brake System - General Information 206-00-3
DIAGNOSIS AND TESTING
Brake System
The brakes system operates by transferring effort
applied to the brake pedal by the driver to the
brakes at each wheel.
The braking effort is distributed to each wheel,
using a hydraulic system. The system is assisted
using a vacuum brake booster that reduces pedal
effort and increases hydraulic pressure.
The parking brake operates on the rear wheels
and is applied using a hand operated control.
lnspection and Verification
N0TE:Before carrying out any diagnosis, make
sure that the brake system warning indicator is
functional.
1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical
damage.
3. If an obvious cause for an observed or reported
concern is found, correct the case (if possible)
before proceeding to the next step.
4. If the cause if not visually evident, verify the
symptom and refer to the Symptom Chart.
Visual lnspection Chart
Road Test
1.
Perform a road test to compare actual vehicle
braking performance with the performance
standards expected by the driver. The ability of the
test driver to make valid comparisons and detect
performance deficiencies will depend on
experience.
Mechanical
- Tire pressure
- Wheels and tires
- Fluid leak from brake line(s)
The driver should have a thorough knowledge of
the brake system operation and accepted general
performance guidelines to make good comparisons
, and detect performance concerns.
An experienced technician will always establish a
route that will be used for all brake diagnosis road
tests. The road selected will be reasonably smooth and level. Gravel
or bumpy roads are not suitable
because the surface does not allow the tires to grip
the road equally. Crowned roads should be avoided
because of the large amount of weight shifted to
the low set of wheels on this type of road. Once
the route is established and consistently used, the
road surface variable can be eliminated from the
test results.
Before a road test, get a complete description of
the customer concerns or suspected condition.
From the description, the technician will be able to
match possible causes with symptoms. Certain
components will be identified as possible sources
while others will be eliminated by the evidence.
More importantly, the customer description can
reveal unsafe conditions which should be checked
or corrected before a road test. The description will
also help form the basic approach to the road test
by narrowing the concern to specific components,
vehicle speed or conditions.
Begin the road test with a general brake
performance check. Using the description of the
concern, test the brakes at different vehicle speeds
using both light and heavy pedal pressure.
Determine if the concern is in the front or rear
braking system. First use the foot brake and then
the parking brake. If the condition
(i.e. pull,
vibration, pulsation) occurs only on operation of
the parking brake, the concern is in the rear brake
system.
If the condition occurs when the foot brake
is depressed, the concern is in the front brake
system.
Avoid locking the brakes and sliding the tires. This
condition will not indicate brake efficiency. A heavily
braked but turning wheel will stop the vehicle in a
shorter distance than locked wheels.
If the concern becomes evident during this check,
make sure it fits the description given before the
road test. If the concern is not evident, attempt to
duplicate the condition using the information from
the description.
If a concern exists, use the Brake System Symptom
Chart in order to isolate it to a specific sub-system
and condition description. From this description, a
list of possible sources can be used to further
narrow the cause to a specific component or
condition.
- -
2006.0 Fiesta 1212006 G28494en
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206-00-8 Brake System - General Information 206-00-8
DIAGNOSIS AND TESTING
Svm~tom Possible Sources Action
Pedal eases down slowly Air in the system.
Malfunctioning brake master
cylinder.
BLEED the brake system.
REFER to: (206-00 Brake
System
- General Information)
Brake System Bleeding (General Procedures),
Brake System Pressure Bleeding (General Proced-
ures).
GO to Pinpoint Test E.
Brake, Removal and Installa-
tion),
Brake Pads (206-03 Front Disc
Brake, Removal and Installa-
tion),
Brake Pads (206-04 Rear Disc
Brake, Removal and Installa-
Pedal is low or feels spongy
I tion). I
Brake lockup during light brake I
Worn brake shoes or brake
pads.
pedal force INSTALL new brake shoes or
brake pads. REFER to:
Hydraulic system.
Incorrect tire pressures.
Tires worn.
Glazed or worn brake shoes or
brake pads.
Brake booster.
GO to Pinpoint Test F. I
INFLATE the tires to the correct
pressure.
INSTALL new tires. I
brake pads. REFER to:
Brake Shoes (206-02 Drum
Brake, Removal and Installa-
tion),
Brake Pads (206-03 Front Disc Brake, Removal and Installa-
tion),
Brake Pads (206-04 Rear Disc
Brake, Removal and Installa-
tion).
GO to Pinpoint Test G.
Excessive or erratic pedal
travel Worn brake shoes or brake
pads. INSTALL new brake shoes or
brake pads. REFER to:
Brake Shoes (206-02 Drum Brake, Removal and Installa-
tion),
Brake Pads (206-03 Front Disc Brake, Removal and Installa-
tion),
I
Brake Pads (206-04 Rear Disc
Brake, Removal and Installa-
tion).
2006.0 Fiesta 1212006 G28494en
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206-00-9 Brake System - General Information 206-00-9
DIAGNOSIS AND TESTING
Symptom
Brakedrag
Excessive brake pedal effort
Brake noise
I
i
i
Slow or incomplete brake pedal
return Possible Sources
Action
Brake discs.
Brake booster.
Incorrectly adjusted brake light
switch. Brake pressure control valve.
Seized brake caliper or wheel
cylinder. Parking brake applied or
malfunction.
Seized parking brake cables.
Seized brake caliper slide pins.
Brake booster inoperative.
Worn or contaminated brake
shoes or brake pads.
Worn brake shoes or brake
pads.
Brake booster.
Brake booster.
Brake master cylinder.
GO to Pinpoint Test H.
GO to Pinpoint Test I.
ADJUST the brake light switch.
PERFORM a brake booster
functional test REFER to the
component tests.
INSTALL new brake shoes or
brake pads. REFER to:
Brake Shoes (206-02 Drum Brake, Removal and Installa-
tion),
Brake Pads (206-03 Front Disc
Brake, Removal and Installa-
tion),
Brake Pads (206-04 Rear Disc Brake, Removal and Installa-
tion).
GO to Pinpoint Test J.
INSTALL new brake shoes or
brake pads. REFER to:
Brake Shoes (206-02 Drum Brake, Removal and Installa-
tion),
Brake Pads (206-03 Front Disc
Brake, Removal and Installa-
tion),
Brake Pads (206-04 Rear Disc
Brake, Removal and Installa-
tion).
GO to Pinpoint Test K.
GO to Pinpoint Test L.
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206-00-1 4 Brake System - General Information 206-00-1 4
DIAGNOSIS AND TESTING
TEST CONDITIONS DETAILSIRESU LTSIACTIONS
C2: CHECK FOR REAR BRAKE VIBRATION
N0TE:With a manual release parking brake control, hold the parking brake control release button in
the release position during parking brake control application.
Road test the vehicle at 40-80 kmlh (25-50 mph)
with a medium application on the parking brake
control.
Is a vibration present?
-+ Yes
CHECK the rear brake drums or discs for
excessive wear. INSTALL new components
as necessary. REFER to:
Brake Drum (206-02 Drum Brake, Removal and
Installation),
Brake Shoes (206-02 Drum Brake, Removal and
Installation),
Brake Pads (206-04 Rear Disc Brake, Removal
and lnstallation),
Brake Disc (206-04 Rear Disc Brake, Removal
and Installation). TEST the system for normal operation.
I C3: CHECK FOR FRONT BRAKE VIBRATION I
Road test the vehicle at 40-80 kmlh (25-50 mph)
with light and medium application of the foot
brake.
Is a vibration present?
+ Yes
CHECK the front brake discs for excessive
wear or cracks. INSTALL new components as
necessary. REFER to: (206-03 Front Disc
Brake)
Brake Pads (Removal and lnstallation),
Brake Caliper (Removal and lnstallation).
TEST the system for normal operation.
+ No
Vehicle OK.
2006.0 Fiesta 12/2006 G28494en
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206-00-20 Brake System - General Information 206=00-20
DIAGNOSIS AND TESTING
TEST CONDITIONS
DETAILSIRESULTSIACTIONS
F4: BLEED THE BRAKE SYSTEM
rn Check for air in the brake system. Bleed the
brake system. REFER to: (206-00 Brake System
- General lnformation)
Brake System Bleeding (General Procedures),
Brake System Pressure Bleeding (General Procedures)
.
Is the condition still present?
+ Yes
GO to F5.
+ No
Vehicle OK.
F5: CHECK FRONT WHEEL HUB RETAINING NUT
Check the front wheel hub retaining nut for
looseness.
Is the front wheel hub retaining nut loose?
+ Yes
INSTALL a new front wheel hub retaining nut.
REFER to: Specifications (204-01 Front
Suspension, Specifications).
Do not reuse the
frontwheel hub retaining nut.
TEST the system for normal operation.
+ No
CHECK the parking bake adjustment. REFER
to: (206-05 Parking Brake and Actuation)
Parking Brake Cable Adjustment
- Vehicles With:
Rear Drum Brakes (General Procedures),
Parking Brake Cable Adjustment
- Vehicles With:
Rear Disc Brakes (General Procedures).
PINPOINT TEST G
: BRAKE LOCK UP DURING LIGHT BRAKE PEDAL FORCE
TEST CONDITIONS
DETAILSIRESULTSIACTIONS
I GI : ROAD TEST-THE VEHICLE I
Road test the vehicle and apply the brake pedal
lightly.
Do the rear brakes lock up?
+ Yes
GO to G2. GO to Pinpoint Test G.
+ No
Vehicle OK.
2006.0 Fiesta 12/2006 G28494en
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206-00-24 Brake System - General Information 206-00-24
DIAGNOSIS AND TESTING
TEST CONDITIONS DETAILSIRESU LTSIACTIONS
12: ROAD TEST THE VEHICLE
rn Road test the vehicle and apply the brakes.
Are the brakes functioning correctly?
-+ Yes
Vehicle OK.
+ No
INSPECT individual wheel cylinders or
calipers for binding or sticking components.
INSTALL new components as necessary.
BLEED the brake system. REFER to: (206-00
Brake System
- General Information)
Brake System Bleeding (General Procedures),
Brake System Pressure Bleeding (General Procedures).
TEST the system for normal operation.
PINPOINT TEST J
: EXCESSIVE BRAKE PEDAL EFFORT
TEST CONDITIONS
DETAILSIRESULTSIACTIONS
J1: CHECK BRAKE APPLICATION
With the engine off, apply and release the brake
pedal five times to deplete all vacuum from the
brake booster. Apply the brake pedal, hold with
light pressure. Start the engine.
Does the brake pedal hold?
+ Yes
GO to J2.
+ No
GO to J6.
52: CHECK BRAKE BOOSTER FOR LEAKS
rn Run the engine at medium idle, release the
accelerator pedal and turn the engine off. Wait
90 seconds and apply the brakes. Two or more
brake applications should be power assisted.
Does the brake booster work?
+ Yes
Vehicle OK.
-+ No
GO to
J3.
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206-00-29 Brake System - General Information 206-00-29
DIAGNOSIS AND TESTING
and repair the external leak. If the fluid level drops
and no external leak can be found, check for a
brake master cylinder bore end seal leak.
Brake System Check
Brake Pedal Reserve Check
Where a low brake pedal or the feel of a
bottomed-out condition exists, check for brake
pedal reserve.
1. Operate the engine at idle with the transaxle in
NEUTRAL.
2. Apply the brake pedal lightly three or four times.
3. Allow 15 seconds for vacuum to replenish the
brake booster.
N0TE:This increased resistance may feel like
something has bottomed out.
4. Apply the brake pedal until it stops moving
downward or an increased resistance to the
pedal travel occurs.
5. Hold the brake pedal in the applied position and
raise the engine speed to approximately 2000
rpm.
N0TE:The additional movement of the brake pedal
is the result of the increased engine intake manifold
vacuum which exerts more force on the brake
booster during engine rundown. This means that
additional stroke is available in the brake master
cylinder and the brake system is not bottoming out.
6. Release the accelerator pedal and observe that
the brake pedal moves downward as the engine
returns to idle speed.
Brake Booster Functional Test
lnspect all hoses and connections. All unused
vacuum connectors should be capped. Hoses and
their connections should be correctly secured and
in good condition with no holes and no collapsed 2.
With the transaxle in NEUTRAL, stop the engine
and apply the parking brake. Apply the brake
pedal several times to exhaust all vacuum in
the system.
3. With the engine turned off and all vacuum in the
system exhausted, apply the brake pedal and hold it down. Start the engine. If the vacuum
system is operating, the brake pedal will tend
to move downward under constant foot
pressure. If no motion is felt, the vacuum
booster system is not functioning.
4. Remove the vacuum hose from the brake
booster.
Intake manifold vacuum should be
available at the brake booster end of the hose
with the engine at idle speed and the transaxle
in NEUTRAL. Make sure that all unused vacuum
outlets are correctly capped, hose connectors
are correctly secured and vacuum hoses are in
good condition. When it is established that
manifold vacuum is available to the brake
booster, connector the vacuum hose to the
brake booster and repeat Step
3. If no
downward movement of the brake pedal is felt,
install a new brake booster. REFER to: (206-07
Power Brake Actuation)
Brake Booster
- LHD (Removal and lnstallation),
Brake Booster
- RHD (Removal and lnstallation).
5. Operate the engine a minimum of 10 seconds
at fast idle. Stop the engine and let the vehicle
stand for
10 minutes. Then, apply the brake
pedal with approximately 89
N (20 lb) force. The
pedal feel (brake application) should be the
same as that noted with the engine operating.
If the brake pedal feels hard (no power assist),
install a new vacuum check valve and then
repeat the test. If the brake pedal still feels hard,
install a new brake booster. REFER to: (206-07
Power Brake Actuation)
Brake Booster
- LHD (Removal and Installation),
Brake Booster
- RHD e em oval and installation).
If the brake pedal movement feels spongy, bleed
the brake system. REFER to: (206-00 Brake
System
- General Information)
areas. Inspect the check valve on the brake booster Brake System Bleeding (General Procedures),
for damage. Brake
System Pressure Bleeding (General
Procedures).
Brake Booster Operation Check
Brake Master Cylinder
1. Check the hydraulic brake system for leaks or
low fluid. Usually,
the first and strongest indicator of anything
wrong with the braking system is a feeling through
the brake pedal. In diagnosing the condition of the
brake master cylinder, check pedal feel as
2006.0 Fiesta 1212006 G28494en I
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Brake System - General Information
DIAGNOSIS AND TESTING
evidence of a brake concern. Check for the brake
warning indicator illumination and the fluid level in
the master cylinder reservoir.
Normal Conditions
The following conditions are considered normal
and are not indications that the brake master
cylinder is in need of service.
- Modern brake systems are not designed to
produce as hard a pedal effort as in the past.
Complaints of light pedal efforts should be
compared to pedal efforts of another vehicle, of
the same model and year.
- During normal operation of the brake the fluid
level in the reservoir will rise during brake
application and fall during release. The net fluid
level
(i.e., after brake application and release)
will remain unchanged.
- A trace of brake fluid will exists on the brake
booster shell below the master cylinder
mounting flange. This results from the normal
lubricating action of the master cylinder bore
end seal.
- The fluid level will fall with brake shoe and lining
wear.
Abnormal Conditions
N0TE:Prior to performing any diagnosis, make
sure the brake system warning indicator is
functional.
Changes in brake pedal feel or travel are indicators
that something could be wrong with the braking system. The diagnostic procedure and techniques
use brake pedal feel, warning indicator illumination
and low brake fluid level as indicators in diagnosing
braking system concerns. The following conditions
are considered abnormal and indicate that the
brake master cylinder is in need of service.
- The brake pedal effort is excessive. This may
be caused by a bind or obstruction in the pedal
.
or linkage, clogged fluid control valve or ( ' insufficient booster vacuum.
- The rear brakes lock up during light pedal force.
This may be caused by incorrect tire pressures,
grease or fluid on the brake shoes and linings,
damaged brake shoes and linings, incorrectly
adjusted parking brake, or damaged or
contaminated brake pressure control valves.
- The brake pedal effort is erratic. This condition
could be caused by a brake booster malfunction,
extreme caliper piston knock back or incorrectly
installed brake shoes and linings.
- The brake warning indicator is ON. This may
be caused by low fluid level, ignition wire routing
too close to the fluid level indicator assembly,
or float assembly damage.
Bypass Condition Test
1. Check the fluid in brake master cylinder. Fill the
brake master cylinder reservoir if low or empty.
2. Observe the fluid level in the brake master
cylinder reservoir. If after several brake
applications, the fluid level remains the same,
measure the wheel turning torque required to
rotate the wheels with the brakes applied as
follows:
Place the transaxle in NEUTRAL and raise and
support the vehicle. REFER to: (1 00-02 Jacking
and Lifting)
Jacking (Description and Operation),
Lifting (Description and Operation).
Apply the brakes with a minimum of 445 N (100
Ib) and hold for approximately 15 seconds. With
the brakes still applied, exert a torque on the front
wheels of 10.1 Nm (75
1b.R). If either wheel rotates,
install a new brake master cylinder. REFER to:
(206-06 Hydraulic Brake Actuation)
- The brake pedal goes down fast. This could be Brake Master Cylinder - RHD (Removal and
caused by an external or internal leak. Installation),
- The brake
pedal eases down slowly. This could Brake Master Cylinder - LHD
(Removal and
be caused by an external or internal leak. Installation).
- The
brake pedal is low and or feels spongy. This
condition may be caused by no fluid in the brake
Non-Pressure Leaks master cylinder reservoir, reservoir cap vent
holes clogged or air in the hydraulic system.
Any empty brake master cylinder reservoir
condition may be caused by two types of
non-pressure external leaks.
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