206-00-25 Brake System - General Information 206-00-25
DIAGNOSIS AND TESTING
TEST CONDITIONS
53: CHECK BRAKE BOOSTER CHECK VALVE
rn Disconnect the vacuum hose, for the brake
booster check valve at the intake manifold. Blow
into the hose attached to the brake booster
check valve.
Does air pass through the valve?
+ Yes
INSTALL a new brake booster check valve.
TEST the system for normal operation.
+ No
GO to J4.
54: CHECK BRAKE BOOSTER CHECK VALVE VACUUM
rn Disconnect the vacuum hose from the brake
booster check valve. Run the engine at idle.
Check the supply with a vacuum gauge.
Is the vacuum pressure above 40.5 kPa (12
in-Hg) with the brake booster non-operational?
+ Yes
GO to J5.
+ No
REPAIR or INSTALL a new vacuum hose and
fittings. TEST the system for normal operation.
55: CHECK BRAKE BOOSTER
rn Check the brake booster. GO to the component
test procedure in this section.
Is the brake booster OK?
+ Yes
GO to J6.
+ No
INSTALL a new brake booster. REFER to:
(206-07 Power Brake Actuation)
Brake Booster
- LHD (Removal and lnstallation),
Brake Booster
- RHD (Removal and lnstallation).
TEST the system for normal operation.
2006.0 Fiesta 1212006 G28494en
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206-00-26 Brake System - General Information 206-00-26
DIAGNOSIS AND TESTING
TEST CONDITIONS DETAILSIRESU LTSIACTIONS
I J6: CHECK BRAKE PEDAL LINKAGE If
rn Disconnect the actuator rod from the pedal pin
and apply the brake pedal fully.
Did the pedal move freely?
-+ Yes
GO to J7.
+ No
REPAIR or INSTALL new brake pedal bush-
ings. REFER to: (206-06 Hydraulic Brake
Actuation)
Brake Pedal
- LHD, Vehicles With: Manual
Transaxle (Removal and Installation),
Brake Pedal
- LHD, Vehicles With: 4-Speed
Automatic Transmission
(AW81-40), Vehicles
With: Automated Gearshift (Removal and
Installation),
Brake Pedal
- RHD (Removal and Installation).
TEST the system for normal operation.
157: CHECK BRAKE PRESSURE CONTROL VALVE I
rn Check the brake pressure control valve for
contamination.
Is the brake fluid contaminated?
+ Yes
INSTALL a new brake pressure control valve.
FILL the brake master cylinder reservoir.
BLEED the brake system. REFER to: (206-00
Brake System
- General Information)
1 Brake System Bleeding (General Procedures),
Brake System Pressure Bleeding (General
Procedures). TEST the system for normal operation.
1 * Ehicle OK.
2006.0 Fiesta 1212006 G28494en
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206-00-28 Brake System - General Information 206-00-28
DIAGNOSIS AND TESTING
PINPOINT TEST L : SLOW OR INCOMPLETE BRAKE PEDAL RETURN
TEST CONDITIONS
DETAILSIRESU LTSIACTIONS /"'
I L1: CHECK FOR BRAKE PEDAL RETURN I[<.
Run the engine at fast idle while making several
brake applications. Pull the brake pedal rear-
ward with approximately 44.5 N
(1 0 lbs) force.
Release the brake pedal and measure the
distance to the floor pan. Make a hard brake
application. Release the brake pedal and
measure the brake pedal to floor pan distance.
The brake pedal should return to its original
position.
Did the brake pedal return to its original posi-
tion?
+ Yes
Vehicle OK.
+ No
GO to L2.
I L2: CHECK FOR BRAKE PEDAL BINDING
1 171 Check the brake pedal for free operation.
I Is the brake pedal operating freely?
+ Yes
I INSTALL a new brake booster. REFER to:
(206-07 Power Brake Actuation)
Brake Booster
- LHD (Removal and lnstallation),
Brake Booster
- RHD (Removal and lnstallation).
TEST the system for normal operation.
+ No
REPAIR or INSTALL new brake pedal bush-
ings. REFER to: (206-06 Hydraulic Brake
Actuation)
Brake Pedal
- LHD, Vehicles With: Manual
Transaxle (Removal and lnstallation),
Brake Pedal
- LHD, Vehicles With: 4-Speed
Automatic Transmission
(AW81-40), Vehicles
With: Automated Gearshift (Removal and
Installation),
Brake Pedal
- RHD (Removal and lnstallation).
TEST the system for normal operation.
Component Tests It is possible that all evidence of fluid leakage may
have washed off if the vehicle has been operated
in rain or snow, as brake fluid is water-soluble.
Hydraulic Leak Check Refill the system, bleed then apply the brakes
several times. Examine the system to verify that
NOTE:Thet-e is a common clutch and brake fluid
the reservoir fluid level is actually dropping. Locate
reservoir, therefore it is possible that a clutch leak
can lead to reduction in the reservoir level.
-- --
2006.0 Fiesta 1212006 G28494en
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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.
2006.0 Fiesta 1212006
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206-00-32 Brake System - General Information 206-00-32
GENERAL PROCEDURES
Brake System Bleeding(l2 141 0) /'. ,
All Vehicles Repeat the procedure for the remaining brake
A WARNING:Brake fluid contains polyglycol lines.
ethers and polyglycols. Avoid contact with
General
Equipment
9m ACAUTION:M~~~ sure that the bleed nipple
the eyes. Wash hands thoroughly after
Vehicles with anti-lock brakes handling. If brake fluid contacts the eyes,
flush the eyes for
15 minutes with cold 10. N0TE:This step is only necessary when
running water. Get medical attention
if changing the brake fluid to remove the used
irritation persists.
If taken internally, drink brake
fluid from the hydraulic control unit
water and induce vomiting. Get medical (HCU).
Worldwide
Diagnostic System (WDS)
attention immediately. Failure to follow
Using WDS, bleed the brake system.
these instructions may result in personal'
injury.
CAUTI0N:If brake fluid is spilt on the
paintwork, the affected area must be
immediately washed down with cold water. cap
is installed after bleeding the brake
N0TE:Make sure that the vehicle is standing on a
level surface.
line(s). This will prevent corrosion to the
bleed nipple. Failure to follow this instruction
Bleeding may result in the bleed nipple becoming
seized.
N0TE:The system consists of separate circuits for
each front and diagonally opposite rear wheel.
Each circuit can be bled independently.
ACAUTION:T~~ brake fluid reservoir must
remain full with new, clean brake fluid at all
times during bleeding.
Install the bleed tube to the bleed nipple.
2. Immerse the end of the bleed tube in a bleed
jar containing a small quantity of approved
brake fluid.
3. Position the bleed jar base at least 300 mm
above the bleed nipple to maintain fluid
pressure and prevent air leaking past the
threads of the bleed nipple.
4. Loosen the bleed nipple by one-half turn.
5. Operate the brake pedal fully ipumping brake
fluid and air into the bleed jar) and allow the
brake pedal to return to the rest position.
6. Fill the brake fluid reservoir to the MAX mark.
7. Continue operating the brake pedal until
air-free fluid is being pumped into the bleed
jar.
8. With the brake pedal fully depressed tighten
the bleed nipple.
2006.0 Fiesta IZIZOO~ GI 7458en
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206-0516 Parking Brake and Actuation 206-05-6
DIAGNOSIS AND TESTING
TEST CONDITIONS
A2: CHECK FOR WORN BRAKE SHOES OR PADS
rn Inspect the brake shoes or pads for excessive
wear.
REFER to: Specifications (206-00, Specifica-
tions)
I Brake Shoes (206-02 Drum Brake, Removal
and Installation)
I Brake Pads (206-04, Removal and Installation).
Are the brake shoe linings or brake pads OK?
+ Yes
GO to A3.
+ No
INSTALL new brake shoes or pads.
REFER to: Brake Shoes (206-02 Drum Brake,
Removal and Installation)
I Brake Pads (206-04, Removal and Installa-
tion).
TEST the system for normal operation.
A3: CHECK FOR DAMAGED PARKING BRAKE CABLES
lnspect the parking brake cables and conduits
for damage, rust or fraying.
Are the parking brake cables and conduits OK?
+ Yes
CHECK for other causes such as loose
parking brake control or conventional brake
system components.
+ No
REPAIR or INSTALL cables and conduit as
necessary. TEST the system for normal
operation.
2006.0 Fiesta 1212006 GI 7495en
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206-05-7 Parking Brake and Actuation 206-05-7
DIAGNOSIS AND TESTING
B1: CHECK PARKING BRAKE CONTROL
rn Raise and support the vehicle on a lift with the
parking brake fully applied.
REFER to: Lifting
(1 00-02, Description and
Operation).
- With the aid of another technician, release the
parking brake and check the operation of the
brake cables and levers.
Did the parking brake release?
+ Yes
CHECK the other causes such as conven-
tional brake system components. REPAIR or
INSTALL new components as necessary.
+ No
GO to B2.
B2: CHECK PARKING BRAKE CABLES
rn Loosen the parking brake cable tension.
- Rotate the rear wheels by hand.
Did the rear wheels turn freely?
+ Yes
INSTALL a new parking brake control.
REFER to: Parking Brake Control (206-05,
Removal and Installation).
TEST the system for normal operation.
+ No
GO to
83.
B3: CHECK FRONT PARKING BRAKE CABLE
Disconnect the parking brake front cable and
conduit from the rear brake cable and conduit
at the equalizer.
- Rotate the rear wheels by hand.
Did the rear wheels turn freely?
+ Yes
INSTALL a new front parking brake cable and
conduit.
REFER to: Parking Brake Cable (206-05,
Removal and Installation).
TEST the system for normal operation.
+ No
GO to
B4.
i
2006.0 Fiesta 1212006 GI 7495en
PINPOINT TEST B : THE PARKING BRAKE WILL NOT RELEASE
TEST CONDITIONS
DETAl LSIRESU LTSIACTIONS
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