204-04-3 Wheels and Tires 204-04-3
DIAGNOSIS AND TESTING
Wheels and Tires
lnspection and Verification
Visual Inspection Chart
I Mechanical I
I Tire pressure(s) * I
I Wheel nuts I
I Wheel studs I
* Vehicles equipped with a tire pressure monitoring system must be inspected for correct operation
using the diagnostic tool.
To maximize tire performance, inspect the tires for
signs of incorrect inflation and uneven wear which
may indicate a need for balancing, rotation or
suspension alignment. Tires should also be
checked frequently for cuts, stone bruises,
abrasions, blisters and for objects that may have
become embedded in the tread. More frequent
inspections are recommended when rapid or ( extreme temperature changes occur or when road
surfaces are rough or occasionally littered with
foreign material.
As a further visible check of tire condition, tread
wear indicators are molded into the bottom of the
tread grooves. When these indicator bands become
visible, new tires must be installed.
Tire Wear Diagnosis
Uneven wear is usually caused by either excessive
camber or excessive toe on tires.
Sometimes incorrect toe settings or worn struts will
cause severe 'cupping' or 'scalloped' tire wear on
non-driven wheels.
Severely incorrect toe settings will also cause other unusual wear patterns.
Tire Vibration Diagnosis
A tire vibration diagnostic procedure always begins
with a road test. The road test and customer
interview (if available) will provide much of the
information needed to find the source of a vibration. During
the road test, drive the vehicle on a road
that is smooth and free of undulations. If vibration
is apparent, note and record the following:
- the speed at which the vibration occurs.
- what type of vibration occurs in each speed
range.
- mechanical or audible
- how the vibration is affected by changes in the
following:
- engine torque
- vehicle speed
- engine speed
- type of vibration - sensitivity:
- torque sensitive
- vehicle speed sensitive
- engine speed sensitive
The following explanations help isolate the source
of the vibration.
Torque Sensitive
This means that the condition can be improved or
made worse by accelerating, decelerating,
coasting, maintaining a steady vehicle speed or
applying engine torque.
Vehicle Speed Sensitive
This means that the vibration always occurs at the
same vehicle speed and is not affected by engine
torque, engine speed or the transmission gear
selected.
2006.0 Fiesta 1212006
procarmanuals.com
204-0414 Wheels and Tires 204-04-4
DIAGNOSIS AND TESTING
Engine Speed Sensitive A thumping noise usually means that the tire is flat
or has soft spots making a noise as they slap the
This means that the vibration occurs at varying
roadway. Tire whine can be distinguished from axle
vehicle speeds when a different transmission gear
noise. Tire whine remains the same over a range
is selected. It can sometimes be isolated by
of speeds.
increasing Or decreasing engine with the A complete road test procedure is described in transmission in NEUTRAL or by stall testing with Section the transmission in gear. If the condition is engine
speed sensitive, the-cause is probably not related
REFER to: Noise, Vibration and Harshness (NVH)
to the tires. (1
00-04 Noise, Vibration and Harshness,
If the road test indicates that there is tire whine, Diagnosis and
Testing).
but no shake or vibration, the noise originates with
the contact between the tire and the road surface.
Symptom Chart
Symptom Possible Sources Action
Tire(s) show excess wear on
edge of tread
I Vehicle overloaded. I CORRECT as necessary. I
Tire(s) under-inflated.
lncorrect wheel alignment. ADJUST the tire pressure(s).
ADJUST the wheel alignment.
REFER to: (204-00 Suspension
System
- General Information)
Specifications (Specifications), Front Toe Adjustment (General
Procedures).
Tire(s) show excess wear in Tire(s) over-inflated.
I I
ADJUST the tire pressure(s).
I center of tread
Other excessive tire wear Incorrect tire pressure(s).
concerns
need rotating.
ADJUST the tire pressure(s).
ROTATE the wheel and tire
assemblies.
lncorrect wheel alignment. ADJUST the wheel alignment.
REFER to: (204-00 Suspension
System
- General Information)
Specifications (Specifications), Front Toe Adjustment (General
Procedures).
I Vehicle overloaded.
Loose or leaking front strut and
spring assembly. CORRECT as necessary.
I
2006.0 Fiesta 1212006 G25362en
TIGHTEN
or INSTALL new
suspension components as
necessary.
REFER to: Shock Absorber
and Spring Assembly (204-01
,
Front Suspension, Removal
and Installation).
procarmanuals.com
206-004 Brake System - General Information 206-00-4
DIAGNOSIS AND TESTING
Symptom Chart - -
Symptom
Brakes pull or drift
Possible Sources Action
Worn or damaged brake shoes
or brake pads and linings. 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).
Abnormal wear or distortion of
brake discs.
INSTALL a new brake discs.
REFER to: Brake Disc (206-04
Rear Disc Brake, Removal
and Installation).
lncorrect rear brake adjust-
ment. PERFORM
a parking brake
cable adjustment. REFER to:
(206-05 Parking Brake and
Actuation)
Parking Brake Cable Adjust-
ment
- Vehicles With: Rear
Drum Brakes (General
Procedures),
Parking Brake Cable Adjust-
ment
- Vehicles With: Rear
Disc Brakes (General
Procedures).
lncorrect wheel alignment
adjustment. PERFORM a
wheel alignment
adjustment.
REFER to: Front Toe Adjust-
ment (204-00 Suspension
System
- General Informa-
tion, General Procedures).
l ncorrect wheel bearing preload
adjustment. ADJUST or INSTALL a new
wheel bearing. REFER to:
Front Wheel Bearing (204-01 Front Suspension, Removal
and Installation),
Rear Wheel Bearing (204-02 Rear Suspension, Removal
and Installation).
2006.0 Fiesta 1212006 G28494en
Unequal air pressure in the
tires. INFLATE the tires to the correct
pressure.
procarmanuals.com
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
procarmanuals.com
206-00-1 0 Brake System - General Information 206-00-1 0
DIAGNOSIS AND TESTING
Pinpoint Tests
PINPOINT TEST A : BRAKES PULL OR DRIFT
TEST CONDITIONS
DETAILSIRESU LTSIACTIONS
A1 : ROAD TEST THE VEHICLE
Road test the vehicle and apply the brake pedal.
Does the vehicle pull or drift?
+ Yes
GO to A2.
+ No
Vehicle OK.
A2: TIRE INSPECTION
Check for excessive wear or incorrect tire pres-
sures.
Are the tires in good condition?
-, Yes
GO to A3.
+ No
INFLATE the tires to the correct pressure.
INSTALL new tires if excessively worn. TEST
the system for normal operation.
A3: BRAKE SHOE OR BRAKE PADS AND LINING INSPECTION
Inspect the brake shoes or brake pads for
grease or fluid on the linings and or wear
concerns.
Are any concerns present?
+ Yes
INSTALL new brake shoes or brake pads.
REFER to:
Brake Shoes (206-02 Drum Brake, Removal and
Installation),
Brake Pads (206-03 Front Disc Brake, Removal
and Installation),
Brake Pads (206-04 Rear Disc Brake, Removal
and Installation).
TEST the system for normal operation.
+ No
GO to A4.
2006.0 Fiesta 1212006 G28494en
procarmanuals.com
206-00-21 Brake System - General Information 206-00-21
DIAGNOSIS AND TESTING
TEST CONDITIONS DETAILSIRESU LTSIACTIONS
162: TIRE INSPECTION
rn Check for excessive tire wear or incorrect tire
pressures.
Are the tires in good order?
-+ Yes
GO to G3. GO to Pinpoint Test G.
-+ No
SUBSTITUTE known good tires. INFLATE to
the correct pressure. TEST the system for
normal operation.
163: BRAKE SHOES OR BRAKE PADS INSPECTION I
rn Inspect the brake shoes or brake pads are
correctly fitted and for grease or fluid contamin-
ation or wear concerns.
Are there any concerns?
-+ Yes
REPAIR or INSTALL new components as
necessary. TEST the system for normal
operation.
-+ No
GO to G4. GO to Pinpoint Test G.
1 64: CHECK PRESSURE CONSCIOUS REDUCING VALVE-RIGHT-HAND REAR I
rn Install pressure gauges in the left-hand front
and right-hand rear bleed nipples. Apply the brake to read 6895
kPa (1 000 psi) at the left-
hand front wheel.
- Read the pressure at the right-hand rear
wheel.
Does the pressure gauge read between 4692-
5164
kPa (680-750 psi) at the right-hand rear
wheel?
-+ Yes
TEST the brake booster. Go to Pinpoint Test
I.
-+ No
INSTALL a new right-hand rear brake pres-
sure control valve. 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 normal operation.
2006.0 Fiesta 12/2006 G28494en
procarmanuals.com