vacuum FORD MUSTANG 2003 Workshop Manual

The equal distribution of weight on each side of the centerline, so that when the wheel and tire
assembly spins, there is no tendency for the assembly to move from side-
to-side (wobble).
Dynamically unbalanced wheel and tire assemblies can cause wheel shimmy.
Engine Imbalance
A condition in which an engine's center mass is not concentric to the rotation center, causing
excessive motion.
Engine Misfire
When combustion in one or more cylinders does not occur or occurs at the wrong time.
Engine Shake
An exaggerated engine movement or vibration that directly increases in frequency as the engine speed
increases. It is caused by non- equal distribution of mass in the rotating or reciprocating components.
Flexible Coupling
A flexible joint.
Float
A drive mode on the dividing line between cruise and coast where the throttle setting matches the
engine speed with the road speed.
Flutter
Mid to high (100- 2000 Hz) intermittent sound due to air flow. Similar to a flag flapping in the wind.
Frequency
The rate at which a cycle occurs within a given time.
Gravelly Feel
A grinding or growl in a component, similar to the feel experienced when driving on gravel.
Grind
An abrasive sound, similar to using a grinding wheel, or rubbing sand paper against wood.
Hiss
Steady high frequency (200- 800 Hz) noise. Vacuum leak sound.
Hoot
A steady low frequency tone (50- 500 Hz), sounds like blowing over a long neck bottle. Howl Klj . 6 ba
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„
Frequencies have a range of plus or minus 2. A reading of 10 Hz can be displayed as an
8 Hz through 12 Hz.
d. Place the vibration sensor on or near the suspect area outside the vehicle.
e. Continue the road test, driving the vehicle at the speed the symptom occurs, and take another reading.
f. Compare the readings.
„A match in frequency indicates the problem component or area.
„ An unmatched test could indicate the concern is caused by the engine, torque converter,
or engine accessory. Use the EVA in the rpm mode and check if concern is rpm related.
„ Example: A vibration is felt in the seat. Place the sensor on the console. Record the
readings. Place the vibration sensor on the rear axle. Compare the readings. If the
frequencies are the same, the axle is the problem component.
Vibrate Software®
Vibrate Software® ( Rotunda tool number 215- 00003) is a diagnostic aid which will assist in pinpointing
the source of unacceptable vibrations. The engine's crankshaft is the point of reference for vibration
diagnosis. Every rotating component will have an angular velocity that is faster, slower, or the same as
the engine's crankshaft. Vibrate Software® calculates the angular velocity of each component and
graphically represents these velocities on a computer screen and on a printed vibration worksheet.
The following steps outline how Vibrate Software® helps diagnose a vibration concern:
zEnter the vehicle information. Vibrate will do all the calculations and display a graph showing
tire, driveshaft and engine vibrations.
z Print a Vibration Worksheet graph. The printed graph is to be used during the road test.
z Road test the vehicle at the speed where the vibration is most noticeable. Record the vibration
frequency (rpm) and the engine rpm on the worksheet graph. The point on the graph where the
vibration frequency (rpm) reading and the engine rpm reading intersect indicates the specific
component group causing the concern.
„An EVA or equivalent tool capable of measuring vibration frequency and engine rpm will
be needed.
z Provide pictures of diagnostic procedures to aid in testing components.
Combination EngineEAR/ChassisEAR
An electronic listening device used to quickly identify noise and the location under the chassis while
the vehicle is being road tested. The ChassisEARs can identify the noise and location of
damaged/worn wheel bearings, CV joints, brakes, springs, axle bearings or driveshaft carrier bearings.
EngineEAR Basic Unit
An electronic listening device used to detect even the faintest noises. The EngineEARs can detect the
noise of damaged/worn bearings in generators, water pumps, A/C compressors and power steering
pumps. They are also used to identify noisy lifters, exhaust manifold leaks, chipped gear teeth and for
detecting wind noise. The EngineEAR has a sensing tip, amplifier, and headphones. The directional
sensing tip is used to listen to the various components. Point the sensing tip at the suspect component
and adjust the volume with the amplifier. Placing the tip in direct contact with a component will reveal
structure-borne noise and vibrations, generated by or passing through, the component. Various
volume levels can reveal different sounds.
Ultrasonic Leak Detector
The Ultrasonic Leak Detector is used to detect wind noises caused by leaks and gaps in areas where
there is weather- stripping or other sealing material. It is also used to identify A/C leaks, vacuum leaks Klj . 12 ba
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noise—
normally
accompanied by
vibration Powertrain/Drivetrain Mount Neutralizing in this
section.
z Damaged or
misaligned exhaust
system. z
INSPECT the exhaust
system for loose or broken
clamps and brackets.
CARRY OUT Exhaust System Neutralizing in this
section.
z Whistling noise—
normally
accompanied
with poor idle
condition z
Air intake system. zCHECK the air intake
ducts, air cleaner, throttle
body and vacuum hoses for
leaks and correct fit.
REPAIR or ADJUST as
necessary. REFER to
Section 303 - 12
z
Clunking noise zWater pump has
excessive end play or
imbalance. z
CHECK the water pump for
excessive end play.
INSPECT the water pump
with the drive belt off for
imbalance. INSTALL a new
water pump as necessary.
REFER to Section 303 -
03A .
z Generator has
excessive end play. z
CHECK the generator for
excessive end play.
REPAIR or INSTALL a new
generator. REFER to
Section 414 - 02 .
z Pinging noise zExhaust system leak. zINSPECT the exhaust
system for leaks. REPAIR
as necessary.
z Gasoline octane too
low. z
VERIFY with customer the
type of gasoline used.
CORRECT as necessary.
z Knock sensor
operation. z
CHECK the knock sensor.
INSTALL a new knock
sensor as necessary.
REFER to Section 303 - 14 .
z Incorrect spark
timing. z
CHECK the spark timing.
REPAIR as necessary.
z High operating
temperature. z
INSPECT cooling system
for leaks. CHECK the
coolant level. REFILL as
necessary. CHECK the
coolant for the correct mix
ratio. DRAIN and REFILL
as needed. CHECK engine
operating temperature is
within specifications.
REPAIR as necessary.
z Foul- out spark plug. zCHECK the spark plugs.
REPAIR or INSTALL new
spark plugs as necessary.
z Catalytic converter. zAcceptable noise.
z Knocking noise—
light knocking
noise, also z
Excessive clearance
between the piston
and the cylinder wall. z
Engine cold and at high
idle. Using an EngineEAR,
pull a spark plug or fuel Klj . 24 ba
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(+40°F) or colder at
first start of the day
between ball
bearings and
bearing race.
z Power steering moan
— occurs at high idle
and possibly at idle
during the first cold
start of the day in
temperatures of
approximately - 18°C
(0°F) or colder. Noise
can even be a severe
screech for less than
one minute in very
cold temperatures of
approximately - 29°C
(- 20°F) or colder z
High fluid
viscosity, or
plugged
reservoir screen
in power
steering
reservoir
starves pump
causing
cavitation. z
Go To Pinpoint Test D .
z Generator whine —
during high electrical
loads at idle or high
idle, a high pitch
whine or moan is
emitted from the
generator z
Generator
electrical field
noise. z
Using an EngineEAR,
PROBE near the generator
housing. LISTEN for
changes in the noise level
while changing electrical
loads (such as rear defrost,
headlamps, etc.). CARRY
OUT a generator load test. If
the system passes the load
test, the noise is from the
generator bearings,
INSTALL new bearings. If
the system fails the load
test, INSTALL a new
generator. REFER to
Section 414 - 02 .
z Engine- driven cooling
fan moan — occurs
during the first start of
the day. It is most
objectionable near
idle speeds up to
2000 rpm. The noise
increases with rpm z
The viscous
cooling fan
clutch engages
until the fluid in
the clutch
reaches normal
operating
temperature,
causing the fan
to fully engage. z
Go To Pinpoint Test E .
z Drumming noise —
occurs inside the
vehicle during idle or
high idle, hot or cold.
Very low- frequency
drumming is very rpm
dependent z
Exhaust system
vibration excites
the body
resonances
inducing interior
noise.
z Engine vibration
excites the
body
resonances
inducing interior
noise. z
Go To Pinpoint Test F .
z Hissing noise —
occurs during idle or
high idle that is
apparent with the
hood open z
Vacuum leak or
idle air control
(IAC) valve flow
noise. z
Use the Ultrasonic Leak
Detector/EngineEAR to
locate the source. Scan the
air intake system from the
inlet to each cylinder intake Klj . 29 ba
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port. DISCARD the leaking
parts, and INSTALL a new
component.
z Vehicles with a
plastic intake
manifold. z
Acceptable condition. Some
plastic manifolds exhibit this
noise, which is the effect of
the plastic manifold.
z Automatic
transmission buzz or
hiss z
Incorrect
driveline
angles. z
CHECK for correct driveline
angles. REPAIR as
necessary. REFER to
Section 205 - 00 .
z Worn or
damaged main
control
solenoids or
valves. z
Using a transmission tester,
activate the solenoids to
duplicate sound. INSTALL
new components as
necessary. REFER to
Section 307 - 01 .
z Manual Transmission
Clutch throw- out
bearing whine. A
change in noise pitch
or loudness while
depressing the clutch
pedal z
Worn throw- out
bearing. z
INSTALL a new throw- out
bearing. REFER to Section 308 - 01 .
z Heating, vacuum and
air conditioning
(HVAC) system chirp
— most audible inside
the vehicle. Listen for
a change in noise
pitch or loudness
while changing the
HVAC system blower
speed z
Damaged or
worn HVAC
blower bearing. z
INSTALL a new blower
motor. REFER to Section 412 - 02 .
z Air conditioning (A/C)
clutch ticking —
occurs when the
compressor clutch
engages z
Acceptable
noise.
z Incorrect air
gap. z
LISTEN to the clutch to
determine if the noise occurs
with clutch engagement. A
small amount of noise is
acceptable. If the noise is
excessive, CHECK the A/C
clutch air gap. INSPECT the
A/C clutch for wear or
damage. INSTALL a new
clutch as necessary. REFER
to Section 412 - 03 .
z Intermittent rattle, or
scraping/rubbing
noise z
Loose exhaust
heat shield(s). z
INSPECT the exhaust
system for loose parts using
a glove or clamps to verify
cause. REPAIR as
necessary. REFER to
Section 309 - 00 .
z Wiring, hose or
other part
interfering with
accessory drive
belt or pulley. z
INSPECT accessory drive
system closely verifying
there is adequate clearance
to all rotating components.
REPAIR as necessary.
z Engine ticking or
knocking noise —
occurs during idle or z
Piston noise or
valvetrain noise
(bled down z
Go To Pinpoint Test G . Klj . 30 ba
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The vehicle is equipped with a vacuum-
assisted or a hydro-boost power braking system. Refer to
Section 206 - 07 .
The braking system is a front- to-rear split hydraulic system. Refer to Section 206 - 06 .
The front wheel brakes utilize a dual piston brake caliper and disc brake system. Refer to Section 206 -
03 .
The rear brakes utilize a single piston brake caliper and disc brake system. Refer to Section 206 - 04 .
The parking brake system is a mechanical system that is controlled by an independent hand- operated
parking brake control and is self- adjusting. Refer to Section 206 - 05 .
A 4- wheel anti- lock brake system or anti-lock brake system with traction control (4WABS) is optional
equipment on all models except Cobra. Cobra has ABS and traction control as standard equipment.
Refer to Section 206 - 09A . hydraulic control unit and control module assy (non-
traction)
1 2C353 Four wheel anti-
lock brake system (4WABS)
hydraulic control unit and control module assy
(traction) 2 2B559 Hydro-Boost brake booster and brake master
cylinder assy 3 2B195 Vacuum brake booster and brake master cylinder
assy
4 2K327 Rear disc brake assy
5 2780 Parking brake control
6 2B119 Front disc brake assy Klj . 2 ba
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in the brake master cylinder reservoir are also indicators of system concerns.
If a wheel is locked and the vehicle must be moved, open a bleeder screw at the locked wheel (1007)
to let out enough fluid to relieve the pressure. Close the bleeder screw. This bleeding operation may
release the brakes but will not correct the cause of trouble. If this does not relieve the locked wheel
condition, repair the locked components before proceeding.
Inspect all hoses and connections. All unused vacuum connectors should be capped. Make sure
hoses and their connections are correctly secured and in good condition with no holes, soft or
collapsed areas.
Non-
Pressure Leaks
The only part of the brake system that could have a brake fluid loss that does not appear when the
system is under pressure is the brake master cylinder reservoir area. Brake fluid loss can be caused
by a missing or poorly- fitted brake master cylinder filler cap (2162), a punctured or otherwise damaged
brake master cylinder reservoir, a missing or damaged brake master cylinder filler cap gasket, or by
missing, damaged or poorly- fitted sealing grommets between the brake master cylinder (2140) and the
brake master cylinder reservoir.
The brake master cylinder reservoir grommets are not separately serviceable and must be installed
new as part of a new brake master cylinder reservoir.
Install a new flexible brake hose if it shows signs of softening, cracking or other damage.
When installing a new brake hose, position the hose to avoid contact with other vehicle components.
Road Test
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.
The driver should have a thorough knowledge of brake system operation and accepted general
performance guidelines in order to make good comparisons and detect performance problems.
Select a road that is reasonably smooth and level. Gravel or bumpy roads are not suitable because the
surface does not allow the tires to grip the road equally. Avoid crowned roads.
A key factor in evaluating brake concerns is the deceleration rate. This varies from vehicle to vehicle
and with changes in operating conditions. It is evident how well the brakes are working after just a few
applications.
Avoid locking the brakes. Locked brakes are not an indication of braking efficiency.
Visual Inspection Chart Mechanical Electrical
z
Brake master cylinder
z Brake caliper piston
z Brake discs
z Brake pads z
Parking brake switch
z Damaged or corroded wiring harness
z Brake master cylinder fluid level switch Klj . 2 ba
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For low or spongy brake pedal concerns:
zcheck and, if necessary, refill the brake master cylinder reservoir.
z bleed the brake system and retest the brake pedal feel.
z if the brake pedal is still low or feels spongy, check the brake pedal mounting for looseness and
correct installation. Check the power brake booster and the brake master cylinder for loose
mounting. Correct as necessary and retest the system for normal operation.
For a slow or incomplete brake pedal return concern:
zinspect for binding, damage, correct installation or interference at the brake pedal.
z check the power brake booster for binding, damage and correct installation.
Vibration When Brakes are Applied
For vibration concerns when brakes are applied, perform the following procedure.
Visually inspect: ztire condition and pressure.
z suspension bushings and ball joints.
Correct as necessary. 1. Verify and isolate the concern. Brake roughness can be felt in: zthe steering wheel.
z the seat.
z the brake pedal.
2. After verifying the concern, check for related concerns in the: zOn- Line Automotive Service Information System (OASIS).
z Technical Service Bulletins.
3. Check wheel bearing end- play and correct as necessary.
4. NOTE: Begin at the front of the vehicle unless the vibration has been isolated to the rear.
Remove the tire and wheel.
5. Remove the brake caliper.
6. Measure and record the brake disc thickness. Install a new brake disc if the thickness after machining will be at or below specification. The specification is molded into the brake disc. Do z
Power brake booster
z Brake pedal linkage
z Vacuum booster hose
z Tires
z Foreign material Klj . 3 ba
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Component Tests
Brake Booster
1. Check the hydraulic brake system for leaks or insufficient fluid.
2. With the transmission (7003) in NEUTRAL, stop the engine (6007) and apply the parking brake control (2780). Apply the brake pedal several times to exhaust all vacuum in the system.
3. Apply the brake pedal and hold it in the applied position. 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 power brake booster system is not functioning. Continue with the following
steps.
4. Remove the vacuum booster hose from the check valve connection. Manifold vacuum must be available at the check valve end of the vacuum booster hose with the engine at idle speed and
the transmission in NEUTRAL. If the manifold vacuum is available to the power brake booster,
connect the vacuum booster hose to the power brake booster check valve and repeat Steps 2
and 3.
5. If no downward movement of the brake pedal is felt, install a new power brake booster.
6. 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) of force. The
brake pedal feel should be the same as that noted with the engine operating. If the brake pedal
feels hard (no power assist), install a new power brake booster check valve and retest. If the
brake pedal feels spongy, bleed the hydraulic system to remove air. For additional information,
refer to Bleeding — System in this section. Check Valve z
Engine running at idle speed.
z CAUTION: Do not hold the brake pedal at 444 Nm
(100 lb) force for more than 5 seconds at a time.
z Apply brake pedal with approximately 444 Nm (100 lb)
force and hold.
z Check hydro-boost unit input seal, housing seal,
accumulator seal, piston seal and spool plug seal for
leakage.
z Is hydro- boost unit free of leaks? Yes
GO to
G6 .
No
INSTALL a new hydro- boost
unit. G6 CHECK RESERVE RETENTION
z
Engine running at idle speed.
z CAUTION: Do not hold the brake pedal at 444 Nm
(100 lb) force for more than 5 seconds at a time.
z Charge system to pressure by holding the steering wheel at
stop or by pressing the brake pedal with approximately 444
Nm (100 lb) force.
z Key in OFF position.
z Wait five seconds.
z Press brake pedal and observe if there is any power brake
reserve.
z Is there any power brake reserve? Yes
Hydro-
boost unit is OK.
No
INSTALL a new hydro- boost
unit. Klj . 13 ba
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The function of the power brake booster check valve is to allow manifold vacuum to enter the power
brake booster and prevent the escape of vacuum in case manifold vacuum is lost during sustained full
throttle operation.
To test the function of the power brake booster check valve :
zStart and run the engine for at least 10 seconds.
z Operate the brake pedal to check for power assist.
z Disconnect the vacuum booster hose from the power brake booster check valve. Do not remove
the power brake booster check valve from the power brake booster.
z There should be enough vacuum retained in the brake booster for at least one more power-
assisted brake operation.
Brake Master Cylinder — Normal Conditions
The following conditions are considered normal and are not indications that the brake master cylinder
is in need of service.
Condition 1: During normal operation of the brake master cylinder, the fluid level in the brake master
cylinder reservoir will rise during brake application and fall during release. The net fluid level (i.e., after
brake application and release) will remain unchanged.
Condition 2: A trace of brake fluid will exist on the booster shell below the master cylinder mounting
flange. This results from the normal lubricating action of the master cylinder bore and seal.
Condition 3: Fluid level will decrease with pad wear.
Brake Master Cylinder — Abnormal Conditions
Changes in brake pedal feel or travel are indicators that something could be wrong in the brake
system. GO to Symptom Chart for abnormal condition diagnosis.
Bypass Condition Test 1. Disconnect the brake lines at the brake master cylinder.
2. Plug the outlet ports of the brake master cylinder.
3. Apply the brakes. If brake pedal height cannot be maintained, the brake master cylinder has an internal leak and must be rebuilt or replaced.
Compensator Port Check
The purpose of the compensator ports in the brake master cylinder is to supply any additional brake
fluid required by the system due to brake pad wear and to allow brake fluid returning from the brake
lines to the brake master cylinder to enter the brake master cylinder reservoir.
The returning brake fluid will cause a slight turbulence in the brake master cylinder reservoir. Klj . 14 ba
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