wheel FORD MUSTANG 2003 User Guide

starting point.
Decibel
A unit of measurement, referring to sound pressure level, abbreviated dB.
Drive Engine Run-
Up (DERU) Test
The operation of the engine through the normal rpm range with the vehicle standing still, the brakes
applied and the transmission engaged. This test is used for noise and vibration checks.
Driveline Angles
The differences of alignment between the transmission output shaft, the driveshaft, and the rear axle
pinion centerline.
Driveshaft
The shaft that transmits power to the rear axle input shaft (pinion shaft). In a two- piece driveshaft, it is
the rearmost shaft.
Drivetrain
All power transmitting components from the engine to the wheels; includes the clutch or torque
converter, the transmission, the transfer case, the driveshaft, and the front or rear drive axle.
Drivetrain Damper
A weight attached to the engine, the transmission, the transfer case, or the axle. It is tuned by weight
and placement to absorb vibration.
Drone
A low frequency (100- 200 Hz) steady sound, like a freezer compressor. Also described as a moan.
Drumming
A cycling, low-frequency (20- 100 Hz), rhythmic noise often accompanied by a sensation of pressure on
the ear drums. Also described as a low rumble, boom, or rolling thunder. Dynamic Balance Klj . 5 ba
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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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Lateral runout means measuring the movement or "wobble" of a wheel or tire at the sidewall. Radial
runout means measuring the out-of-
round at the tread surface.
Rustling
Intermittent sound of varying frequency (100- 2000 Hz), sounds similar to shuffling through leaves.
Shake
A low- frequency vibration (5-20 Hz), usually with visible component movement. Usually relates to tires,
wheels, brake drums or brake discs if it is vehicle speed sensitive, or engine if it is engine speed
sensitive. Also referred to as a shimmy or wobble.
Shimmy
An abnormal vibration or wobbling, felt as a side- to-side motion of the steering wheel in the driveshaft
rotation. Also described as waddle.
Shudder
A low- frequency vibration that is felt through the steering wheel or seat during light brake application.
Slap
A resonance from flat surfaces, such as safety belt webbing or door trim panels.
Slip Yoke/Slip Spline
The driveshaft coupling that allows length changes to occur while the suspension articulates and while
the driveshaft rotates.
Squeak
A high- pitched transient sound, similar to rubbing fingers against a clean window.
Squeal
A long- duration, high- pitched noise.
Static Balance
The equal distribution of weight around the wheel. Statically unbalanced wheel and tire assemblies can
cause a bouncing action called wheel tramp. This condition will eventually cause uneven tire wear.
Tap
A light, rhythmic, or intermittent hammering sound, similar to tapping a pencil on a table edge.
Thump
A dull beat caused by two items striking together. Tick Klj . 9 ba
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A rhythmic tap, similar to a clock noise.
Tip-
In Moan
A light moaning noise heard during light vehicle acceleration, usually between 40- 100 km/h (25-65
mph).
TIR
The acronym for total indicated runout is TIR.
Tire Deflection
The change in tire diameter in the area where the tire contacts the ground.
Tire Flat Spots
A condition commonly caused by letting the vehicle stand while the tires cool off. This condition can be
corrected by driving the vehicle until the tires are warm. Also, irregular tire wear patterns in the tire
tread resulting from wheel- locked skids.
Tire Force Vibration
A tire vibration caused by variations in the construction of the tire that is noticeable when the tire
rotates against the pavement. This condition can be present on perfectly round tires because of
variations in the inner tire construction. This condition can occur at wheel rotation frequency or twice
rotation frequency.
Transient
A noise or vibration that is momentary, a short duration.
Two- Plane Balance
Radial and lateral balance.
Vibration
Any motion, shaking or trembling, that can be felt or seen when an object moves back and forth or up
and down.
Whine
A constant, high- pitched noise. Also described as a screech.
Whistle
High- pitched noise (above 500 Hz) with a very narrow frequency band. Examples of whistle noises are
a turbocharger or airflow around an antenna.
Wind Noise
Any noise caused by air movement in, out or around the vehicle. Klj . 10 ba
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WOT
The acronym for wide open throttle is WOT.
Tools and Techniques
Electronic Vibration Analyzer (EVA)
The EVA is a hand-
held electronic diagnostic tool which will assist in locating the source of
unacceptable vibrations. The vibration sensor can be remotely mounted anywhere in the vehicle for
testing purposes. The unit displays the three most common vibration frequencies and their
corresponding amplitudes simultaneously. A bar graph provides a visual reference of the relative
signal strength (amplitude) of each vibration being displayed and its relative G force. The keypad is
arranged to make the EVA simple to program and use. Some of the functions include the ability to
average readings as well as record, play back and freeze readings. The EVA has a strobe balancing
function that can be used to detect imbalance on rotating components such as a driveshaft or engine
accessories.
The EVA allows for a systematic collection of information that is necessary to accurately diagnose and
repair NVH problems. For the best results, carry out the test as follows:
a. Test drive the vehicle with the vibration sensor inside the vehicle.
b. Place the sensor in the vehicle according to feel. „If the condition is felt through the steering wheel, the source is most likely in the front of
the vehicle.
„ A vibration that is felt in the seat or floor only will most likely be found in the driveline,
drive axle or rear wheels and tires.
c. Record the readings. Also note when the condition begins, when it reaches maximum intensity, and if it tends to diminish above/below a certain speed.
„Frequencies should be read in the "average" mode. Item Description
1 EVA screen
2 Frequency mode displayed in rpm or Hz
3 Active sensor input (A or B)
4 Current active mode
5 G force indicators or the strongest frequencies in descending strength of each vibration
6 Strength of each vibration
7 Frequency in rpm/Hz of each vibration Klj . 11 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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NOTE:
It may be necessary to have the customer ride along or drive the vehicle to point out the
concern. During the road test, take into consideration the customer's driving habits and the driving
conditions. The customer's concern just may be an acceptable operating condition for that vehicle.
The following is a brief overview of each test in the order in which it appears. A review of this
information helps to quickly identify the most appropriate process necessary to make a successful
diagnosis. After reviewing this information, select and carry out the appropriate test(s), proceeding to
the next step of this process.
zThe Slow Acceleration Test is normally the first test to carry out when identifying an NVH
concern, especially when a road test with the customer is not possible.
z The Heavy Acceleration Test helps to determine if the concern is torque- related.
z The Neutral Coast Down Speed Test helps to determine if the concern is vehicle speed- related.
z The Downshift Speed Test helps to determine if the concern is engine speed- related.
z The Steering Input Test helps to determine how the wheel bearings and other suspension
components contribute to a vehicle speed- related concern.
z The Brake Test helps to identify vibrations or noise that are brake related.
z The Road Test Over Bumps helps isolate a noise that occurs when driving over a rough or
bumpy surface.
z The Engine Run- Up Tests consist of the Neutral Run- Up Test and the Engine Load Test. These
tests help to determine if the concern is engine speed- related.
z The Neutral Run- Up Test is used as a follow- up test to the Downshift Speed Test when the
concern occurs at idle.
z The Engine Load Test helps to identify vibration/noise sensitive to engine load or torque. It also
helps to reproduce engine speed- related concerns that cannot be duplicated when carrying out
the Neutral Run- Up Test or the Neutral Coast Down Test.
z The Engine Accessory Test helps to locate faulty belts and accessories that cause engine
speed- related concerns.
z The Vehicle Cold Soak Procedure helps to identify concerns occurring during initial start- up and
when an extended time lapse occurs between vehicle usage.
Slow Acceleration Test
To carry out this test, proceed as follows:
zSlowly accelerate to the speed where the reported concern occurs. Note the vehicle speed, the
engine rpm and, if possible, determine the vibration frequency.
z Attempt to identify from what part of the vehicle the concern is coming.
z Attempt to identify the source of the concern.
z Proceed as necessary.
Heavy Acceleration Test
To carry out this test, proceed as follows:
zAccelerate hard from 0- 64 km/h (0-40 mph).
z Decelerate in a lower gear.
z The concern is torque related if duplicated while carrying out this test.
z Proceed as necessary. Klj . 6 ba
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Neutral Coast Down Speed Test
To carry out this test, proceed as follows:
zDrive at a higher rate of speed than where the concern occurred when carrying out the Slow
Acceleration Test.
z Place the transmission in NEUTRAL and coast down past the speed where the concern occurs.
z The concern is vehicle speed- related if duplicated while carrying out this test. This eliminates
the engine and the torque converter as sources.
z If the concern was not duplicated while carrying out this test, carry out the Downshift Speed
Test to verify if the concern is engine speed related.
z Proceed as necessary.
Downshift Speed Test
To carry out this test, proceed as follows:
zShift into a lower gear than the gear used when carrying out the Slow Acceleration Test.
z Drive at the engine rpm where the concern occurs.
z The concern is engine speed related if duplicated while carrying out this test. This eliminates the
tires, wheels, brakes and the suspension components as sources.
z If necessary, repeat this test using other gears and NEUTRAL to verify the results.
z Proceed as necessary.
Steering Input Test
To carry out this test, proceed as follows:
zDrive at the speed where the concern occurs, while making sweeping turns in both directions.
z If the concern goes away or gets worse, the wheel bearings, hubs, U- joints (contained in the
axles of 4WD applications), and tire tread wear are all possible sources.
z Proceed as necessary.
Brake Test
To carry out this test, proceed as follows:
zWarm the brakes by slowing the vehicle a few times from 80–32 km/h (50–20 mph) using light
braking applications. At highway speeds of 89–97 km/h (50– 60 mph), apply the brake using a
light pedal force.
z Accelerate to 89–97 km/h (55–60 mph).
z Lightly apply the brakes and slow the vehicle to 30 km/h (20 mph).
z A brake vibration noise can be felt in the steering wheel, seat or brake pedal. A brake noise can
be heard upon brake application and diminish when the brake is released.
Road Test Over Bumps
To carry out this test, proceed as follows: Klj . 7 ba
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z
Drive the vehicle over a bump or rough surface one wheel at a time to determine if the noise is
coming from the front or the back and the left or the right side of the vehicle.
z Proceed as necessary.
Neutral Engine Run- Up (NERU) Test
To carry out this test, proceed as follows:
zInstall a tachometer.
z Increase the engine rpm up from an idle to approximately 4000 rpm while in PARK on front
wheel drive vehicles with automatic transmissions, or NEUTRAL for all other vehicles. Note the
engine rpm and, if possible, determine the vibration frequency.
z Attempt to identify what part of the vehicle the concern is coming from.
z Attempt to identify the source of the concern.
z Proceed as necessary.
Drive Engine Run- Up (DERU) Load Test
To carry out this test, proceed as follows:
z WARNING: Block the front and rear wheels, and apply the parking brake and the
service brake, or injury to personnel can result.
CAUTION: Do not carry out the Engine Load Test for more than five seconds or
damage to the transmission or transaxle can result.
Block the front and rear wheels.
z Apply the parking brake and the service brake.
z Install a tachometer.
z Shift the transmission into DRIVE, and increase and decrease the engine rpm between an idle
to approximately 2000 rpm. Note the engine rpm and, if possible, determine the vibration
frequency.
z Repeat the test in REVERSE.
z If the vibration/noise is duplicated when carrying out this test, inspect the engine and
transmission or transaxle mounts.
z If the concern is definitely engine speed- related, carry out the Engine Accessory Test to narrow
down the source.
z Proceed as necessary.
Engine Accessory Test
To carry out this test, proceed as follows:
z WARNING: Block the front and rear wheels, and apply the parking brake and the
service brake, or injury to personnel can result.
CAUTION: Limit engine running time to one minute or less with belts removed or
serious engine damage will result. Klj . 8 ba
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NOTE:
A serpentine drive belt decreases the usefulness of this test. In these cases, use a
vibration analyzer, such as the VA, to pinpoint accessory vibrations. An electronic listening
device, such as an EngineEAR, will also help to identify noises from specific accessories.
Remove the accessory drive belts.
z Increase the engine rpm to where the concern occurs.
z If the vibration/noise is duplicated when carrying out this test, the belts and accessories are not
sources.
z If the vibration/noise was not duplicated when carrying out this test, install each accessory belt,
one at a time, to locate the source.
Vehicle Cold Soak Procedure
To carry out this procedure, proceed as follows:
zTest preparations include matching customer conditions (if known). If not known, document the
test conditions: gear selection and engine rpm. Monitor the vibration/noise duration with a watch
for up to three minutes.
z Park the vehicle where testing will occur. The vehicle must remain at or below the concern
temperature (if known) for 6- 8 hours.
z Before starting the engine, conduct a visual inspection under the hood.
z Turn the key on, but do not start the engine. Listen for the fuel pump, anti- lock brake system
(ABS) and air suspension system noises.
z Start the engine.
z CAUTION: Never probe moving parts.
Isolate the vibration/noise by carefully listening. Move around the vehicle while listening to find
the general location of the vibration/noise. Then, search for a more precise location by using a
stethoscope or EngineEAR.
z GO to Symptom Chart — Idle Noise/Vibration to assist with the diagnosis.
6: Check OASIS/TSBs/Repair History
After verifying the customer concern, check for OASIS reports, TSBs and the vehicle repair history for
related concerns. If information relating to a diagnosis/repair is found, carry out the procedure(s)
specified in that information.
If no information is available from these sources, carry out the vehicle preliminary inspection to
eliminate any obvious faults.
7: Diagnostic Procedure
Qualifying the concern by the particular sensation present can help narrow down the concern. Always
use the "symptom" to "system" to "component" to "cause" diagnosis technique. This diagnostic method
divides the problem into related areas to correct the customer concern.
zVerify the "symptom".
z Determine which "system(s)" can cause the "symptom".
„If a vibration concern is vehicle speed related, the tire and wheel rpm/frequency or
driveshaft frequency should be calculated.
„ If a vibration concern is engine speed related, the engine, engine accessory or engine
firing frequencies should be calculated. Klj . 9 ba
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