Mustang
Cobra - Mustang GT
Mechanical
information specific to Mustang, Mustang Cobra,
and Mustang GT
All
models of the Mustang tend to wear their clutches
and develop symptoms in about the same way.
What is said here about Cobras is likely to
be true of 6-cylinder Mustangs.
Clutch
& Transmission:
Mustangs
tend to need a clutch between 60,000 miles
and 100,000 miles. Average drivers will begin
to feel symptoms around 70,000. Performance
drivers or inexperienced drivers should not
be surprised to have problems at much lower
mileage.
Sometimes
a clutch simply fails with no notice. But,
other than clutches 'blown' during overaggressive
performance maneuvers, it is much more common
for warning symptoms to precede actual total
failure. Although simple slippage may be the
first symptom you recognize, it is much more
likely you will feel one of the particular
syndromes that are common to Mustangs.
Initial
clutch symptoms usually fall into one of three
categories:
| Hard
Pedal
The clutch pedal, over time, slowly,
becomes harder to push. About the time
this becomes noticeable, there are often
noises that accompany the operation
of the clutch. |
Clutch
Chatter
Upon
engagement, the vehicle shudders and
shakes. This may be evident in the entire
vehicle or simply in the clutch pedal.
As the chatter increases, usually noises
will accompany the operation of the
clutch. |
Strange
Noises
Whenever
the clutch pedal is depressed, noises
occur. Most commonly, there will be
a squeaking, scraping noise as the pedal
is depressed and chatter or banging
as the pedal is released. |
Hard
Pedal:
Most
Mustang clutches are cable operated. Hard
pedal may be caused by a worn, sticking cable.
Be sure to check the cable when replacing
the clutch. There is even good reason to argue
that the cable should be replaced at the same
time as the clutch whether or not there is
any noticeable wear and tear.
Address
this symptom as soon as it is recognized.
Continued use of the clutch after a hard pedal
exists WILL damage other costly items.
Normal
clutch wear will cause the pedal to become
harder to push. Geometry of the clutch pressure
plate causes pressure from the release bearing
to push at an increasingly oblique angle as
a clutch wears. This normal progression will
eventually case damage to one or more of the
following items:
Clutch
Cable
Clutch Pedal Bracket
Clutch Adjuster Quadrant
Transmission Front Bearing Cover
Hard
Pedal can be caused by failure of the clutch
cable. When a cable binds, it will soon break,
potentially leaving you stranded.
Another
cause for hard pedal is failure of the clutch
release bearing. More commonly than on other
vehicles, Mustangs suffer from clutch release
bearing failure. Usually the initial cause
is wear of the clutch release fork and the
fork pivot ball. As the pivot and socket wear,
proper geometry is compromised and lateral
pressure on the release bearing is increased.
When the bearing fails, damage to the transmission
front bearing cover follows quickly.
Clutch
Chatter (a vibration or repeated
'jumping' as the clutch is engaged):
Chatter
can be caused by a damaged pressure plate,
clutch disc, flywheel, pilot bearing, motor
mounts, transmission mount, universal joints,
or engine misfire. Diagnosis is required.
Simply replacing the clutch may NOT be the
answer.
Mustangs
suffer more than most from overheated flywheels.
'Hotspots' begin to appear on the flywheel
when its surface temperature exceeds approximately
1500 degrees Fahrenheit. Stock flywheels do
not dissipate heat fast enough to prevent
reaching this threshold. The flywheel surface
overheats and the metal changes its physical
properties. Surface wear and friction coefficient
become uneven. This causes the clutch to engage
unevenly and vibrate. Always inspect flywheels
carefully prior to resurfacing. Once
the surface is ground by a diamond wheel,
you will not be able to see the surface irregularities.
You will end up installing a bad flywheel
and having to redo the entire job immediately.
For
most drivers, I recommend using only a Ford
Motorsport steel billet replacement flywheel.
For out-and-out performance drivers, there
are several brands of lightweight aluminum
racing flywheels available.
Prior
to replacing your clutch, make sure that the
engine is running correctly. Many times a
misfire under load is misdiagnosed as a clutch
problem.
To
cure clutch chatter, replace the entire clutch
kit (plate, disc, release bearing, and pilot
bearing), carefully inspect the flywheel and
replace if hotspots are present. Check motor
mounts and transmission mount for breakage
and/or sagging. Inspect universal joints.
Strange
Noises: Why do Mustang clutches emit
such loud failure notices?!!!
No
matter what year or model, it seems to be
a fact of Mustang ownership that eventually
you will hear a loud frightening noise. When
this happens in conjunction with operation
of the clutch, quickly get the vehicle in
for diagnosis and repair!
Friction
and binding cause noises. They also cause
damage! The T5 transmissions used in Mustangs
(even the Z spec) are relatively fragile and
subject to damage by malfunctioning clutch
components. Don't wait for the noise to go
away. It won't. It will only get more expensive.
Get the vehicle into the shop, now.
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us at Norcal Mustang Club - Wildhorses.com
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us for more Mustang clutch information 
Questions?
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