Ford
Truck - F150, F250, F350, Ranger
Mechanical
information specific to Ford Trucks.
Clutch:
Ford
scales their clutch capacity, in a remarkably
reasonable progression, in accord with the
size, weight, and torque capacity of their
truck models. A four-cylinder Ranger has a
clutch that is relatively light weight, similar
to many passenger cars. An F350 Super Duty
Turbo Diesel comes with a huge, heavy-duty
clutch that weighs more than 45 pounds. Average
usage seems to scale accordingly. The bigger
the truck, the longer service you might expect
from the clutch. Rangers average approximately
70,000 miles. F350 Diesels average more than
120,000 miles.
When
replacing a clutch, be wary of non-stock parts.
Even purported performance upgrades should
be investigated for quality and appropriateness
for your particular application.
Stock
truck clutches are manufactured with a relatively
soft friction material that is coupled with
a strongly sprung pressure plate. The pairing
assures smooth, controllable, quiet engagement
with heavy load/torque capacity and a reasonable
life expectancy. Deviating from stock configuration
tends to introduce undesirable operation features.
A clutch that engages harshly and abruptly,
or that chatters and engages unpredictably,
can be frustrating and dangerous when backing
a load up a steep drive or pulling a boat
up a wet ramp.
When
replacing a clutch, replace the entire clutch
kit (plate, disc, release bearing, and pilot
bearing), carefully inspect the flywheel and
replace if hotspots are present (if reusing
the flywheel, always resurface with a diamond-wheel
flywheel grinder). Check the clutch master
and slave cylinders, and the tube that connects
the two cylinders, for leaks. Inspect motor
mounts and transmission mount for breakage
and/or sagging. Inspect universal joints.
Hydraulics:
Ford
Truck Clutches are hydraulically operated.
The system consists of a master cylinder,
slave cylinder, and a hose or tube that connects
the two. Even the smallest of leaks in this
system will cause problems shifting. Location
of the slave cylinder varies (depending upon
year/model) between external, mounted to the
side of the transmission bellhousing, and
internal, inside the bellhousing mounted on
the transmission input shaft. either clutch
cylinder
A
leak in either clutch cylinder is reason to
consider replacing both. This system in Ford
trucks has proven to be fragile and prone
to problems. Whatever caused one cylinder
to fail, the other has been subjected to the
same influences. No one wants
to make two trips, in quick succession, to
the repair shop.
Replacing
these cylinders is a job for a professional.
While the actual unbolting and reattaching
of the parts is reasonably straight-forward,
bleeding the system properly is tedious and
unreasonably complicated. Even in a clutch
shop, the process of bleeding the hydraulic
system will often require more time than the
actual exchange of parts.
How to bleed
Ford Truck internal slave clutch hydraulic
systems:
Remove the clutch master
cylinder from the firewall and clutch pedal
(that's right, remove it!). Leave the hydraulic
line connected.
Angle the master cylinder so that the line
is above any other part of the cylinder (basically
upside down) This allows all the air in the
cylinder to rise to the top and accumulate
immediately adjacent to the line.
Have a helper under the vehicle crack the
slave cylinder bleeder valve open. On models
where it is possible to reach, have the helper
hold a rubber-gloved finger over the open
valve orifice so that it acts as a one-way
valve and allows no air to enter the slave
cylinder on the return stroke.
Holding the master cylinder in this position,
use your other hand to smoothly pump the cylinder
rod and piston several times. Make sure you
depress the piston completely each time. Do
this slowly and smoothly. You have to push
the air bubble all the way down and through
the slave cylinder. Rest after three or four
strokes. Any rapid movement will disperse
the air throughout the cylinder, the fluid
will aerate (lots of little bubbles) and the
process will be unsuccessful. Be sure that
the master cylinder reservoir never goes dry.
When you decide you have done enough (?),
direct your helper to close the valve during
the final depression stroke. Ideally, the
valve would be completely closed while the
piston is being depressed, not after it hits
bottom.
Reinstall the master cylinder. Hope for the
best.
-----------------
You should try to have three people to do
this job. One to work the cylinder, one to
work the bleeder valve, and one to keep the
master cylinder from running dry.
When we do this job in our shops we always
try to keep the vehicle overnight so that
any air that was aerated into the fluid will
condense and we will find the problem the
next morning rather than having the customer
stuck with shifting problems.
We strongly recommend that this be done in
a shop that specializes in clutches. The chances
of a relatively inexperienced DIYer or even
an average general mechanic getting it right
the first time are slim.
Email
us for more Ford Truck information 
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