Weight distributing hitch
When hooking up a trailer using a load equalizing hitch, always use the
following procedure:
1. Park the unloaded vehicle on a level surface. With the ignition in the
ON position and all doors closed, allow the vehicle to stand (without
passengers) for several minutes so that it can level.
2. Turn the air suspension (if equipped) control to OFF.
3. Measure the height of a reference point on the front and rear bumpers
at the center of the vehicle.
4. Attach the trailer to the vehicle and adjust the hitch equalizers so that
the front bumper height is within a
1 2” (13 mm) of the reference point.
After proper adjustment, the rear bumper should be no higher than in
Step 3.
5. Turn the air suspension (if equipped) control to ON.
Note:Adjusting a weight distributing hitch so the rear bumper of the
vehicle is higher than it was unloaded will defeat the function of the
weight distributing hitch and may cause unpredictable handling.
Safety chains
Always connect the trailer’s safety chains to the frame or hook retainers
of the vehicle hitch. To connect the trailer’s safety chains, cross the
chains under the trailer tongue and allow slack for turning corners.
If you use a rental trailer, follow the instructions that the rental agency
gives to you.
Do not attach safety chains to the bumper.
Trailer brakes
Electric brakes and manual, automatic or surge-type trailer brakes are
safe if installed properly and adjusted to the manufacturer’s
specifications. The trailer brakes must meet local and Federal
regulations.
Do not connect a trailer’s hydraulic brake system directly to your
vehicle’s brake system. Your vehicle may not have enough
braking power and your chances of having a collision greatly increase.
The braking system of the tow vehicle is rated for operation at the
GVWR not GCWR.
2008 Expedition(exd)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
261
If the steering wanders or pulls, check for:
•Underinflated tire(s) on any wheel(s)
•Uneven vehicle loading
•High crown in center of road
•High crosswinds
•Wheels out of alignment
•Loose or worn suspension components
Variable assist steering
Your vehicle is equipped with variable assist power steering. At low
engine RPM, steering assist will adjust to reduce efforts and improve low
speed maneuverability. At high engine RPM, the assist will adjust to
improve steering feel at high speeds.
If the amount of effort required to steer your vehicle changes while
driving at a constant engine RPM, have the power steering system
checked by your authorized dealer.
AIR SUSPENSION SYSTEM (IF EQUIPPED)
The air suspension system is designed to improve ride, handling and
general vehicle performance during:
•Certain road conditions
•Steering maneuvers
•Braking
•Acceleration
This system keeps the rear of your vehicle at a constant level by
automatically adding air or releasing air from the springs. If you exceed
the load limit, the rear air suspension may not operate. The air
suspension system will stay active for 40 minutes after the ignition is
turned off to accommodate any load changes. (The air compressor may
run when the vehicle is off; this is normal.)
The air suspension system can be enabled or disabled through the
message center. Refer toMessage centerin theDriver Controlschapter.
If the system is off, the rear air suspension will not operate and will not
raise (pump) or lower (vent) while the vehicle is not moving. However, if
the system determines that the vehicle is low or high and needs to make
a height adjustment while driving at speeds above 15 mph (24 km/h), the
system will pump or vent as required. Normal vehicle operation does not
require any action by the driver.
2008 Expedition(exd)
Owners Guide (post-2002-fmt)
USA(fus)
Driving
278
