FORD 2013 Expedition v.2 - Manual (Page 261)

8. With the ignition on and all doors closed, let your vehicle (now with
trailer and weight distributing bars connected) sit for a few minutes
to let the air suspension re-settle.
9. Re-measure the height of the top of the front wheel opening,
repeating Steps 7-9 as necessary to obtain a fender height
approximately halfway between H1 and H2 after the air suspension
has settled.
10. Check that the trailer is level. If it is not level, remove the trailer,
adjust the ball height accordingly, and repeat Steps 4–10.
Safety Chains
Note: Do not attach safety chains to the bumper.
Always connect the trailer’s safety chains to the frame or hook retainers
of your vehicle hitch.
To connect the trailer’s safety chains, cross the chains under the trailer
tongue and allow enough slack for turning tight corners. Do not allow the
chains to drag on the ground.
Trailer Brakes
WARNING: 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.
Electric brakes and manual, automatic or surge-type trailer brakes are
safe if you install them properly and adjust them to the manufacturer’s
specifications. The trailer brakes must meet local and federal regulations.
The rating for the tow vehicle’s braking system operation is at
the gross vehicle weight rating, not the gross combined weight
rating.
Separate functioning brake systems are required for safe control
of towed vehicles and trailers weighing more than 1500 pounds
(680 kilograms) when loaded.
260 Towing
2013 Expedition (exd)
Owners Guide gf, 2nd Printing, October 2012
USA (fus)