Ford F-150 Owner's Manual page 267

When hooking-up a trailer using a weight-distributing hitch, always use
the following procedure:
1. Park the loaded vehicle (without the trailer) on a level surface.
2. Measure the height to the top of the vehicle front wheel opening on
the fender, this is H1.
3. Securely attach the loaded trailer to the vehicle without the
weight-distributing bars connected.
4. Measure the height to the top of the vehicle front wheel opening on
the fender a second time, this is H2.
5. Install and adjust the tension in the weight-distributing bars so that
the height of the vehicle's front wheel opening on the fender is
approximately halfway between H1 and H2.
6. Check that the trailer is level or slightly nose down toward the vehicle.
If not, adjust the ball height accordingly and repeat Steps 1–6.
7. Lock bar tension adjuster in place.
8. Check that the trailer tongue is securely attached and locked to the
hitch.
9. Install safety chains, lighting, and trailer brake controls as required by
law or the trailer manufacturer.
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 the 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 installed properly and adjusted to the manufacturer's specifications. The
trailer brakes must meet local and Federal regulations.
The braking system of the tow vehicle is rated for operation at
the GVWR not GCWR.
Separate functioning brake systems are required for safe control
of towed vehicles and trailers weighing more than 1500 pounds
(680 kilograms) when loaded.
2013 F-150 (f12)
Owners Guide gf, 1st Printing
USA (fus)
Towing 267