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keep the trailer from rolling away from you. Properly
adjusted uni-servo or duo-servo type brakes will
prevent you from moving the trailer back more than
a few inches. Free-backing type brakes will initially
provide rolling resistance, but continued force on the
board will switch them into free-backing mode, and
you'll be able to move the trailer backwards.
If you have uni-servo or duo-servo brakes, and
stroking the actuator (as described above) causes the
trailer to roll away from you freely or with only minimal
resistance, the brakes are NOT applying properly.
If you have free-backing brakes and stroking the
actuator (as described above) causes the trailer to roll
away without initial resistance, then the brakes are
NOT applying properly. The brake system MUST be
evaluated to determine the cause of the problem and
corrective action MUST be taken before the trailer
is used. Use this procedure each time you tow your
trailer to check your surge brake system operation.
4.3.5.4 Test Surge Breakaway System
Before towing, check that the breakaway lever and
lanyard are properly positioned. If the breakaway lever
and lanyard are not located correctly due to either
the lanyard being pulled during use or by accident, it
MUST be reset prior to the trailer being moved.
See the Surge Brake Actuator manual for the correct
resetting and testing procedure.
^
WARNING
The breakaway system is designed to
operate if the trailer separates from the tow
vehicle.
DO NOT use the breakaway system as a
parking brake.
4.4 Uncouple Trailer
Follow these steps to uncouple trailer from the tow
vehicle:
Park the trailer on a fi rm level surface and block
1.
trailer tires.
Disconnect electrical connector.
2.
Disconnect breakaway brake switch lanyard.
3.
Disconnect safety chains from tow vehicle.
4.
Unlock the coupler and open it.
5.
Before extending jack, make certain the ground
6.
surface below the jack pad will support the tongue
load.
Coupling To Tow Vehicle
Rotate jack handle to extend the jack and transfer
7.
the weight of the trailer tongue to the jack.
Raise the trailer coupler above the tow vehicle
8.
hitch.
Drive tow vehicle forward.
9.
4.5 Tongue Weight
It is critical to have a portion of the trailer load carried
by the tow vehicle. That is, the trailer tongue must
exert a downward force on the hitch. This is necessary
for two reasons. First, the proper amount of tongue
weight is necessary for the tow vehicle to be able
to maintain control of the tow vehicle/trailer system.
If, for example, the tongue exerts an upward pull on
the hitch, instead of pushing down on it (because the
trailer is overloaded behind its axle(s)), the rear wheel
of the tow vehicle can lose traction or grip and cause
loss of control. Also, even if there is some weight on
the tongue, but not enough weight on the tongue,
the trailer can become unstable at high speeds.
Remember, the faster you go the more likely the trailer
is to sway.
If there is too much tongue weight, the tow vehicle is
prone to jack-knife. The front wheels of the tow vehicle
can be too lightly loaded and cause loss of steering
control and traction, if the front wheels are driving.
In addition to tow vehicle control, tongue weight is
necessary to insure that the trailer axle(s) do not
exceed their Gross Axle Weight Rating (GAWR).
In the following table, the second column shows
the rule of thumb percentage of total weight of the
trailer plus its cargo (Gross Trailer Weight, or "GTW")
that should appear on the tongue of the trailer. For
example, a large trailer with a loaded weight of 6,000
pounds, should have 10-15% of 6,000 pounds (600-
900 lbs.) on the hitch.
Tongue Weight as a Percentage of Loaded Trailer
Type of Hitch
Ball Hitch or
Ring & Pintle
The numbers quoted are for example purposes only
and should be tailored to the specifi c trailer.
For questions regarding the actual percent of tongue
weight for the trailer, check with the manufacturer
for specifi cs.
33
Weight
Percentage
10-15% for large trailers
6-10% for small trailers
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