GMC 1993 Jimmy Owner's Manual page 230

Your Driving and the Road
If your vehicle has a deadweight hitch and a tailgate-mounted spare tire, and
your trailer has a winch
or tongue jack, you could have interference between
them.
Safety Chains
You should always attach chains between your vehicle and your trailer. Cross
the safety chains under the tongue of the trailer
so
that the tongue will not
drop to the road i f it becomes separated from the hitch. Instructions about
safety chains may be provided by the hitch manufacturer or
by
the trailer
manufacturer. Follow the manufacturer's recommendation for attaching safety
chains, Always leave just enough slack so you can turn with your
rig. And,
never allow safety chains to drag on the ground.
Trailer Brakes
If your trailer weighs
more than
1,000 pounds (450 kg) loaded, then it needs
its own brakes-and they must be adequate. Be sure
to read and follow the
instructions for the trailer brakes to install, adjust
and
maintain them properly.
And:
Don't tap into your vehicle's brake system if the trailer's brake system
will use more than 0.02 cubic inch ( 0 . 3 ~ ~ ) of fluid from your vehicle's
master cylinder. If it
does,
both braking systems won't work well. You
could even lose your brakes.
Wi l l the trailer brake parts take 3,000 psi (20 650 kPa) of pressure? If
not, the trailer brake system must not be used with your vehicle.
If everything checks out this far, then make the brake fluid tap at the
port on the master cylinder that sends fluid
to the rear brakes. But don't
use copper tubing for this. If you do,
it
will bend and finally break off.
Use steel brake tubing.
Driving with a Trailer
Towing a trailer requires a certain amount of experience. Before setting out
for the open road, you'll want to get to know your rig. Acquaint yourself with
the feel of handling and braking with the added weight of the trailer. And
always keep
in
mind that the vehicle you are driving is now
a
good deal
longer and not nearly so responsive as your vehicle is by itself.
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