GMC 1995 Jimmy Owner's Manual page 197

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 if 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 and do not attach them to the bumper. 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 so you'll be able to install, adjust and
maintain them properly.
Your trailer brakes system can tap into vehicle's hydraulic brake system
except:
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.
Will the trailer parts take 3,000 psi (20 650 Wa) 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.
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