2003 GMC Sonoma Owner's Manual - Page 260

Hitches It's important to have the correct hitch equipment. Crosswinds, large trucks going by and rough roads are a few reasons why you'll need the right hitch. Here are some rules to follow: If you use a step-bumper hitch, your bumper could be damaged in sharp turns. Make sure you have ample room when turning to avoid contact between the trailer and the bumper. 0 on the bumper. For heavier trailers, follow the trailer or hitch manufacturer's recommendation for attaching safety chains. Always leave just enough slack so you can turn with your rig. Never allow safety chains to drag on the ground. Trailer Brakes If your trailer weighs more than 1,000 Ibs. (450 kg) loaded, then it needs its own brake-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's brake system can tap into the vehicle's hydraulic brake system only if: The trailer parts can withstand 3,000 psi (20 650 kPa) of pressure. The trailer's brake system will use less than 0.02 cubic inch (0.3 CC) of fluid from your vehicle's master cylinder. Otherwise, both braking systems won't work well. You could even lose your brakes. 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. If you'll be pulling a trailer that, when loaded, will weigh more than 3,500 Ibs. (1 589 kg) be sure to use a properly mounted, weight-distributing hitch and sway control of the proper size. This equipment is very important for proper vehicle loading and good handling when you're driving. 0 If your vehicle has the bumper delete option, do not bolt any type of hitch to the close-out panel. The close-out panel will not support a hitch. Safety Chains You should always attach chains between your vehicle and your trailer. Cross the safety chains under the tongue of the trailer to help prevent the tongue from contacting 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. For trailers up to 3,500 Ibs. (1 589 kg) you may attach the safety chains to the attaching points 4-59