2003 GMC Safari Owner's Manual - Page 211

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: Follow the manufacturer's recommendation for attaching safety chains and do not attach them to the bumper. Always leave just enough slackso you canturn 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 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. If you'll be pulling a trailer that, when loaded, will weigh more than 2,000 Ibs. (900 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. Will you have to make any holes in the body of your vehicle when you install a trailer hitch? If you do, then be sure to seal the holes later when you remove the hitch. If you don't seal them, deadly carbon monoxide (CO) from your exhaust can get into your vehicle. Dirt and water can, too. Your trailer brake system can tap into your vehicle's hydraulic brake system, except: Don't tap into your vehicle's brake system if the trailer's brake system will use more than0.02 cubic inch (0.3 cc) 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 kPa) of pressure? If not, the trailer brake system must not be used with your vehicle. 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 tonguefrom contacting the roadif it becomes separated from the hitch. Instructions about safety chains may beprovided by the hitchmanufacturer or bythe trailer manufacturer. 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. 4-36