Install a Trailer Hitch

As a building maintenance tech, I carry a lot of stuff to and from the job site. After trading my aging pickup for a more fuel-efficient, compact grocery getter, I realized that although my new vehicle could haul of all my tools, I would occasionally need to tow a trailer loaded with large materials. And that meant installing a receiver hitch.

A receiver hitch consists of a square or round steel tube that bolts to your vehicle’s frame and accepts a draw bar with a towing ball (see photo, below). Many trucks and SUVs come with a factory-installed receiver hitch, but most cars, vans and smaller crossover vehicles do not. Luckily, thanks to the large variety of after-market hitches, you should be able to find one that will fit your vehicle, and you’ll only need basic mechanics’ tools to install it yourself.

Typical hitch components

The right hitch
Before you buy a receiver hitch, you need to know the towing capacity of your vehicle and how much weight you plan to pull. Trailers are rated by gross trailer weight (GTW — the total weight of the trailer and its load) and tongue weight (the downward force of the trailer on the hitch ball — typically about 10 percent of the GTW).

You can find the towing capacity and tongue-weight limit of your vehicle in the owner’s manual, and you should never exceed those limits. (If you’ve misplaced the owner’s manual, check online or consult a local dealership to determine your vehicle’s towing capacity.) You may find more than one rating, depending on whether you’re using a weight-carrying hitch or a weight-distributing hitch and whether you’re towing a trailer that’s equipped with auxiliary brakes.

Once you’ve determined how much weight you’ll be towing and what your vehicle is rated for, you’ll need to choose a receiver hitch that can handle the load (see “Understanding Weight Ratings,” in PDF below). Hitches are rated in five classes according to GTW, and both the GTW and tongue weight are labeled (see “Choosing the Right Hitch,” in PDF below). The most common type of receiver hitch is the weight-carrying variety, which is designed to support all of the trailer’s tongue weight. The less common weight-distributing hitch uses long rods called spring bars to exert leverage on the towing vehicle’s frame, spreading the tongue weight to all four wheels instead of just the rear wheels. This allows the vehicle to remain more level and stable when pulling heavy loads. (With a weight-carrying hitch, a heavy load would make the rear of the vehicle lower than the front.)

Typical installation
With most vehicles, installing a hitch simply involves raising the vehicle and bolting the hitch to the frame. (Be sure to carefully follow all of the hitch manufacturer’s instructions.)

Start by jacking up the vehicle’s rear end and setting it on jack stands — never use only the jack to hold a vehicle while you are working on it. Locate the bolt holes in the vehicle’s frame and remove any debris. (You may need to remove the spare tire to access the frame holes.) Place the bolts, washers and spacers (if required) into the frame holes (photo 1). One handy trick, especially if your installation requires vertical as well as horizontal bolts, is to lightly tape the bolts in place with duct tape so they stay put when you position the hitch.

Insert the mounting bolts and related hardware into the frame holes. Although this photo shows the bolts fully inserted for clarity, you’ll need to insert them so that they barely protrude through the frame holes.

Once the hitch is in place, push the bolts through the mounting holes (photo 2). Some hitches are heavy, and lining up all of the holes and bolts can be a bit tricky to do single-handedly, so a helper makes the job easier. If necessary, use a sharp utility knife to trim away any bumper molding or fascia that prohibits the hitch from mounting correctly.

Carefully lift the receiver hitch into position and then push the mounting bolts fully through the frame holes and the receiver’s mounting holes.

Tighten the nuts on the mounting bolts, making sure to follow any recommended torque requirements (photo 3). For added strength, use thread-locking compound such as Loc-Tite to better secure the nuts to the bolts.

Tighten the nuts on the mounting bolts. Ratcheting box-end wrenches make fast work of the initial tightening, but use a torque wrench for the final tightening.

All that’s left is to plug in a wiring loom extension (available at most auto parts stores if one didn’t come with your hitch) to power the trailer’s taillights, brake lights and turn signals. After that, you’re all set to tow your load.