Before you use the finished product on the road, check the regulations in your state for trailer licensing and lighting.
Remove Extra Supports
Use a portable metal saw to cut off the roof supports from the RV frame, and set them aside. On the front end of the RV, measure 1 foot up from the bottom of the frame on each vertical support. Cut off each of the vertical supports at this mark. These supports are the base of the trailer's front rail. On the left, right, and back of the RV frame, cut off the vertical supports. Grind down each support so that the cut edge sits flush with the base of the frame.
Add the Deck
Measure the size of your trailer frame with a measuring tape, taking into account the indentations for the wheels. Purchase heavy-duty sheet metal to cover the surface area of the trailer, and cut it to the correct size and shape. The edges of the sheet should line up with the outside edge of the RV frame. Weld the sheet onto the exterior frame and cross supports.
Measure the distance between your car's wheels, and measure the wheel's width. Use that information to draw the tread path onto the trailer deck, placing one track on each side. Cut sheets of diamond tread plate to cover the track. Bolt or weld the tread plate to the trailer deck to give your vehicle's wheels traction on the trailer.
Complete the Front Rail and Add Tie-Down Rings
Measure the distance between the outermost vertical supports on the front of the frame. Cut a piece of steel tubing to that length. Alternatively, use one of the vertical supports you removed, and cut it down to size. Use a welder to attach the section across the top of the vertical supports to complete the front rail.
On the short sides of the trailer, install one U-clamp on each corner. Drill holes through the trailer frame to accommodate the ends of the U. Drop the clamp in place, with the rounded part of the U sticking up from the trailer frame, and fasten the bracket underneath the trailer frame with the included nuts. Weld the clamp and bracket to the trailer frame for additional stability.
Install one U-clamp on each corner of the long sides. Starting from each of these clamps, measure 3 feet toward the center, and make a mark. Install a U-clamp at each of the four marks. The U-shaped clamps accommodate the hooks of your vehicle tie-down straps.
Purchase a trailer fender for each of the wheels on your RV frame. If the frame has two wheels located next to each other, purchase a double fender. You can also salvage fenders or fabricate them by bending metal plates and rolling the edges. Position the fenders above the wheels, leaving space between the top of the wheel and the bottom interior of the fender. Bolt the fenders to the trailer frame with steel bolts.
Purchase a set of car trailer ramps with hooked ends. Set the ramps against the back of your trailer, and align the top ends with your tread tracks. Draw the hook locations onto the frame or the bed of your trailer, and use a metal saw to cut a small channel for the hooks.
How to Buy Car Trailer Supplies
Start your trailer-building project on the right foot by ordering supplies on eBay. Type the name of a product into the search bar, which you can find at the top of every page. Click on the Search button to see a list of products that match your keywords. Using the filters in the left column, you can refine the search to create a more tailored list of results.