If you recently bought a single-axle utility trailer kit, you may need to install the axle to the frame. A single-axle utility trailer uses a leaf spring suspension system to support the cargo weight and to absorb road impact while hauling. The trailer's axle is suspended from two leaf springs that protect the axle and your cargo from damage. The leaf springs also keep your trailer's axle aligned, perpendicular to the direction of travel. Once you've installed the axle to your trailer, compare the distance between the wheels and the trailer tongue to ensure proper alignment.
Raise the trailer frame using a jack -- or the help of a second person -- and place the four corners on jack stands or blocks.
Locate the front and rear shackle hangers on either side of the trailer. Attach one end of each leaf spring to the front shackle hanger on each side of the trailer, using a bolt and socket wrench. Allow the leaf springs to hang down to the ground.
Place the axle across the centres of the leaf springs. Raising one leaf spring at a time, attach each leaf spring to its rear shackle hanger on either side of the trailer, using a bolt and socket wrench. The axle should be suspended from the leaf springs.
Secure the ends of the axle to the centres of the leaf springs using U-bolts, retainer brackets and a socket wrench.
Tighten all the bolts to the manufacturer's torque specifications, using a torque wrench. Removethe blocks and jack stands and lower the trailer.
Perform this activity with the help of a second person.