If your tandem axle trailer's suspension system has worn out and your axles need replacing as a result, you can upgrade your trailer's suspension with a tandem axle slipper spring kit. The slipper spring's high-fatigue steel design can be installed on trailers to absorb the impact from hauling heavy loads. The slipper spring has a larger load capacity and fewer moving parts, compared to the double-eye leaf spring alternative. New slipper springs will improve your trailer's handling, while protecting the axles from damage.
Raise the trailer frame from the ground by placing blocks under the front and rear corners of the trailer.
Install an equaliser bar to the middle hanger on each side of the trailer. Fasten the centre hole of the equaliser bars to the hangers with a bolt. Make sure the equaliser bars are oriented with the lower keeper bolt holes forward of the upper eye bolt holes.
Install the forward slipper springs to either side of the trailer. Slide the slipper ends of the springs through the front ends of the middle equaliser bars on either side of the trailer. Attach the slippers to the equaliser bars using keeper bolts.
Set the front axle across the centre slipper spring seats of the forward springs. Raise one forward slipper spring at a time, attaching the eye bolt bushing to the forward spring hanger using a spring bolt. The front axle should be suspended across the forward slipper springs.
Fasten the front axle to the centres of the forward slipper springs. Attach a U-bolt and retainer bracket on each side, securing the axle to the springs.
Install the rear slipper springs. Attach the eye bolt ends of the springs to the rear holes of the equaliser bars using spring bolts.
Set the rear axle across the centre slipper spring seats of the rear springs. Raise each spring, and slide the slipper end through the rear slipper hanger on each side of the trailer. The rear axle should be suspended across the rear slipper springs.
Secure the rear axle to the centre of the rear slipper springs. Attach either side of the axle to the springs using a U-bolt and retainer bracket.
Tighten all the bolts to the manufacturer's torque specifications, using a torque wrench. Remove the blocks and jack stands and lower the trailer.
Make sure to align the axles according to the manufacturer's specifications.