Body Mount Kit

What body mounts do

On any body-on-frame truck or Jeep, the body does not bolt directly to the frame. A dozen or more rubber mounts cushion it, isolate road noise and vibration, and let the frame flex slightly without cracking the body. Over decades the rubber compresses, cracks and finally crumbles, which shows up as doors that no longer line up, a cab that creaks over bumps, body bolts sitting in a puddle of rust, and a rattle from the bed. On older Jeeps the mounts rot and the tub starts to rust at the mount points, so a body mount job is often paired with floor and frame repair.

Rubber or polyurethane

Factory-style rubber, such as the Omix-Ada CJ kits with upper mounts, lower bushings and steel sleeve spacers, gives the quietest ride and the original feel. It is the right call for a restoration or a daily driver where comfort matters most. Polyurethane, the Energy Suspension HYPER-FLEX and Prothane kits, is firmer and far more resistant to oil, ozone and salt, so it holds its shape for many years and tightens the connection between body and frame. The side effect is slightly more road noise and vibration transmitted into the cab, which most off-road owners accept.

Billet aluminum spacers, like the Artec 1.25 inch TJ set, are a different product. They do not cushion anything; they raise the body a fixed amount and are a precise alternative to plastic body lift blocks. Use them with new rubber or urethane pads, not instead of them.

What a kit includes

• Count the pieces. A Montero kit has 18 pieces, a Bronco set 16, a CJ rubber kit 36. Compare to the number of mount points on your vehicle so you are not short two bushings on a Saturday afternoon.
• Most kits are bushings only. Body bolts, washers, nuts and the radiator support or grille mount are usually not included, and 30 year old bolts rarely come out reusable. Order a bolt kit at the same time.
• Some mounts have a steel ring molded into the end to keep the bolt from crushing the material. Check that the kit matches the mount style at each position; front, mid and rear mounts often differ.
• Fiberglass bodies on CJs use a different mounting kit than steel tubs, with mounting plates and a roll of rubber strip rather than individual pads.

Installation notes

Expect seized bolts. Soak them for a day with penetrating oil, and plan to cut or drill a few. Support the body at several points and lift it only an inch or two at a time, watching the steering shaft, brake lines, fuel filler, wiring and shifters. Replace mounts one side at a time so the body never floats free of the frame. Clean the frame perches to bare metal and treat rust before installing new mounts, because trapped moisture at the mount is what killed the old ones.

Torque the new bolts to the factory figure, then drive a few hundred miles and recheck. Polyurethane benefits from a smear of the silicone grease supplied with the kit on any surface that moves against metal, which prevents the squeak that gives urethane a bad name. Afterward, check door, hood and tailgate alignment; fresh mounts raise a sagging body enough to change the gaps.

Pairing with a body lift

If you are already dropping the body for a lift, replacing the mounts at the same time costs almost nothing extra in labor. Many owners run new urethane pads under aluminum or nylon lift spacers to get both a quiet mount and the extra tire clearance in one job.