When body mount bushings begin to wear and break, the signs are obvious. The ride will be rougher, there may be grinding or squeaking noises from metal-on-metal contact, and the bushings themselves will look broken and even crumbled. If they're there at all. Older vehicles that have seen hard use or that have been parked in less than ideal storage may require bushing replacement. Body bushings are relatively easy to remove and replace, though some gymnastics may be required to get to them.
The bushings on a vehicle are important, so if you aren't sure what they are or why they warrant attention, read this first.
Replacing Body Mount Bushings
Most bushings will be found in pairs. On the body, they will usually be directly opposing one another (left side, right side) on the vehicle, connecting the chassis frame to the vehicle's body framing. Replacement is a matter of disconnecting the bolts and lifting the vehicle's body off of the frame just enough to remove the old bushing and put in the new one.
The trick here is to lift just enough to get the bushing out and replaced without lifting so much that you tweak the frame itself. Lifting the body frame just ahead of or behind the bushing mount with a jack that has a wide head or by using a 2x4 or other piece of lumber that is several inches long (placed on top of the jack) will help. This spreads the lift point to avoid bending the frame. A lift of less than an inch is usually all that's required.
Replace bushings in pairs, at minimum. If body bushings are being replaced because of wear, it's a good idea to replace all of them on the vehicle rather than just those showing wear.
When bushings are replaced, new bolts and hardware should also be installed to hold them in. This helps avoid bolt stretching and added corrosion. These replacement parts are usually included with bushing kits. Be sure to tighten bolts to torque specifications once the vehicle's weight is back on the bushing.
Most vehicles have 6 to 10 body bushings in total.