The use of the Ford coil spring is what gives your passengers a smooth ride while in your vehicle. While it is just a spiral shaped piece of metal, it improves the quality of the ride far beyond what passengers experienced when leaf springs were borrowed from old stagecoach designs. Coil springs on the front suspension they are located between the upper and lower control arms or built into your strut, and on the rear they are mounted to either the axle housings or the trailing arms or built into the shocks. Most of the coil springs will last the life time of your Ford unless it is in an accident. On rare occasions they might break when they experience an extremely heavy load or the shocks are so worn out for an extended period of time placing stress on this suspension part finally breaking it, but this is not a common event. On some older models the coil spring has just lost it ability to basically hold its bounce. This usually occurs on models 30 to 40 years old but still not a common occurrence on Ford models. Because of the load the Ford coil springs are placed under between the A-frames, only a technician with the appropriate equipment can replace them on a car or truck. The only alternative for a Ford owner is to use the weight of their vehicle to compress the coil spring in an attempt to put it into place. This is dangerous and not always successful. In attempting to replace this suspension part, the spindle would have to be loosened at the top ball joint. Then the coil can be compressed by placing a jack under the lower A-frame and a long pry bar on the top. This is definitely a two man job if doing it at home in your garage.