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Replacing Coil Springs

Independent A-arm suspension upgrade

Just as gravity makes the human body sag over time, it can also cause our cars to droop. More specifically, routine wear and tear causes metal parts to fatigue; and, suspension components eventually tire of absorbing road impact while also supporting the weight of the car's body. New springs can restore the vehicle to its original height and ride quality. The focus of this story is how to replace old coil springs on vehicles that have independent A-arm suspensions.

Lift or Lower?

A saggy profile and sloppy ride are two indicators that the springs are at the end of their life cycles. When replacement is imminent, many car owners debate the merits of using OE-spec springs or substituting non-stock springs: shorter coils provide a lower center of gravity for better road-hugging/cornering and longer springs mean additional off-road ground clearance/fit for taller tires. Regardless of spring length, the replacement procedure is similar (although longer springs sometimes require removing additional components).

Most above-average-skilled home mechanics can replace their vehicles' coil springs. However, the job isn't without risk. Compressed coils store an incredible amount of energy. The key to the swap is to release this pent-up energy in a slow, controlled way. A coil that abruptly springs forth from its A-arm environs can inflict severe bodily harm.

Compression Chambers

Coil "uncoiling" can be done a number of ways. Probably the most popular is with a coil compressor tool, which can be easily borrowed or rented from many auto parts stores. This tool squeezes the coil and keeps it in a compressed state while it's removed from the A-arm. Once the coil is off the vehicle, the compressor tool's through-bolt can be slowly unscrewed to gradually allow the coil to return to its unloaded state. When used properly, coil compressors are a popular way to safely remove springs. However, if the tool is damaged or used incorrectly, mayhem can ensue.

Some pro mechanics prefer to use a hydraulic lift and floor jack to remove coil springs. Since these people perform the procedure day in and day out, they know exactly how high to lift the vehicle so that the A-arm can be slowly lowered with a floor jack, using the floor as an emergency stop so that the coil won't shoot out from the vehicle. Since judgment based on experience is required here, this method isn't recommended for the casual do-it-yourselfer.

The safest way to preserve human digits and limbs when removing coil springs is to add redundancy—combining the two methods above or possibly even securing a heavy-duty chain around the coil to keep it from springing to full length should the compressor tool and/or jack fail. If in doubt, play it safe and take your vehicle to a professional mechanic.

Specific coil-spring removal and replacement procedures vary depending on vehicle. (Refer to a service manual for the specific car for further information as well as for fastener torque specifications for proper re-assembly.) For example, many older cars mount the shock absorber inside the coil. If using a compressor tool, the shock must be removed so that the tool can be inserted into the spring. On the other hand, the shock is mounted away from the coil in many truck applications.

This overview is intended to help you decide whether an at-home coil swap is viable for your skill level. For many car enthusiasts, the job is virtually a no-brainer. Just beware of the potential risks involved.