Suspension springs are made from coiled steel, and are commonly coated with a protective powder coating or paint to protect them from rust and deterioration. Because their primary function is to support the weight of the vehicle's body while the vehicle is in motion, they need to be incredibly strong to withstand the constant lateral and horizontal weight shifts that the vehicle experiences during operation. Springs are under pressure at all times, even when the vehicle is parked. However, the majority of wear and tear occurs while the vehicle is in motion.
Suspension springs begin to sag and lose a tremendous amount of spring pressure as they age. Although today's springs are made to last a very long time, there are occasions when the suspension springs will wear out and need to be replaced. Anytime a spring wears out sooner than it should, the vehicle will display a few common side effects, including the vehicle leaning to one side or a rough ride.
Part 1 of 1: Replacing the suspension springs
- Combination wrench set and extensions
- Flat blade screwdriver
- Pry bar
- Replacement suspension springs (remember to replace in pairs on the same axle)
- Safety equipment including safety glasses and gloves
- Socket wrench set (verify standard or metric before starting the job)
- Work light
Step 1: Remove power from the vehicle. Before taking off any parts or beginning this job, always disconnect power from the battery. Remove the positive and negative terminals from the battery.
Step 2: Locate the springs and the strut connections. The diagram above shows the basic setup of the rear suspension on most passenger cars and SUVs. You'll notice that the spring is attached to the lower control arm and a top bushing mount on the body.
Step 3: Raise the vehicle. It's recommended to work on one wheel at a time when completing this project, but you can raise the entire rear end and place the car on jack stands. Also, chock the front tires for added safety.
- Tip: You'll have to use your jack to support the lower control arm in order to remove the springs, so make sure you place a few jack stands under the vehicle for support.
Step 4: Remove the wheel and tire. Using an impact wrench and socket or star wrench, remove the rear tire. Start with the driver side and complete the spring and shock replacement completely before moving onto the other side. Place the tire and lug nuts aside for now.
Step 5: Remove the lower control arm bolts. The lower control arm is attached to the wheel hub with one bolt that is shown in the lower left hand corner of the image above. Before you remove this bolt and nut, place your jack stand underneath the lower control arm and crank it up until you see the spring begin to slowly compress.
Once this happens, lower the jack slowly until the jack is no longer compressing the spring, then tighten the jack again for support. This is referred to as zero degree position; you'll need to remember this setting to install the new spring.
Once the jack is in position, remove the lower control bolt using an end wrench to hold the nut on the back side and an impact wrench or socket to remove the bolt. Hit the male end of the nut with a hammer to drive the bolt through the lower control arm bushing. Set the bolt and nut aside. Lower the jack to relieve tension from the lower control arm.
Step 6: Lower the control arm and remove the spring. Once the bolt has been removed, and the jack lowered, the lower control arm will easily be lowered which will permit you to remove the spring.
The top of the spring may be stuck to the upper body mount, but wiggling the spring once it is loose should clear that obstacle. Move the lower control arm down until the spring is completely loose. Remove the spring from the vehicle.
Step 7: Remove the old strut or shock. Since you're replacing the spring, it's a good idea to replace the strut or shock at the same time. Although this step is not required, it's recommended by most manufacturers and ASE certified mechanics. Refer to your service manual for the steps to complete this process.
In most cases, removing the shocks is very simple. You'll first remove the bottom bolt attached to the lower control arm, then remove the top two or three bolts attached to the upper body mount. Remove the old strut or shock and replace it with the new one.
Step 8: Install the new suspension spring. After you've removed and installed the new shock or strut, you'll be ready to install the new rear springs. To complete this step, follow these basic steps but refer to your service manual for details if needed.
Place the new spring inside the lower control arm, making sure to insert the lower spring into the same bracket on the lower control arm. Place a jack underneath the lower control arm and begin to slowly jack upward.
With one hand, support the new spring until the top has been placed firmly in the upper body mount. Raise the jack until the lower control arm is equal with the lower control arm bushing. Insert the lower control arm bolt and tighten the nut on the back side. Tighten the lower control arm bolt to the recommended torque pressure. Lower the jack and allow the spring to decompress.
Step 9: Reinstall the rear tire. Before you reinstall the rear tire, make sure to double check that the spring is straight and properly aligned inside the top and lower mounts and brackets. You should not be able to move the spring once you've attached the lower control arm. Place the tire on the hub. Insert the lug nuts or bolts into the hub. Tighten each nut or bolt slowly until they touch the hub.
Complete the tightening in a "star" pattern (refer to your service manual for instructions if needed). Torque the rear wheels to the manufacturer’s recommended torque pressure. Proceed to the other side of the vehicle and complete these steps there.
If you've read this instructional article and are not 100% confident in completing this job on your own, contact the professional and local ASE certified mechanics at YourMechanic. They have the right knowledge, experience and tools to complete a suspension springs replacement job very easily and affordably.
This article originally appeared on YourMechanic.com as How to Replace Suspension Springs and was authored by Timothy Charlet.