Strut assemblies, which integrate the shock absorber and coil spring into one unit, are an integral part of a vehicle’s suspension system. If you’re looking to replace or service the strut or coil spring, you’ll need to compress the spring first. This task requires the use of a spring compressor, and while it may seem straightforward, it can be dangerous if not done correctly. This article will guide you through the step-by-step process of safely and effectively using a spring compressor on struts.

Safety First: Before we dive into the steps, remember that coil springs are under immense pressure. A sudden release of this pressure can result in serious injury. Always wear safety glasses, gloves, and use tools that are in good condition.

Materials and Tools You’ll Need:

Spring compressor
Safety glasses
Gloves
Ratchet and socket set
Wrench set
Penetrating oil
Jack and Jack stands

Prepare the Vehicle:

1. Parking:

Choose a flat and even area, free from any slopes or potential disturbances. This is critical because any inclination or unevenness can pose a risk when jacking up the vehicle. The stability of the vehicle on a flat surface ensures that it won’t roll or shift unexpectedly.

2. Jacking up the Vehicle:

Before lifting, engage the parking brake for added safety.
Position the jack under the vehicle’s recommended jacking points. These can be located using your vehicle’s owner manual. Placing the jack in the wrong spot can damage the vehicle or cause it to lift unevenly.
Begin to lift the vehicle slowly, ensuring the jack remains stable as it raises the car.
Once the vehicle is lifted to the desired height, slide the jack stands underneath, positioning them again at the manufacturer’s recommended points, ensuring they’re locked in place.
Gently lower the vehicle onto the jack stands and ensure it sits securely. Shake the vehicle slightly to confirm stability before proceeding.

Remove the Strut Assembly:

Consultation of Service Manual:

Before diving into the procedure, always consult your vehicle’s specific service manual. This manual will have manufacturer-specific guidelines and instructions to help you navigate the process without causing any damage.

Wheel Removal:

Using a lug wrench or an impact gun, remove the lug nuts from the wheel.
Carefully take off the wheel, setting it aside in a location where it won’t roll away or pose a tripping hazard.

Disconnecting Sway Bar Link:

The sway bar link is a component that connects the sway bar to the suspension. It helps control the vehicle’s body roll during turns.
Using the appropriate wrench, remove the nut connecting the sway bar link to the strut. Some sway bar links might have a Torx or Allen slot on one end to prevent the stud from spinning. Make sure you hold onto that end while loosening the nut.

Brake Line Disconnection:

The brake line is typically attached to the strut using clips or small bolts.
Carefully disconnect the brake line, ensuring you don’t pull, stretch, or damage the line. It’s vital not to strain the brake line as this can lead to leaks or compromised braking performance.

Removing Strut Assembly Bolts:

There will be several large bolts securing the strut assembly to the vehicle. These bolts connect the strut to the steering knuckle.
Using a socket and ratchet or wrench, remove these bolts. Some might be on very tight, so penetrating oil or a breaker bar might be useful to break the initial tension.
Once the bolts are removed, you should be able to free the strut assembly from the vehicle. Some wiggling or maneuvering might be necessary.

Remember, while the steps above are general guidelines, the specific processes can vary depending on your vehicle’s make, model, and year. Always use the service manual as your primary reference.

Set up the Spring Compressor:

There are various types of spring compressors. The most common type for DIYers is the clamp-style that has two pieces which clamp onto opposite sides of the spring. Ensure that you understand your tool’s specifics. Apply a little penetrating oil on the strut’s spring to help the compressor grip better.

Compress the Spring:

Attach the spring compressor on opposite sides of the spring. Make sure they’re as opposite as possible to evenly distribute the tension.
Slowly start tightening the compressor. Alternate between the two sides, ensuring that the spring compresses evenly. This prevents the spring from binding or slipping out of the compressor.
Continue compressing until there’s enough space to safely remove the strut mount or top hat.

Remove or Replace the Strut or Spring

Once the spring is safely compressed, you can remove the strut mount nut, typically found at the top of the strut assembly.
After removing the nut, you can slide off the mount, followed by the spring itself.
If you’re replacing the strut, simply slide the new strut into the compressed spring, making sure it’s positioned correctly. If you’re replacing the spring, release the compressor from the old spring and then use it to compress the new spring before installation.

Reassemble the Strut Assembly

Once the new part(s) are in place, reinstall the strut mount or top hat.
Tighten the strut mount nut. Make sure it’s tight but do not overtighten as this can damage the strut or mount.
Carefully and slowly start releasing the spring compressor, alternating between the two sides, until the spring expands to its natural state.

Reinstall the Strut Assembly on the Vehicle

Now that the strut assembly is reassembled, you can reinstall it on the vehicle. This process is essentially the reverse of removal. Reconnect any sway bars, brake lines, and other components you might have disconnected.
Once the strut is securely in place, you can replace the wheel.

Final Check

After the meticulous process of preparing the vehicle, using a spring compressor, and reinstalling the strut assembly, it’s imperative to conduct a comprehensive final check. This step ensures that all components have been fitted correctly and that the vehicle is safe for operation.

To start, visually inspect the area you worked on. Look for any tools or components left behind. Everything should be back in its proper place, and there shouldn’t be any stray nuts, bolts, or other small parts. Such overlooked items can lead to significant mechanical problems or pose road hazards.

Next, check the tightness of all connections and bolts. Using your ratchet and socket set, go over each bolt to confirm it’s tightened to the specifications mentioned in the vehicle’s service manual. Over-tightening can damage parts, while under-tightening can lead to components coming loose during driving, both scenarios compromising safety.

After the visual and manual checks, lower the vehicle off the jack stands. Ensure that it’s resting evenly on the ground, with no parts touching the floor inappropriately. Once on the ground, apply pressure to the vehicle’s front end, pushing down a few times to allow the suspension to settle and to ensure there’s no unusual movement or sounds.

Lastly, perform a test drive in a safe area, free from heavy traffic. During the drive, pay attention to how the vehicle responds. Any unusual noises, vibrations, or changes in handling should be immediately noted. If any abnormalities are detected, it’s advisable to re-inspect the work or consult with a professional mechanic.

Using a spring compressor on struts is a task that demands patience, carefulness, and respect for the immense force stored in the spring. Always prioritize safety, ensure you’re using the right tools, and don’t rush the process. If at any point you feel uncomfortable or unsure, it’s always best to consult a professional or take your vehicle to a trusted mechanic.

How to Use a Spring Compressor on Struts?