Support the knuckle with the jack stand to prevent dropping any suspension component aggressively. Do Not jack the suspension from the brakes. Lift it from the control arm to prevent damage.

Then remove the 17mm bolt onto the knuckle. After removing the bolt, you will need to remove the front strut from the knuckle. You may need some penetrating fluid like wd-40.

By removing it, make sure again the jack is underneath the control arm or the knuckle, you may need a rubber mallet to hammer the knuckle slightly to separate it from the front strut.

Then the strut will be released from the knuckle .

If this option doesn't work, there is also another trick to use when removing the front shock from the knuckle, there is a gap behind the knuckle, place a washer or multiple washers or even Quarters in the slot and use the 17mm bolt on the opposite side and the tighten it. This allows the gap of the knuckle to open slightly and allows the knuckle to drop with ease, allowing the front strut to be free from the knuckle. Then remove the knuckle from the front strut. You can also use a strut spreader by placing it in the gap and using a socket wrench.

Next, you'll need to open the hood and locate the three bolts that are holding the front strut. You will need a 14mm socket to remove the bolts. After removing two of them, loosen the third bolt with one hand and use the other hand to hold the strut so it doesn't fall aggressively when removing the third bolt completely. Remove the third bolt completely and remove the front strut from the vehicle.

Some coilovers setups utilize the OEM strut mount, this is where you will use the spring compressor to compress the spring from the OEM strut in order for us to transfer it to the new coilover. Place one spring compressor on one side and one spring compressor on the other side. Tighten each of them evenly until it is compressed all the way then remove the top strut mount nut with a 17mm offset end wrench and use a 6mm allen key to avoid the stud from spinning. Then remove the upper strut mount and rubber boot from the strut and transfer it to the new coilover. After you transferred the upper strut mount to the coilover , tighten the top nut and torque it to 40 ft-lbs. of torque. Note: The Bilstein coilovers come with a 19mm nut, use a 19mm offset wrench with a 5mm allen key to tighten the top strut mount.

If your coilovers have adjustable camber plates, you will need to cut the front strut tower for easier access to the bolts for adjusting your camber. Cutting the front strut tower doesn't affect the strength of the towers, however if you don't like cutting or modifying it, you may skip this step.

If you do have adjustable camber plates, you will need to use a 3 1/8' bi-metal hole saw and drill the center of the strut tower. This will give a clean cut and matches with the front bracing perfectly. You will need some sandpaper to smooth the sharp edges, clean the surface of any debris or dirt, and paint the metal that is exposed to prevent rust in the future. Make sure to use masking tape so you don't overspray the area around it.

Most coilover brands come with the necessary hardware such as three 14mm nuts. In this case, we will use the 14mm bolts from the OEM strut to install the coilovers onto the vehicle. Some coilovers will also have a mark if it is FR "Front Right" or FL "Front Left".

Place one of the coilovers onto the vehicle from the bottom and align the coilover to the three holes of the strut tower. Some coilovers have studs that will fit in one direction with the camber plates facing horizontally. Then thread the 14mm nuts or bolts by hand and then tighten them. Using a torque wrench, torque the nuts around 40 ft-lbs. of torque. 

Now let's place the coilover onto the knuckle, we recommend using white lithium grease to lubricate the bottom of the coilover and between the knuckle for easier installation. Raise the knuckle by lifting it with a jack in order to place the coilover onto the knuckle.

Adjustments will need to be made when installing the coilover on the knuckle so be patient. Most coilover brands have a mark on the back side of the coilover.

This ensures that the coilover is sitting properly on the knuckle and we can start tightening the 17mm bolt.

Tighten the 17mm bolt to 50-60 ft-lbs. of torque. 

After that, you can reinstall the end links back on the coilover , make sure to install the ABS bracket onto the end links as well

Tighten the nut to 30-40 ft-lbs. of torque.

Reinstall the brake line to the coilover mounting bracket and place the metal clip back to its place.

And finally reinstall the ABS connector to the sensor until you hear a click.

To adjust the height of the coilover , all coilover brands provide spanner wrenches to raise or lower the spring ride height. Use the spanner wrenches to loosen the lock collars by turning the bottom collar clockwise and the top collar counterclockwise. Adjust the spring to the desired height. Some coilovers require you to turn the entire shock body for height adjustments.

Once you've achieved the desired ride height, securely tighten the locking collars to prevent the adjustment from shifting during driving.

This completes installing the front coilover, let's move to the back side and install the rear spring and shock.

Rear Coilover Installation for Mazdaspeed 3

First, remove the rear end links with a 14mm wrench and a 5mm allen key to hold the stud in place. Make sure to remove it on both sides to separate the end links from the sway bar.

Once you've achieved that, you can push the sway bar downwards to free it from being connected to the control arm.

Next, use a jack to lift the control arm and compress the spring.

This will also have less stress on the 17mm bolt that needs to be removed.

After removing the 17mm bolt, lower the jack gently as the spring is compressed which there is a lot of pressure. Use a rubber mallet to gently tap the control arm.

Lower the jack again until the control arm is fully separated from the knuckle. Then remove the spring from the control arm. 

There is a 17mm bolt that is at the bottom of the rear shock. Remove it with a 17mm socket and ratchet to release the shock from the knuckle.

Also, there are two bolts that needs to be removed which are located at the top mount of the shock. Use a 12mm deep socket and ratchet to remove them. Use one hand to hold the rear shock to prevent it from letting it fall aggressively. Then remove the rear shock completely. 

Now we will need to transfer the top mount from the old shock to the new shock. Use a 12mm wrench to loosen the nut. You may need to use some pliers if the stud keeps spinning. In this case, we will be using a brand-new top mount for the rear shock.

Transfer the top mount to the new rear shock and tighten it to 15 ft-lbs. of torque. Some coilover brands require the utilization of the rubber boot.

After assembling the rear shock, place it onto the vehicle, you will need to maneuver the rear shock as it can be tricky when installing it.

Hand thread the two 12mm nuts onto the studs then tighten them to 20 ft-lbs. of torque. 

Reinstall the 17mm bottom shock mount bolt to the knuckle, some coilover brands provide washers to secure the shock from being loose. And tighten it to 60 ft-lbs. of torque.

Adjustments will need to be made by lifting the shock slightly to the top to align the holes with the knuckle. 

To adjust the ride height of the rear spring, use the spanner wrenches that's provided to loosen the collars and adjust the desired ride height.

Once you've achieved the desired ride height, securely tighten the locking collars to prevent the adjustment from shifting during driving.  

To place the rear spring onto the control arm, you will need to reuse the factory rubber pad to prevent any clunky noises. Clean the factory rubber pad and the control arm from any small rocks or debris to ensure the spring is fully seated.

Place the spring on the control arm while simultaneously placing the spring perch on top of it. Most coilover brands come with the provided rubber pads for the spring perch to prevent any clunky noises. 

Lift the control arm with a jack until the holes are aligned with the knuckle.

Then place the 17mm bolt and tighten it to 60 ft-lbs. of torque.

Reinstall the end links to the sway bar and tighten them to 35-40 ft-lbs. of torque.

To adjust the damping of the coilovers, some brands utilize a tool that can be placed at the top of the coilovers.

In this case, to adjust the desired damping, there is an adjusting knob that is mounted at the bottom of the coilover.