How to Install Lowering Springs on a 2015-2023 Mustang

How to Install Lowering Springs on a 2015-2023 Mustang

Last Updated March 28, 2024 | Bill Tumas
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Mustang lowering springs are an affordable way to lower your Mustang without committing to a full set of coilovers. They're also less expensive than coilovers, so they're great for budget-minded enthusiasts who still want that lowered look without breaking the bank.

Be sure to check out our guide on picking the best lowering springs for your driving style before you start.

S550 Mustang Lowering Springs Install

Today, we're going to show you how to install a set of lowering springs along with a pair of caster camber plates on your 2015 Mustang GT. While we're using a 2015 GT in this installation, the process is largely the same for your 2016-2023 Mustangs.

We also went with a set of ACCELATEC lowering springs for our install. These springs will lower the front of your Mustang 1.5 inches, and the back 1 inch to give your Mustang a nice custom look.

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Installation Time: ~2-3 hours

Difficulty: Moderate

Tools Needed:

  • Lift and Pole Jack or Jack and Jack Stands
  • 1/2" Ratchet
  • 13mm Socket
  • 18mm Socket
  • 3/4" Socket
  • 13/16" Socket
  • 15/16" Deep Socket
  • 21mm Socket
  • Short Extension
  • 15mm Wrench
  • 17mm Wrench
  • 1/2" Impact Gun
  • Panel Removal Tool
  • Hammer
  • Spring Compressor

Step 1: Jack Up Your Mustang

Jack your S550 up off the ground and remove all four wheels using a 21mm deep socket.

Lifted Mustang without wheels or tires

Step 2: Disconnect Front Sway Bar

With your front wheel off, disconnect the sway bar from the front strut. To do that, you'll need to grab a wrench and put it on the back side to hold the sway bar while you remove the nut. Once the nut is off, move the end link.

Closeup of front strut and sway bar

Step 3: Disconnect Brake Caliper

With the end link out of the way, it's time to disconnect the caliper. On the back of the caliper, you'll find two 15mm bolts holding the caliper to the spindle. Once you remove those bolts, you'll be able to slide the caliper off the rotor and set it aside. Be sure not to let the caliper hang by the brake hose.

Mechanic disconnecting the front brake caliper

Step 4: Remove ABS Lines and Brake Rotor

Once the caliper is set aside, remove the two ABS line connections from the strut using the panel removal tool. You can then remove the rotor.

Mechanic carefully removing the ABS line

Note: Removal of the rotor isn't mandatory, but it's recommended. If you leave the rotor on the spindle, just put a lug nut back on so it doesn't fall off the spindle after the strut is removed.

Step 5: Loosen Nuts on Strut/Spindle Bolts

Next, begin to remove the two bolts holding the spindle to the strut. When using your impact to remove these nuts, be sure to leave the nuts just at the end of the bolt. You'll have to hammer these bolts out since they’re splined and pressed into the spindle. Leaving the nut on the end allows for more surface area to hit so you don't mushroom the end of the bolt.

Mechanic pointing at a bolt that is mostly unscrewed, with nut still attached

Step 6: Hammer Strut/Spindle Bolts Out

Hammer the bolts out and be careful to make sure the nut is on the end of the bolt as you're hammering. Once you're past the splined portion of the bolt, you can remove the nut. You should be able to pull the bolts out by hand.

A closeup of the splined portion of a bolt

Note: If this is the first time these bolts have been removed, they can be stubborn. You may have to put some serious force to get them to budge, but they’ll eventually come out.

Step 7: Separate Strut from Spindle

Remove the nuts and jiggle the spindle to slide the two strut bolts out. You can then let the spindle hang.

A closeup of the front wheel spindle hanging

Step 8: Remove Strut Tower Nuts

Now, move to the engine bay. The strut is held to the strut tower by three nuts. Remove the first two. When you're ready to remove the last one, make sure you're holding the strut from the bottom or it will fall off.

A closeup of a strut tower bolt being removed

Step 9: Compress Spring

Compress the spring using a spring compressor. You’ll know that you compressed the spring enough when the rubber at the top begins to separate from the mount.

Safety Note: This is potentially the most dangerous part of this installation. When the spring is on the strut, it's under hundreds of pounds of pressure. Be sure to get a high-quality spring compressor like the one we are using for our installation.

A compressed spring in a spring compressor

Step 10: Remove Strut Mount Nut

Remove the nut on the top once the spring is fully compressed and the pressure is off the strut mount. While removing the strut mount nut, be sure to hold the mount so it doesn't spin.

A mechanic removing the nut from the top of the strut mount

Step 11: Remove Strut from Spring

Once the mount is off, pull the strut out from the spring. At this point, you’ll want to carefully decompress the factory spring.

The decompressed spring in a spring compressor

Step 12: Remove Factory Dust Boot and Bump Stop

Remove the dust boot and factory bump stop from the strut.

Mechanic removing the dust boot from the strut

Step 13: Install New Bump Stop

Slide the new supplied bump stop into the new dust boot and slide them onto the strut.

Mechanic sliding new the bump stop into place

Step 14: Install Camber Plates (Optional)

Installing new caster camber plates at this time will allow you to dial in your alignment after the new springs settle. They replace the top of the strut mount. If you’re not planning to install new caster camber plates, skip to Step 16.

To install them, you'll want to separate the top of the factory strut mount and replace it with the new caster camber plate. Line the stud plates up with the bearing plate assemblies as shown below. The horizontal notch in the stud plate should be parallel with the horizontal edge of the bearing plates.

Mechanic lining up the caster camber plates with the bearing plates

Step 15: Align Caster Camber Plates (Optional)

Align the new caster camber plate on top of the rubber insulator until it slides into place. The caster camber plate should be able to spin cleanly within the rubber insulator.

Newly assembled strut mount

Step 16: Slide the New Spring Onto the Strut Assembly

Slide the new spring into the spring compressor and compress it. Then, slide it into the strut assembly.

Mechanic compressing the spring in a spring compressor

Step 17: Mount Caster Camber Plate

After making sure the spring is seated properly in the bottom spring isolator, grab your new caster camber plate and mount and slide it over the top. Be sure that the rubber isolator on the mount is seated correctly around the top of the spring and tighten it down.

Mechanic adding the caster camber plate mount

Tech Tip: You'll know when the strut mount is completely tightened when the mount or strut spins as you're tightening it. Grab the mount with a towel or cloth while you're tightening the nut so it doesn't jolt when you're holding it.

Step 18: Decompress Spring/Strut Assembly

Once the top nut is tightened, make sure that the spring is seated properly in both rubber isolators. Then, decompress the spring to complete your new spring/strut assembly.

Mechanic decompressing the spring

Step 19: Re-Install Spring/Strut Assembly

Make sure the "ear" of your caster camber plates are facing the outside of the car when sliding up the strut tower.

Mechanic showing the camera the correct orientation for caster camber plates

Note: If you're still using the factory strut mounts on your installation, there is no specific orientation the mount needs to be in when it's installed in the strut tower.

Step 20: Tighten Strut

Next, slide the assembly from the bottom of the car into the three bolt holes in the strut tower. Use the top plate, washers and nuts from your kit and hand tighten them into place.

Mechanic connecting the new strut to the strut tower

Step 21: Connect Spindle to Strut

Connect the spindle with the bottom of the strut. Before doing this, make sure your ABS line is where it's supposed to be. Slide each bolt through and put a nut on each end of the bolt. Remember, these are splined bolts so give them a tap with the hammer to start them off. Then, tighten the nuts to pull the bolts completely tight.

Mechanic showing the bolts in the correct location and ready to be tightened

Step 22: Reinstall Rotor and Caliper

After the strut to spindle bolts and nuts are completely tightened, reinstall the rotor and caliper.

Mechanic reinstalling the brake rotor

Tech Tip: When you put the rotor back on, put one lug nut on to keep the rotor still while you reinstall the caliper.

Step 23: Reconnect Sway Bar End Link

Make sure your ABS lines are all back in place and reconnect the sway bar end link.

Mechanic showing the camera where the sway bar end link is

Step 24: Torque Strut Tower Nuts

Once the sway bar end link is tightened, move to the engine bay. Torque the three strut tower nuts to 46 ft/lbs, or whatever the instructions for your specific springs recommend.

Three strut tower nuts being torqued to spec by a mechanic

Step 25: Repeat Process on Opposite Side

Repeat the entire process so far on the other side and then move to the rear suspension.

Mechanic standing under the rear suspension of a Mustang

Step 26: Unbolt Brake Line Bracket

First, pop out the ABS line to give yourself some more room. Then, unbolt the brake line bracket.

Mechanic popping out the rear ABS line

Step 27: Remove Rear Strut Mount Bolts

Next, you'll want to remove the two rear strut mount bolts.

Mechanic using a drill to remove the rear strut mount bolts

Step 28: Remove Mount from Strut

Pop the black cover off by rocking it back and forth. Then, remove the single strut nut on the top and remove the mount from the strut.

Mechanic removing the mount from the strut

Step 29: Remove Rear Dust Boot and Bump Stop

Remove the rear dust boot and bump stop from the strut. Note that there is a little ridge at the top of the strut that will take some strength to get the bump stop over.

Mechanic pulling the rear dust boot off of the strut

Step 30: Separate Factory Bump Stop

Once you have it off, separate the factory bump stop from the boot by pushing it down inside.

Mechanic pushing the bump stop free from the boot

Step 31: Reinstall New Bump Stop and Dust Boot

Slide the new bump stop into the dust boot from the bottom as shown below. Then, reinstall it on the rear shock with the bump stop at the top.

Mechanic sliding the new bump stop into the boot

Step 32: Support Rear Subframe

Use your jack and support the rear subframe.

Mechanic using a pole jack to support the rear end of a Mustang

Step 33: Loosen Subframe Bracket Bolts

Loosen the two bolts on the bracket connecting the rear subframe to the body but leave them partially screwed in as it does not need to be removed.

Removing the bracket that connects the rear subframe

Step 34: Remove Subframe Bolts

Remove both subframe bolts on the side you're working on.

Mechanic removing a rear subframe bolt

Step 35: Lower Rear Subframe

Slowly lower the rear subframe until there is no more tension on the spring.

Mechanic using a pole jack to lower the subframe

Step 36: Remove the Spring

Pull down on the suspension and use your other hand to pull the spring out of the subframe.

Mechanic removing the spring from the subframe

Step 37: Transfer Insulator

Remove the insulator from the factory spring and transfer it over to the top of your new spring.

Mechanic placing the insulator on top of the new spring

Step 38: Install New Spring

Install the new spring the same way you removed your factory one. Make sure the end of the bottom coil matches up with the stop in the bottom of the bucket on your rear subframe.

The spring has been reinserted

Step 39: Raise Subframe

Once the spring is in place, raise the rear subframe into place using the jack. Make sure the spring seats properly as you're raising the subframe up.

Mechanic using a pole jack to raise the rear subframe

Step 40: Tighten Bracket Into Place

Put both subframe bolts back into place and hand-tighten them. Then, tighten the bracket back into place.

Mechanic tightening the subframe bracket with a socket wrench

Step 41: Tighten Subframe Bolts

Fully tighten both subframe bolts with an impact to ensure they won't come loose.

Mechanic tightening the subframe bolts with an impact

Step 42: Reinstall Mount on Shock

With all the subframe bolts back in place and the spring installed, lower the jack and move to the rear shock. Reinstall the mount on the shock and then put the black cap back on.

Mechanic reinstalling the mount on the rear shock

Step 43: Reinstall Shock

With the shock and mount back together, re-install it on the car. Slide the mount under the tabs on the body to hold it in place. Hand tighten the bolts to get them started, then fully tighten.

Mechanic hand tightening the bolts on the mount by hand

Step 44: Reinstall ABS and Brake Lines

Finally, re-install the ABS line and brake line bracket you removed originally.

Mechanic reinstalling the ABS line

Step 45: Repeat Process on Other Side

Repeat the process for the rear suspension on the other side and your installation is finished!

Lowered black S550 Mustang

Upgrade the Rest of Your S550's Suspension

Please keep in mind that this guide is a tool to help you install the parts on your vehicle. If you don't feel confident in performing this installation on your own, have a professional install the parts for you.

Check out our selection of other S550 front Mustang suspension mods to get better performance out of your ride.

This article was researched, written, edited, and reviewed following the steps outlined in our editorial process. Learn more about CJ's editorial standards and guidelines.