S650 Mustang Lowering Spring Install Instructions

S650 Mustang Lowering Spring Install Instructions

Last Updated March 21, 2024 | Bill Tumas

With the release of the S650 Mustang generation, enthusiasts everywhere are looking for cost-effective ways to customize their new rides. Mustang lowering springs are an affordable way to give your S650 a more appealing stance without committing to a full set of coilovers. They're less expensive than coilovers, making them great for budget-minded enthusiasts who still want that lowered look without breaking the bank.

Follow the steps below for a complete guide to installing aftermarket lowering springs on your S650 Mustang. You'll be back on the road in no time with a new, lowered stance for your ride.

S650 Mustang Lowering Springs Install

For this install, we went with a set of ACCELATEC lowering springs for our 2024 Mustang base model. These lowering springs are direct replacements for your S650 Mustang's stock springs and fit with your factory shocks and struts. They lower your S650 Mustang 1.5 inches and give a custom stance to your pony car.

Before you begin the installation, you'll need to jack up your S650 Mustang and remove the wheels. Be sure you have easy and safe access to the bottom of the suspension system.

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Installation Time: 3 hours

Difficulty: Moderate

Tools Needed:

  • 3/8" Ratchet
  • 7/16" Ratchet
  • Torque Wrench
  • 13mm Socket
  • 15mm Socket
  • 18mm Socket
  • 21mm Socket
  • 29mm Socket
  • 13/16” Socket
  • 17mm Socket
  • Clip Removal Tool
  • Hammer

Step 1: Remove Front Strut Tower Bolts

Pop your Mustang's hood and locate the three bolts at the top of the strut tower. Remove two of the bolts and loosen the third bolt, but do not remove it so the strut tower stays in position.

Removing front strut tower bolts from an S650 Mustang

Step 2: Disconnect Brake Caliper and Rotor

Head to the wheel well beneath the strut tower and loosen the two 15mm bolts holding the brake caliper to the spindle. Remove the two bolts starting with the top bolt. Slide the caliper off the rotor and set it aside. Once the caliper is removed, slide off the rotor and set it aside as well.

Disconnecting the brake calipers and rotors on an S650 Mustang

Step 3: Remove Sway Bar End Link

Locate the sway bar end link at the bottom of the strut tower. Place a wrench on the back side of the end link connection to hold it in place and remove the nut on the front. With the nut removed, slide out the end link bolt. You may need to push down on the sway bar to loosen it.

Removing the sway bar end link on an S650 Mustang

Step 4: Loosen Nuts on Strut/Spindle Bolts

Start removing the two bolts that connect the spindle to the strut. Use an impact wrench to loosen the nuts on these bolts, but don't fully remove them. These bolts are splined, so you'll need to hammer them out once the nuts are loosened.

Disconnecting sway bar end bolts on an S650 Mustang

Pro Tip: Leaving the nuts still partially attached provides more surface area to strike with the hammer. This will help prevent deforming or "mushrooming" the end of the bolt.

Step 5: Hammer Strut/Spindle Bolts Out

Hammer out the strut/spindle bolt, but 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 should be able to remove the nut and pull the bolts out by hand.

Hammering out spindle bolts on an S650 Mustang

Step 6: Remove Strut Tower Assembly

Move to the engine bay. Remove the last hand-tight strut tower bolt from step 1, but make sure you're holding the strut from the bottom so it doesn't fall.

removing the strut tower assembly on an S650 Mustang

Step 7: Compress Factory Spring

Connect a spring compressor to the spring and tighten the compressor. You'll know that you compressed the spring enough when the rubber boot at the top of the strut tower begins to separate from the mount.

Safety Note: The spring is under extreme tension when mounted on the strut, with hundreds of pounds of force compressing the spring. Use a heavy-duty, professional-grade spring compressor, like the one demonstrated here, and read the manufacturer's instructions carefully to avoid any unsafe situations when disassembling the strut.

Compressing the springs on an S650 Mustang

Step 8: Remove Strut Mount Nut

Use an impact wrench to remove the nut on the top of the strut tower once the spring is fully compressed and the pressure is off the strut mount. Grip the strut mount support with a pair of pliers and a rag so the assembly doesn't spin.

Slide the strut tower assembly out from inside the spring.

Removing the strut mount nut on an S650 Mustang

Step 9: Decompress Factory Spring

Carefully decompress the factory spring using the spring compressor.

Decompressing the factory spring on an S650 Mustang

Step 10: Install New Bump Stop

Remove the dust boot and factory bump stop from the strut. Install the new bump stop in the same position as the factory part and reinstall the dust boot.

Installing new bump stop on an S650 Mustang strut tower

Step 11: Slide the New Spring Onto the Strut Assembly

Use the spring compressor to compress the new lowering spring. Once the spring is compressed, slide the strut assembly inside the spring. Make sure the insulator is lined up with the end of the coil and the wording is facing the correct direction so the assembly is not upside down.

With the spring still compressed, reinstall the strut tower nut at the top of the assembly.

Sliding a lowering spring into an S650 Mustang strut tower

Step 12: Decompress Spring/Strut Assembly

Make sure that the spring is seated properly in both rubber insulators. Then, decompress the spring to complete your new spring/strut assembly.

Decompressing a lowering spring on an S650 Mustang strut tower

Step 13: Reinstall Spring/Strut Assembly

Slide the strut tower assembly back into the factory position and hand tighten the top three bolts to hold the assembly in place.

Reinstalling the strut assembly on an S650 Mustang

Step 14: Connect Spindle to Strut

Insert the splined bolts through the mounting holes and add a nut to each end. Since the bolts are splined, use a hammer to lightly tap them into place before tightening to align the splines. Once aligned, use the nuts on either end to tighten the bolts down using a torque wrench to the factory recommendation of 185 lb/ft.

Reconnecting the spindle to the strut tower on an S650 Mustang

Step 15: Tighten Strut Mount Bolts

Torque down the hand-tightened bolts on the top of the strut tower to 46 lb/ft.

Tightening strut tower bolts on an S650 Mustang

Step 16: Reconnect Sway Bar End Link

Reconnect the ABS lines and reattach the sway bar end link. Torque down the bolts to 76 lb/ft.

Reconnecting the sway bar end link on an S650 Mustang

Step 17: Reinstall Brake Rotor and Caliper

Slide the rotor back onto the factory studs and hold it in position with a lug nut. Reattach the caliper and hand tighten the two bolts on the back. Tighten down the caliper spindle bolt connection to an 85 lb/ft torque spec.

Reinstalling the brake rotors and calipers on an S650 Mustang

Pro Tip: Hand-tighten one lug nut when you put the rotor back on to keep the rotor still while you reinstall the caliper.

Step 18: Repeat Process on Opposite Side

Repeat steps 1-17 on the opposite front side of your Mustang. Then move to the rear suspension.

Step 19: Unbolt Brake Line Bracket and Shock Mounts

Pop out the ABS line to give yourself some more room. Then, unbolt the brake line bracket and the two upper mounts for the shock.

Unbolting the brake line brackets on an S650 Mustang

Step 20: Remove Rear Strut Mount Bolts

Remove the two rear strut mount bolts beneath the strut assembly. Make sure you have enough room beneath your Mustang to operate safely.

Removing the rear strut mount bolts on an S650 Mustang

Step 21: Support Rear Subframe

Insert a jack beneath the rear subframe to support it before removing the subframe bracket bolts.

Supporting the rear subframe of an S650 Mustang with a jack

Step 22: Loosen Subframe Bracket Bolts

Remove the two bracket bolts connecting the rear subframe to the body.

Loosening the subframe bracket bolts on an S650 Mustang

Step 23: Remove Rear Subframe Bolts

Remove the blue rear subframe bolt. This will disconnect the subframe, so make sure the frame is well-supported with a jack before removing the bolt.

Removing the rear subframe bolts on an S650 Mustang

Step 24: Lower Rear Subframe

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

Lowering the rear subframe of an S650 Mustang

Step 25: Remove the Spring

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

Removing the rear stock spring on an S650 Mustang

Step 26: Transfer Insulator

Remove the insulator from the factory spring and transfer it over to the top of your new lowering spring. The rubber stop on the insulator should press up against the end of the coil. Make sure the lettering is facing up, so the spring is not upside down.

Transferring insulator on an S650 Mustang lowering spring

Step 27: Install New Lowering Spring

Insert the lowering spring into the factory position. Make sure the end of the bottom coil matches up with the stop in the pocket of the lower control arm.

Installing new rear lowering spring on an S650 Mustang

Step 28: Raise Subframe

With the spring in position, raise the rear subframe using the jack. Make sure the spring seats properly at the connecting point as you raise the subframe.

Raising the rear subframe on an S650 Mustang

Step 29: Tighten Rear Subframe Bracket Bolts

Put both subframe bolts back into place and hand-tighten them. Then, tighten the subframe bracket bolts to a torque spec of 41 lb/ft.

Tightening the rear subframe bracket bolts on an S650 Mustang

Step 30: Tighten Subframe Bolts

Hand-tighten the larger subframe bolt, then tighten it down to 129 lb/ft of torque.

Tightening the rear subframe bolts on an S650 Mustang

Step 31: Disassemble Factory Shock

Pop off the rubber cap on the factory shock, then unscrew the nut at the top of the shock assembly.

Disassembling the factory shock tower on an S650 Mustang

Step 32: Install Shorter Bump Stop

Remove the dust boot and the factory bump stop from the shock assembly. Replace the stock bump stop with the smaller option from your lowering spring kit. Reseat the new bump stop, reassemble the shock, and retighten the nut at the top of the shock assembly. Remember to add the rubber cap back on the top of the shock.

Installing a shorter bump stop on an S650 Mustang

Step 33: Reinstall Shock

Re-install the shock assembly on the car. Slide the mount into position and reattach the top and bottom bolts. Hand-tighten the bolts to get them started. Then, torque down the shock assembly bolts to 66 lb/ft on the top bolts and 35 lb/ft on the bottom bolts.

Reinstalling rear shock assembly on an S650 Mustang

Step 34: Reinstall ABS and Brake Lines

Re-install the brake line bracket and reinsert the clip for the ABS line.

Reattaching S650 Mustang brake line

Step 35: Repeat Process on Other Side

Repeat steps 19-34 for the rear suspension on the other side and your installation is finished!

Upgrade the Rest of Your S650's Suspension

New lowering springs give your S650 Mustang a more aggressive stance that transforms the look of your vehicle for a custom edge. If you want to go even further, add a new set of wheels and tires to your S650 to really complete the look. The S650 Mustang's aftermarket is growing every day with awesome new ways to upgrade and customize your suspension even further. Check out our list of the best S650 Mustang mods if you're looking for other ways to improve the performance of your ride.

Whether you're prepping for the track or improving your daily driver, we have the S650 suspension parts you need to take your Mustang to the next level. Check out our wide variety of 2024 Mustang suspension parts and get started on improving your suspension's capabilities today!

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.