Rear Lowering Spring Install (Acura RSX / Honda Civic Si EP3)

Before raising the car, break the rear lug nuts free while the tyres still carry the vehicle's weight. Use the 19mm socket on the breaker bar with the short extension and loosen each nut only a fraction of a turn; leave them seated so the wheels stay on for now. Work in a crossing (star) sequence rather than moving around the circle, which keeps the wheel loaded evenly.

Put the transmission in first gear and let the car settle against it, then wedge a chock or wood block ahead of a front tyre to stop any roll. Lift the rear at the hook-shaped jacking point and place a jack stand under each seam-welded pinch seam on both sides. Give yourself plenty of clearance to work underneath, but do not run the jack stands out to their maximum extension.

With the rear securely on the stands, spin off the already-loosened lug nuts and pull both rear wheels. Set the wheels and their nuts aside, clear of the work area.

The strut-tower fasteners are accessed from inside the car. Fold the rear seats forward and remove the plastic strut covers behind them. On the EP3 Civic a moulded slot lets the whole cover lift straight out; on the DC5 RSX the process is fussier, requiring the carpet to be peeled back and a trim panel partly freed. Each tower has two 14mm nuts, four in total. Back them out with the 14mm socket on the 3/8 in ratchet; air tools make this quicker if available.

Move underneath to the single 17mm bolt clamping the base of each strut to the rear suspension arm. Expect it to be seized very tight. Soak it with penetrating oil and let it work in. A breaker bar on its own may not move it, so slide the jack handle over the bar for added leverage to break it loose. As the bolt releases the strut will spring outward, so keep your hands and body out of its path.

Draw each shock-and-spring unit out of the wheel well, then repeat the whole removal on the opposite corner so both assemblies are off the car and on your bench.

Separating the spring from the damper is the dangerous part of this job, because a compressed coil stores enough energy to cause serious injury or death if it escapes. A spring compressor is the correct professional tool and is strongly recommended. On these factory assemblies the coil often sits with little or no preload, which is why some choose to work by hand, but that is a genuine gamble. If you go that route, wear gloves, clear the area of people and valuables, and accept the risk.

Steady the assembly on the ground against something solid. Seat the 5mm allen key in the top of the shaft to stop it turning, then slowly back off the 14mm nut with the combination wrench. Once it is off, lift the stack apart in sequence: the nut, its spacer, the studded upper mount, the sleeve that nests inside that mount, the upper spacer, the lower retainer, and the yellow bumpstop. Wipe each part clean, keeping all solvent and oil off the shock shaft. Strip only one strut at a time and leave the other intact as a reference for part order and orientation.

The factory bumpstop is too long once the car sits lower, so cut it roughly in half with a hacksaw. Keep the larger section for reuse and discard the offcut.

Assemble the stack back up onto the lowering spring. Seat the spring so its lower coil locates in the base of the shock. Fit the large black sleeve face down so it enters both the upper mount and the top of the spring. Slide the trimmed bumpstop down the shaft, then fit the lower retainer face down until it sits flush with no gaps and draw the bumpstop back up against it. Cap them with the small black metal cover, add the lower spacer, then lower the studded upper mount onto the shaft, where it will sit slightly cocked. Finish with the upper spacer face up and the 14mm nut. Lock the shaft with the allen key and torque the nut to 22 lb-ft.

Feed each rebuilt strut back into position, guiding the two upper studs through their holes first, then checking the lower mount. The bottom hole will not line up, because the relaxed suspension does not hang low enough to meet it. Secure and torque the upper 14mm nuts to 43 lb-ft first so the strut cannot shift. Then set a deep socket on the jack saddle, raise it against the base of the strut, and compress slowly until the lower hole aligns, keeping your face and hands well clear. Slide the 17mm bolt through and torque it to 45 lb-ft. Repeat on the other side.

Mount both rear wheels and start the lug nuts by hand. Raise the car, remove the jack stands, and lower it fully to the ground before final-tightening the lugs in a star pattern. Pull the chock and reinstall the interior trim panels you removed earlier. The ride height will continue to settle over the following days and weeks as the springs bed in.

Lowering springs add negative camber, so book a professional computer alignment once the car is back on the ground. The RSX's stock rear suspension has no built-in camber adjustment, so pairing the springs with a rear camber kit lets the shop bring the geometry back into specification and avoids uneven tyre wear.