Front Lowering Spring Install (Acura RSX / Honda Civic Si)

With the car still on the ground, crack each front lug nut loose using the 1/2-inch breaker bar and 19mm socket, working in a star pattern so you never loosen two neighboring nuts back to back; leave them snug for now. Set the parking brake and wedge a chock or wood block behind a rear tire. Raise the front at the subframe jacking point and transfer the weight onto two jack stands set on the seam-weld pinch points on each side. Give yourself generous clearance underneath, but never run the stands to their maximum height. Confirm the car is stable, then spin the lug nuts off and pull both front wheels, setting them aside.

Two fasteners are far easier to break while the strut is still bolted in and held steady by the car. First, following a tip from the discussion, crack the 17mm damper-shaft nut at the top of the strut loose now: hold the shaft from turning with the 6mm Allen wrench and back the nut off about a quarter turn, but do not remove it. Second, soak the two large 22mm lower strut bolts and the 19mm tie rod nut with penetrating oil and let them sit while you clear the smaller hardware.

Two leads are clipped to the strut body near the lower bolts: the brake hose and the ABS wheel-speed sensor wire. Unbolt the brake line bracket (12mm) and the ABS sensor bracket (10mm) with the 3/8-inch ratchet, and free both so they cannot be stretched or snagged once the strut moves.

Open the hood and find the strut tower on each side, roughly above the fender well. Each top mount is retained by three 14mm nuts. Back them off with the 3/8-inch ratchet and the 14mm deep socket, and keep them together in a safe place, because they are reused on reassembly.

Before any load-bearing joint comes apart, cradle the lower control arm or hub so the steering knuckle cannot drop and drag the drive axle out of the transmission. A spare jack stand placed under the wheel studs does this well; if you have no spare stand or helper, a rope or cable slung under the spindle will hold it just as effectively. The stand bears only light pressure on the studs and will not damage the threads. Set it in place after the tie rod and lower bolts are freed.

Straighten the old cotter pin with needle-nose pliers and push it through and out; discard it. Remove the 19mm castle nut with the breaker bar and set it aside for reuse. The tapered stud will still be locked in its bore. The safest release is a two- or three-jaw puller with a flat foot rather than a pointed tip; if the tip is pointed it must sit dead-center, or it will punch into the stud and chew the threads enough to fight you on reassembly. Never drive a pickle fork in here, as it slices the rubber boot and dumps the grease. Turn the puller down slowly with the crescent wrench and keep the joint clear of your hands, because the stud lets go with a sharp snap. Some builders instead pop it with a few taps of a rubber mallet, and a couple report finishing the whole install without ever disconnecting the tie rod.

The two 22mm through-bolts are torqued to 116 lb-ft, so fit the 1/2-inch breaker bar with the 22mm socket and slide the leverage pole over the handle for reach; hold the bolt head with the 22mm wrench so it cannot spin. Loosen both a little at a time, alternating between them, until one can be worked free on its own. Keep a hand, ideally a helper's, on the rotor and knuckle to press it inward, since this is the moment the half-shaft can back out of the case. Note that some find the strut will not clear until the control arm is lowered far enough that the axle unseats; that does no harm, but re-seating it afterward takes patience and a second set of hands rocking the rotor.

With both lower bolts out and the tie rod free, ease the complete spring-and-damper unit out of the car. It is heavier than it looks and the nearby brake hose is easy to snag, so guide it clear with care and set it on the ground.

The factory coil must come off the damper. The correct and safe method uses a spring compressor; doing it by hand risks a loaded coil springing free, which can maim or kill, so treat any residual tension seriously and work in a clear area away from people and valuables. Lay the unit down and brace it. With the top nut already cracked earlier, hold the shaft with the 6mm Allen wrench and spin the 17mm nut all the way off. Lift away the upper mount with its studs, then the spring seat, the coil, and the bumpstop/dust cover. Clean the parts, keeping every trace of cleaner and oil off the polished damper shaft. Leave the second strut fully assembled beside you as a reference for part order and orientation.

Opinions differ on the dust cover / bump stop. The original writeup halves it with a hacksaw to make room for the shorter spring and keeps the larger portion; however, the spring maker's own instruction sheet trims only the bump-stop rings, and several who skipped cutting entirely report no ill effect beyond slightly reduced dust protection. Cut only if your kit calls for it. Reassemble in reverse: seat the new spring the correct way up in the lower perch (check the intact strut to confirm which end goes down), add the bump stop, then press the metal spring seat into its grooves until it snaps home. Fit the upper mount with its 14mm studs, which will sit slightly cocked until the spring is loaded, and thread the 17mm nut on, snugging it with the Allen wrench holding the shaft. Final torque comes after reinstallation.

Lift the assembly back up into the tower. The three top studs are unevenly spaced and seat only one way, so line them up against the tower holes and start the three 14mm nuts by hand. Have a helper steady the knuckle again so the axle stays home as you swing it in. Reinsert the two 22mm lower bolts loosely, then reconnect the ABS and brake-line brackets. Drop the tie rod stud back into its bore and start its nut. When aligning the top mount, rotate the damper base so the outboard delta mark ("L" on the left, "R" on the right) faces outward; heed a correction from the thread, though: line the large triangle up with the white paint mark, not with the small triangle.

Tighten in a sensible sequence to the listed values. Lower strut bolts: 116 lb-ft, worked up in stages alternating upper and lower while holding the far side with the 22mm wrench. Tie rod end nut: 32 lb-ft, then fit a fresh cotter pin and bend it to mirror the one you pulled. Upper strut mount nuts (14mm): 33 lb-ft. Damper-shaft nut (17mm): 33 lb-ft. Brake line bracket (12mm): 16 lb-ft. ABS sensor bracket (10mm): 7.2 lb-ft. Repeat the whole procedure on the opposite corner. Refit the wheels and start the lugs, lift the car, pull the stands, and lower it slowly. Torque the lug nuts, remove the chock, and inspect the front suspension. Expect the ride height to settle a little further over the following days and weeks.