Table of Contents
Getting Ready to Tackle the Lower Control Arm
Replacing a lower control arm is a common suspension repair that restores steering precision and ride comfort. Before you lift the vehicle, gather the right tools: a 21‑mm socket for the hubcap, 17‑mm and 19‑mm sockets for various bolts, a 22‑mm wrench for the front control arm, a 30‑mm socket for the axle nut, and a torque wrench for the final tightening steps. Keep a jack, jack stands, a pry bar, a hammer, and a punch handy. Safety first: secure the car on a flat surface, block the rear wheels, and use jack stands to support the vehicle once it’s lifted.
Removing the Old Control Arm
Start by removing the wheel: take off the hubcap, then use the 21‑mm socket to loosen the five lug nuts. Lift the wheel off the hub and set it aside. Next, address the outer tie‑rod: bend the cotter pin up and out of the way, then remove the nut with a 17‑mm socket. Tap the tie‑rod knuckle with a hammer to break the tension, and remove the two caliper bolts with the same socket. Hang the caliper from the strut using a hook so the brake hose stays slack.
Remove the rotor and then the axle nut with the 30‑mm socket. Push the axle to confirm it moves freely; if it’s stuck, use a punch and hammer to free it. Loosen the four wheel‑bearing bolts with a 17‑mm socket, tap around the bearing, and pull it out. Bend the cotter pin straight for the lower ball‑joint nut, then use cutters to remove it. Loosen the lower ball‑joint nut with a 19‑mm socket, break the tension with a hammer, and pull the lower control arm down to separate the ball joint from the knuckle.
Installing the New Control Arm
With the vehicle jacked up, locate the front control‑arm bolt. Use a 22‑mm wrench to hold the top nut while a 22‑mm socket removes the bolt. Remove the bolt and the nut, then loosen the two 17‑mm bolts that secure the bracket. Do not fully remove the middle bolt; just loosen it enough to allow adjustments. Repeat the process on the opposite side, removing the two 17‑mm bolts that hold the brace. Pry between the brace and the transmission pan with a pry bar, then remove the lower control‑arm bolt.
Install the new lower control arm by first attaching the rear bushing, then the front bushing. Align the bolt hole with the control arm’s front mounting point and pull down to create space. Start the bolt by hand, then use a large pick to line up the rear bushing. Tighten the bolt to 127 ft‑lb, and if a torque wrench isn’t available, tighten as far as possible. Use a 22‑mm wrench to hold the nut while you torque the bolt to 172 ft‑lb. Repeat the same procedure on the other side, ensuring all bolts are snug and torqued to the specified values.
Reassembling the Wheel and Final Checks
Lower the vehicle and remove the jack. Start the wheel‑bearing bolts at the back of the knuckle, then tighten them in a cross pattern to 71 ft‑lb. Install the lower ball‑joint nut and the outer tie‑rod end, starting the nut by hand and tightening to 98 ft‑lb for the ball joint and 36 ft‑lb for the tie‑rod. Install the cotter pin, bend the tabs over, and secure the axle nut to 159 ft‑lb. Use a hammer and punch to stake the axle nut in place.
Reinstall the rotor, pull the caliper off the hook, and tighten the caliper bolts to 79 ft‑lb. Tighten the outer tie‑rod end to 36 ft‑lb. Lower the vehicle back to the ground, install the wheel, and tighten the lug nuts in a star pattern to 79 ft‑lb. Finally, replace the hubcap.
After the Repair
Once the new control arm is in place and all fasteners are torqued to specification, the vehicle should sit at the correct ride height. Because the suspension geometry has changed, it’s essential to have the car aligned at a professional shop. Proper alignment ensures even tire wear and restores the steering feel you expect from a well‑maintained Scion xD.
By following these steps carefully, you’ll replace the lower control arm with confidence, knowing that each bolt and nut is tightened to the manufacturer’s recommended torque. This thorough approach keeps the suspension safe and reliable for many miles of driving.