Lower Control Arm - Rear

This procedure covers the removal and replacement of the rear lower control arm on a 2023 Chevrolet Bolt EUV electric vehicle.

Warnings

Tools required

Parts

• Rear lower control arm × 1 — Use OEM specification
• Control arm mounting bolts × 2 — Use OEM specification
• Ball joint cotter pin × 1 — Use OEM specification

Preparation

1. Verify vehicle is in Park with parking brake engaged
2. Loosen rear wheel lug nuts while vehicle is on ground
3. Raise vehicle using floor jack at designated lift point
4. Secure vehicle on jack stands at manufacturer-specified points
5. Remove rear wheel completely
6. Spray penetrating oil on control arm bolts and ball joint nut if corrosion is present

Procedure

1. 1

   Remove ball joint cotter pin
   Locate the ball joint nut connecting the control arm to the rear knuckle. Straighten and remove the cotter pin using pliers or a cotter pin removal tool. Discard the old cotter pin as a new one must be installed during reassembly.
2. 2

   Loosen ball joint nut
   Using a 21mm socket, loosen the ball joint nut but do not remove it completely yet. Leave the nut threaded on 2-3 turns to protect the threads and prevent the knuckle from dropping suddenly when the taper is broken.
   ⚠Do not remove the nut completely until the ball joint taper is separated to prevent damage.
3. 3

   Separate ball joint from knuckle
   Position a ball joint separator tool between the control arm and knuckle. Tighten the separator tool to break the taper fit between the ball joint stud and knuckle. Once the taper is broken, remove the ball joint nut completely and lower the control arm away from the knuckle.
4. 4

   Support the knuckle assembly
   Use a bungee cord or wire to support the knuckle and strut assembly to prevent stress on the brake hose and wheel speed sensor wiring. Do not allow the assembly to hang freely.
5. 5

   Remove front control arm bolt
   Locate the front control arm mounting bolt connecting the arm to the subframe or chassis. Using a 19mm socket and wrench, remove the bolt completely. Note the orientation of any washers or spacers for reinstallation.
   ℹ️Mark or photograph the orientation of the control arm and any alignment shims before removal.
6. 6

   Remove rear control arm bolt
   Using a 19mm socket and wrench, remove the rear control arm mounting bolt connecting the arm to the subframe or chassis. The control arm should now be free to remove from the vehicle.
7. 7

   Remove control arm from vehicle
   Carefully maneuver the control arm out of the suspension area. Inspect the mounting points on the subframe for damage, corrosion, or deformation. Clean the mounting surfaces with a wire brush if necessary.
8. 8

   Prepare new control arm
   Compare the new control arm to the old unit to verify correct part. Check that all bushings are properly installed and that the ball joint moves freely without excessive play. Install new mounting bolts if supplied with the replacement arm.
9. 9

   Install control arm to subframe
   Position the new control arm into the mounting locations on the subframe. Insert the front and rear mounting bolts through the control arm bushings and subframe brackets. Thread the bolts by hand but do NOT tighten at this time. The bolts must be torqued with vehicle weight on the suspension.
   ⚠Do not torque control arm bolts until vehicle weight is on the wheels or bushing damage will occur.
10. 10

    Connect ball joint to knuckle
    Raise the control arm ball joint stud into the knuckle mounting hole. Ensure the stud is fully seated in the taper. Install the ball joint nut and tighten to specification using a torque wrench. The cotter pin hole must align - if needed, tighten slightly more (never loosen) to align the holes.
    Torque spec

    Ball Joint Nut88 Nm (65 lb-ft)
11. 11

    Install new cotter pin
    Insert a new cotter pin through the ball joint stud hole. Bend the ends of the cotter pin around the nut to secure it properly. Ensure the cotter pin cannot back out during vehicle operation.
12. 12

    Reinstall wheel and lower vehicle
    Install the rear wheel and thread lug nuts by hand. Lower the vehicle so that the full weight is on the suspension but the wheel can still rotate. This simulates normal ride height for final control arm bolt torquing.
13. 13

    Torque control arm mounting bolts
    With vehicle weight on the suspension, torque both the front and rear control arm mounting bolts to specification. This ensures the bushings are in their neutral position and will not be preloaded.
    ⚠This step is critical - torquing with suspension unloaded will cause premature bushing failure.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)
14. 14

    Final torque wheel lug nuts
    Raise the vehicle slightly, then lower completely to the ground. Torque the wheel lug nuts to specification in a star pattern to ensure even seating of the wheel.
    Torque spec

    Wheel Lug Nuts136 Nm (100 lb-ft)

Reassembly

1. Double-check that the ball joint cotter pin is properly installed and secure
2. Verify all fasteners have been tightened to specification
3. Ensure no tools or parts were left in the wheel well area

Verification

• Test drive the vehicle at low speed and verify no abnormal noises from the rear suspension
• Check for proper wheel alignment - vehicle should track straight with no pulling
• Schedule a professional four-wheel alignment as control arm replacement affects rear toe and camber settings
• After 50-100 miles, re-check torque on all fasteners

Related trouble codes on this vehicle

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