Radius Arm

This procedure covers the removal and replacement of the front radius arm (lower control arm) on the 2023 Chevrolet Bolt EUV, including disconnection of the ball joint and control arm mounting points.

Warnings

Tools required

Parts

• Radius arm (lower control arm) × 1 — Use OEM specification
• Ball joint cotter pin × 1 — New cotter pin required
• Control arm mounting bolts (if corroded) × 2 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks behind rear wheels
3. Open hood and disconnect 12V auxiliary battery negative terminal
4. Loosen wheel lug nuts on the side being serviced while vehicle is on ground
5. Raise front of vehicle with floor jack at designated lift point
6. Support vehicle with jack stands under frame rails
7. Remove wheel completely

Procedure

1. 1

   Remove ball joint cotter pin
   Locate the ball joint castle nut where the radius arm connects to the steering knuckle. Straighten and remove the cotter pin using pliers. Discard the old cotter pin as a new one must be installed.
2. 2

   Loosen ball joint castle nut
   Using a socket and breaker bar, loosen the ball joint castle nut but do not remove it completely yet. Leave the nut threaded on a few turns to protect the threads and prevent sudden separation.
3. 3

   Separate ball joint from knuckle
   Position a ball joint separator tool between the radius arm and steering knuckle. Apply pressure using the tool to separate the ball joint taper from the knuckle. Once separated, remove the castle nut completely. If using a pickle fork, be aware this may damage the ball joint boot.
   ⚠The ball joint may separate suddenly. Keep hands and body clear of pinch points.
4. 4

   Support the radius arm
   Place a floor jack or support under the outer end of the radius arm to prevent it from dropping when the mounting bolts are removed. This prevents stress on brake lines and ABS sensors.
5. 5

   Remove front control arm mounting bolt
   Locate the front mounting bolt that secures the radius arm to the front subframe. This bolt passes through the front bushing. Use a socket and breaker bar to remove the bolt completely. Note the orientation of any washers or spacers.
6. 6

   Remove rear control arm mounting bolt
   Locate the rear mounting bolt that secures the radius arm to the rear subframe mounting point. Remove this bolt completely using a socket and breaker bar. The radius arm should now be free to remove.
7. 7

   Remove radius arm from vehicle
   Lower the support jack slightly and maneuver the radius arm out from between the subframe and steering knuckle. You may need to rotate or angle the arm to clear surrounding components. Inspect the mounting points on the subframe for damage or corrosion.
8. 8

   Clean mounting surfaces
   Use a wire brush to clean the mounting bolt holes in the subframe and the ball joint taper seat in the steering knuckle. Remove any rust, dirt, or debris to ensure proper seating of the new radius arm.
9. 9

   Install new radius arm
   Position the new radius arm into place, aligning the ball joint stud with the hole in the steering knuckle. Maneuver the arm so the mounting bushings align with the subframe mounting points. You may need to use a pry bar to align the holes.
10. 10

    Install control arm mounting bolts finger-tight
    Insert both the front and rear control arm mounting bolts through the bushings and subframe. Thread them in by hand until finger-tight only. Do NOT torque these bolts yet - they must be torqued with the vehicle weight on the suspension.
11. 11

    Install and torque ball joint nut
    Thread the ball joint castle nut onto the ball joint stud. Tighten to the specified torque using a torque wrench. Align the castle nut slots with the hole in the stud and install a NEW cotter pin. Bend the cotter pin ends to secure.
    Torque spec

    Ball Joint Nut88 Nm (65 lb-ft)
12. 12

    Reinstall wheel and lower vehicle
    Install the wheel and thread lug nuts on by hand. Lower the vehicle until the tire just contacts the ground but the full weight is not yet on the suspension. Torque the lug nuts in a star pattern to specification. Then lower the vehicle completely to the ground.
    Torque spec

    Wheel Lug Nuts136 Nm (100 lb-ft)
13. 13

    Torque control arm bolts with weight on suspension
    With the vehicle sitting on the ground at normal ride height, torque both the front and rear control arm mounting bolts to specification. This ensures the bushings are not preloaded in a twisted position, which would cause premature wear.
    ⚠Failure to torque control arm bolts with vehicle weight on wheels will cause premature bushing failure.
    Torque spec

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

    Reconnect battery and test
    Reconnect the 12V auxiliary battery negative terminal. Start the vehicle and turn the steering wheel lock-to-lock to verify full range of motion without binding or noise. Check for any warning lights on the instrument cluster.

Reassembly

1. Ensure new cotter pin is properly installed and bent to prevent loosening
2. Verify all fasteners are torqued to specification with a torque wrench
3. Double-check that control arm bolts were torqued with vehicle weight on suspension

Verification

• Test drive vehicle at low speed and verify no clunking or unusual noises from suspension
• Turn steering wheel through full range while stationary - should be smooth with no binding
• Visually inspect ball joint area for proper cotter pin installation
• Check wheel alignment - radius arm replacement typically requires alignment adjustment
• Verify no warning lights are illuminated on instrument cluster

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