Procedure to remove and replace the front upper control arm on a 2023 Chevrolet Bolt EUV, including disconnection of the ball joint and control arm mounting bolts.

Warnings

Tools required

Parts

• Upper control arm assembly × 1 — Use OEM specification
• Cotter pin × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks behind rear wheels
3. Loosen front wheel lug nuts while vehicle is on ground
4. Raise front of vehicle with floor jack at manufacturer-approved jacking point
5. Support vehicle securely on jack stands under frame rails
6. Remove front wheel on side being serviced

Procedure

1. 1

   Access upper control arm area
   Inspect the upper control arm and mounting points. Clean area around ball joint nut and control arm bolts with wire brush. Apply penetrating lubricant to fasteners if corrosion is present and allow to soak for several minutes.
2. 2

   Remove ball joint cotter pin
   Locate the ball joint nut connecting the upper control arm to the steering knuckle. Remove and discard the cotter pin from the ball joint castle nut using pliers or cotter pin removal tool. The cotter pin must be replaced with a new one during reassembly.
3. 3

   Loosen ball joint nut
   Using a 19mm socket, loosen but do not fully remove the ball joint castle nut. Leave the nut threaded on by several turns to prevent the knuckle from dropping suddenly when the taper breaks free.
4. 4

   Separate ball joint from knuckle
   Position ball joint separator tool between the upper control arm and steering knuckle. Apply pressure to break the tapered connection. Once the taper breaks free, remove the ball joint nut completely. Support the knuckle to prevent strain on brake hose and wheel speed sensor wiring.
   ⚠Do not strike the ball joint stud with a hammer as this can damage the threads or ball joint. Use proper separator tool only.
5. 5

   Remove control arm rear mounting bolt
   Locate the rear control arm mounting bolt that secures the control arm to the frame rail. Using an 18mm wrench to hold the nut and a 21mm socket on the bolt head, remove the rear mounting bolt completely. Note the orientation of any washers or spacers for reinstallation.
6. 6

   Remove control arm front mounting bolt
   Locate the front control arm mounting bolt. Using an 18mm wrench to hold the nut and a 21mm socket on the bolt head, remove the front mounting bolt completely. Support the control arm as you remove the final bolt.
7. 7

   Remove upper control arm
   With both mounting bolts removed and ball joint disconnected, carefully remove the upper control arm from the vehicle. Inspect the mounting points on the frame for damage, corrosion, or worn bushings in the frame brackets.
8. 8

   Install new upper control arm
   Position the new upper control arm into the frame mounting brackets. Insert the front and rear mounting bolts through the control arm bushings and frame brackets. Thread the nuts onto the bolts finger-tight only. Do not torque at this time as these bolts must be torqued with vehicle weight on wheels.
9. 9

   Connect ball joint to knuckle
   Align the ball joint stud with the hole in the steering knuckle. You may need to use a pry bar or jack to raise the knuckle slightly to align the taper. Install the ball joint castle nut and tighten to specification. Ensure the castle nut slots align with the cotter pin hole. If necessary, tighten the nut slightly more (never loosen) to align the slots.
   Torque spec

   Ball Joint Nut88 Nm (65 lb-ft)
10. 10

    Install new cotter pin
    Insert a new cotter pin through the ball joint stud hole and castle nut. Bend the ends of the cotter pin to secure it in place, ensuring it cannot back out during vehicle operation.
11. 11

    Install wheel and lower vehicle
    Install the wheel onto the hub and thread the lug nuts on by hand. Lower the vehicle from jack stands until the tire is just touching the ground but the suspension is not fully loaded. Torque the wheel lug nuts to specification in a star pattern. Do not fully lower vehicle yet.
    Torque spec

    Wheel Lug Nuts136 Nm (100 lb-ft)
12. 12

    Torque control arm bolts with weight on wheels
    Lower the vehicle completely so full vehicle weight is on the wheels. This ensures the suspension is at normal ride height. Using a torque wrench, torque both the front and rear control arm mounting bolts to specification. This must be done with the vehicle on the ground to prevent premature bushing wear.
    ⚠Torquing control arm bolts with suspension unloaded will cause premature bushing failure. Vehicle weight must be on wheels.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)

Reassembly

1. Final torque values are critical for this repair - verify all fasteners are torqued to specification
2. Ensure new cotter pin is properly installed and secured on ball joint
3. Control arm mounting bolts must be torqued at normal ride height with vehicle weight on wheels

Verification

• Verify ball joint nut is torqued to specification and new cotter pin is properly installed and bent
• Confirm both control arm mounting bolts are torqued to specification with vehicle weight on wheels
• Check that wheel lug nuts are torqued to specification in star pattern
• Test drive vehicle at low speed and verify no unusual noises or handling issues
• Recommend alignment check after control arm replacement to ensure proper suspension geometry

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