This procedure covers the removal and replacement of the lower control arm on the front suspension of a 2016-2024 Hyundai Tucson with 2.5L I4 AWD engine.

Warnings

Tools required

Parts

• Lower control arm assembly × 1 — Use OEM specification or quality aftermarket equivalent
• Ball joint castle nut × 1 — Replace if damaged or cotter pin holes stripped
• Cotter pin × 1 — Standard cotter pin for ball joint

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Loosen wheel lug nuts 1/4 turn while vehicle is still on ground
3. Raise front of vehicle with floor jack at designated jacking point
4. Support vehicle on jack stands positioned at frame rails, ensuring vehicle is stable
5. Remove wheel and tire assembly completely
6. Spray penetrating oil on ball joint nut, control arm bolts, and threaded connections; allow to soak 10-15 minutes

Procedure

1. 1

   Disconnect ball joint from knuckle
   Remove the cotter pin from the ball joint castle nut using pliers or cotter pin puller. Using a 17mm socket, remove the ball joint nut completely from the ball joint stud. Position a ball joint separator tool between the lower control arm and the steering knuckle. Tighten or strike the separator tool to break the taper connection between the ball joint and knuckle. The joint may release suddenly.
2. 2

   Support the knuckle assembly
   Once the ball joint is separated, the knuckle and hub assembly will drop down. Support the knuckle and strut assembly with a bungee cord or wire tied to the frame or control it by hand to prevent stress on the brake hose and ABS sensor wire. Do not allow the assembly to hang by the brake hose or CV axle.
3. 3

   Remove front control arm bolt
   Locate the front control arm mounting bolt that connects the control arm to the subframe. Using an 18mm socket and breaker bar, remove the front control arm bolt completely. This bolt passes through the front bushing of the control arm. Support the control arm as you remove the bolt to prevent it from falling.
4. 4

   Remove rear control arm bolt
   Locate the rear control arm mounting bolt that connects the control arm to the subframe. Using an 18mm socket and breaker bar, remove the rear control arm bolt completely. This bolt passes through the rear bushing of the control arm. Once removed, the control arm will be free from the vehicle.
5. 5

   Remove control arm from vehicle
   Maneuver the lower control arm out from between the subframe and knuckle assembly. You may need to use slight force or rotate the arm to clear the ball joint stud through the knuckle. Inspect the removed control arm for bent components, torn bushings, or damaged ball joint boots.
6. 6

   Prepare new control arm
   Unpack the new lower control arm and verify it matches the removed part in configuration, ball joint orientation, and bushing positions. Clean the mounting bolt holes in the subframe using a wire brush to remove rust, dirt, and debris. Inspect the ball joint stud taper hole in the steering knuckle for damage or wear.
7. 7

   Install new control arm to subframe
   Position the new lower control arm into the subframe mounting brackets. Insert both control arm mounting bolts through the bushings and subframe but do NOT tighten them at this stage. Thread the bolts in by hand just enough to hold the control arm in position. The bolts must remain loose until the vehicle weight is on the wheels.
8. 8

   Connect ball joint to knuckle
   Raise the steering knuckle assembly and align the ball joint stud with the hole in the knuckle. Insert the ball joint stud through the knuckle hole, ensuring it seats fully into the taper. Install the new castle nut onto the ball joint stud and tighten it to specification.
   Torque spec

   Ball Joint Nut88 Nm (65 lb-ft)
9. 9

   Install cotter pin
   Align the castle nut slots with the cotter pin hole in the ball joint stud. If slots do not align, tighten the nut slightly (never loosen) until the next slot aligns with the hole. Insert a new cotter pin through the hole and bend the ends to secure it properly.
10. 10

    Reinstall wheel and lower vehicle
    Install the wheel and tire assembly onto the hub. Thread all lug nuts by hand to prevent cross-threading. Snug the lug nuts in a star pattern with a wrench but do not torque yet. Carefully remove the jack stands and lower the vehicle until the wheels contact the ground with full vehicle weight on the suspension, but keep the jack slightly supporting the vehicle.
11. 11

    Torque control arm bolts with weight on wheels
    With the full vehicle weight on the wheels and suspension at normal ride height, torque both control arm mounting bolts (front and rear) to specification using an 18mm socket and torque wrench. This ensures the bushings are not pre-loaded in a twisted position. Remove the jack completely.
    ⚠️Control arm bolts MUST be torqued with vehicle weight on wheels. Failure to do so will cause premature bushing failure and unsafe handling characteristics.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)
12. 12

    Torque wheel lug nuts
    Using a torque wrench and 19mm socket, torque all wheel lug nuts to specification in a star pattern. Perform at least two complete passes around all lugs to ensure even torque distribution.
    Torque spec

    Wheel Lug Nuts136 Nm (100 lb-ft)

Reassembly

1. Double-check that all fasteners are properly torqued, especially control arm bolts and ball joint nut
2. Verify cotter pin is properly installed and secured on ball joint castle nut
3. Confirm no tools or parts were left in the wheel well area

Verification

• Test drive the vehicle at low speed in a safe area and verify no abnormal noises, vibrations, or handling issues
• After 50-100 miles of driving, re-check torque on wheel lug nuts and control arm bolts
• Schedule a professional alignment check, as control arm replacement affects suspension geometry and will cause irregular tire wear if not aligned

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