Upper Control Arm - Rear

This procedure covers the removal and replacement of the rear upper control arm on a 2015 Kia Forte, including disconnecting the ball joint from the knuckle and removing the control arm mounting bolts.

Warnings

Tools required

Parts

• Rear upper control arm × 1 — Use OEM specification
• Ball joint castle nut (if not reusable) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Loosen rear wheel lug nuts while vehicle is on ground
3. Raise rear of vehicle and support securely on jack stands at manufacturer-approved lift points
4. Remove rear wheel on side being serviced
5. Spray control arm bolts and ball joint nut with penetrating lubricant if corrosion is present

Procedure

1. 1

   Support rear knuckle assembly
   Position a floor jack under the rear knuckle/spindle assembly to support the suspension components. Raise jack slightly to take up weight but do not compress the suspension. This prevents the knuckle from dropping when the control arm is disconnected.
2. 2

   Remove ball joint castle nut
   Locate the upper control arm ball joint where it connects to the rear knuckle. Remove the cotter pin if equipped. Using a 17mm socket, remove the castle nut securing the ball joint to the knuckle. Do not allow the ball joint stud to spin while removing the nut.
   Torque spec

   Ball Joint Nut84 Nm (62 lb-ft)
3. 3

   Separate ball joint from knuckle
   Install a ball joint separator tool or pickle fork between the upper control arm ball joint and the knuckle. Tighten or strike the tool to break the taper fit between the ball joint stud and knuckle. Once separated, remove the tool and carefully lower the jack slightly to allow the knuckle to drop away from the control arm.
   ⚠The knuckle may drop suddenly when the ball joint releases. Ensure the jack is positioned to control the descent.
4. 4

   Remove front control arm mounting bolt
   Locate the front mounting bolt that secures the upper control arm to the suspension subframe or chassis. This is typically the smaller of the two mounting points. Using a 17mm socket and wrench, remove the bolt completely. Note the orientation of any washers or spacers for reinstallation.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
5. 5

   Remove rear control arm mounting bolt
   Locate the rear mounting bolt that secures the upper control arm to the suspension subframe or chassis. Using a 19mm socket and wrench, remove the bolt completely. Support the control arm as you remove the final bolt to prevent it from falling.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
6. 6

   Remove upper control arm
   Carefully maneuver the upper control arm out of the suspension assembly. You may need to pivot or angle the arm to clear the knuckle and subframe. Inspect the mounting points on the chassis for damage or excessive wear.
7. 7

   Prepare new control arm
   Compare the new upper control arm to the old unit to verify correct part. Check that the ball joint moves freely and boots are intact. Clean the mounting surfaces on the chassis with a wire brush to ensure proper seating of the new control arm bushings.
8. 8

   Install new control arm to chassis
   Position the new upper control arm into the mounting brackets on the suspension subframe. Insert the front and rear mounting bolts through the control arm bushings and chassis brackets. Thread bolts by hand initially to ensure proper alignment. Do not fully tighten at this time - only snug the bolts finger tight plus 1-2 turns.
   ℹ️Control arm bolts must NOT be torqued until vehicle weight is on the wheels to prevent bushing bind.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
9. 9

   Connect ball joint to knuckle
   Raise the floor jack under the knuckle to align the ball joint stud with the hole in the knuckle. You may need to use a pry bar to maneuver the knuckle into position. Insert the ball joint stud through the knuckle and install the castle nut. Tighten the nut to specification using a torque wrench.
   Torque spec

   Ball Joint Nut84 Nm (62 lb-ft)
10. 10

    Install cotter pin
    If the ball joint uses a castle nut with cotter pin, align the castle nut slots with the hole in the ball joint stud. Install a new cotter pin and bend the ends to secure. If slots do not align, tighten the nut slightly (never loosen) until alignment is achieved, not exceeding 10% over specified torque.
11. 11

    Reinstall wheel and lower vehicle
    Install the rear wheel and thread lug nuts by hand. Lower the vehicle until the tire just contacts the ground but vehicle weight is still partially on jack stands. Torque wheel lug nuts to specification in a star pattern. Remove jack stands and lower vehicle completely to the ground.
    Torque spec

    Wheel Lug Nuts129 Nm (95 lb-ft)
12. 12

    Torque control arm mounting bolts
    With the vehicle weight fully on the wheels and suspension at normal ride height, torque the front and rear control arm mounting bolts to specification. This ensures the control arm bushings are in their neutral position and prevents premature wear. Use a torque wrench and apply torque in a single smooth motion.
    ⚠This is a critical step. Torquing with suspension unloaded will cause bushing failure.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)

Reassembly

1. Ensure all fasteners are tightened to proper specifications
2. Verify cotter pin is properly installed and secured on ball joint
3. Double-check wheel lug nuts after first 50 miles of driving

Verification

• Bounce the rear of the vehicle to settle the suspension and verify no unusual noises
• Visually inspect that the control arm is properly seated in mounting brackets
• Test drive vehicle and verify no clunking, pulling, or unusual tire wear patterns
• Schedule a professional wheel alignment as rear suspension geometry has been altered

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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