Idler Arm

This procedure explains how to replace the lower control arm ball joint on a 2016-2021 Honda Civic 1.5L Turbo, as this vehicle uses a ball joint assembly rather than a traditional idler arm.

Warnings

Tools required

Parts

• Lower control arm with ball joint × 1 — Use OEM specification
• Ball joint castle nut × 1 — Use OEM specification or included with control arm
• Cotter pin × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Loosen front wheel lug nuts while vehicle is on ground
3. Raise front of vehicle with floor jack at designated lift points
4. Support vehicle securely on jack stands under chassis rails
5. Remove front wheel on side requiring repair
6. Spray penetrating oil on ball joint castle nut and control arm mounting bolts, allow to soak

Procedure

1. 1

   Remove ball joint castle nut cotter pin
   Straighten and remove the cotter pin from the ball joint castle nut at the steering knuckle. Use pliers to pull the pin completely out. Discard the old cotter pin as it should not be reused.
2. 2

   Loosen ball joint castle nut
   Using a 17mm socket, loosen the ball joint castle nut but do not remove it completely. Leave it threaded on a few turns to protect the threads when using the ball joint separator.
   ℹ️Leaving the nut partially threaded prevents damage to the ball joint stud threads during separation.
3. 3

   Separate ball joint from knuckle
   Position ball joint separator tool between the lower control arm and steering knuckle. Tighten the tool to apply pressure on the ball joint taper. Strike the knuckle area near the ball joint with a hammer while maintaining pressure until the taper releases. Remove the castle nut completely once separated.
   ⚠Ball joint may release suddenly. Ensure the nut is still threaded to prevent the control arm from dropping violently.
4. 4

   Support lower control arm
   Place a floor jack or jack stand under the lower control arm to support it once the mounting bolts are removed. This prevents the arm from falling and makes installation of the new arm easier.
5. 5

   Remove control arm rear mounting bolt
   Locate the rear control arm mounting bolt at the subframe. Using a 19mm socket and breaker bar, remove the rear mounting bolt completely. This bolt typically connects the control arm to the rear bushing bracket.
6. 6

   Remove control arm front mounting bolt
   Using a 19mm socket and breaker bar, remove the front control arm mounting bolt from the subframe. Note the orientation of any washers or spacers for reinstallation.
7. 7

   Remove lower control arm
   Lower the support jack slightly and maneuver the control arm assembly out from the suspension. The ball joint stud should slide down and out of the steering knuckle. Remove the control arm completely from the vehicle.
8. 8

   Clean mounting surfaces
   Use a wire brush to clean the subframe mounting points and steering knuckle ball joint taper. Remove any corrosion, dirt, or debris. Inspect the steering knuckle taper for damage or excessive wear.
   ℹ️A damaged knuckle taper will not hold the ball joint properly and must be replaced.
9. 9

   Install new lower control arm
   Position the new control arm assembly into place. Insert the ball joint stud into the steering knuckle taper. Align the control arm bushings with the subframe mounting points. Thread the front and rear mounting bolts finger-tight but do not torque yet.
10. 10

    Install and torque ball joint castle nut
    Install the new castle nut onto the ball joint stud. Torque the castle nut to specification. Align the castle nut slots with the ball joint stud hole by tightening only (never loosen to align). Install a new cotter pin through the castle nut and ball joint stud, then bend the pin ends to secure.
    ⚠Only tighten the castle nut to align cotter pin hole, never loosen it. Over-tightening is acceptable within reason.
    Torque spec

    Tie Rod Castle Nut55 Nm (41 lb-ft)
11. 11

    Load suspension before final torque
    Lower the vehicle until the suspension is at normal ride height but the wheel is still off the ground (use jack under control arm or lower vehicle onto blocks). This loads the control arm bushings in their normal operating position before final torque.
    ℹ️Torquing suspension bushings with suspension hanging can cause premature bushing failure and binding.
12. 12

    Torque control arm mounting bolts
    With the suspension loaded to ride height, torque the front and rear control arm mounting bolts to specification using a torque wrench and 19mm socket.
    Torque spec

    Mounting Bolts26 Nm (19 lb-ft)
13. 13

    Reinstall wheel
    Raise vehicle completely off jack stands. Install the wheel and thread lug nuts by hand. Lower vehicle to ground and torque lug nuts to specification in a star pattern.
    Torque spec

    Wheel Lug Nuts129 Nm (95 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to specification before driving vehicle
2. Verify cotter pin is properly installed and bent on ball joint castle nut
3. Double-check that all tools and parts have been removed from under vehicle

Verification

• Test drive vehicle at low speed and verify no unusual noises from suspension
• Check for proper steering response and no pulling to either side
• Schedule a professional wheel alignment within 50 miles of this repair, as control arm replacement affects camber and caster angles
• After 50-100 miles, re-check torque on control arm mounting bolts and wheel lug nuts

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