Subaru Impreza: Front lower arm inner bush failure causing vibration

The front lower control arm inner pivot bushes on the GH/GE Impreza degrade from around 80,000 km onward, with NZ/AU road conditions accelerating wear. The inner bush is a hydraulic or rubber-bonded unit pressed into the front subframe. When it fails or collapses, the lower arm pivot point moves under braking and cornering loads, producing steering vibration through the wheel under braking, wandering straight-line tracking, and a clunking or knocking sound over sharp bumps. The failure also causes inner-edge tyre wear if camber shifts as the deflected bush alters suspension geometry under load.

• Steering wheel vibration or shimmy felt under moderate to firm braking
• Clunk or knock from front suspension over sharp bumps or during direction changes
• Wandering or imprecise straight-line tracking on smooth roads
• Premature inner-edge tyre wear on one or both front tyres
• Steering pull to one side under braking

Excessive movement at the inner pivot point indicates bush failure. Visually inspect the inner bush rubber for cracking, collapse, or separation from its sleeve. Check for oil leakage if hydraulic bush type is fitted. Verify wheel alignment history. If a workshop inspection is possible: With the vehicle on a hoist, grasp the front lower control arm and attempt to move it fore-and-aft.

Parts involved: Ball joint.

$450 to $1,100 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Have the front lower control arm bushes been inspected or replaced?”
• “Has any steering vibration under braking or straight-line wandering been noticed?”
• “What is the history of wheel alignments and have any abnormal tyre wear patterns been noted?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.