Toyota Prado: Power Steering Rack Knock and Rattle Over Bumps

The 150 Series Prado rack-and-pinion hydraulic power steering rack develops a knock or clunk when the wheels are turned over undulations or speed bumps. The failure mode is internal rack wear causing excessive play between the rack and the housing yoke spring. The yoke plug loosens progressively and the spring pre-load on the rack teeth reduces, allowing the rack to knock against the housing. Toyota released a revised yoke adjustment procedure but on higher-mileage vehicles the rack itself has worn beyond adjustment and requires replacement. The fault is also caused by worn inner tie rod ends within the rack assembly.

• Clunking or knocking noise from the front of the vehicle when driving over bumps or dips with the steering in the straight-ahead position
• Vague or wandering steering feel with a dead spot in the centre of the wheel travel
• Knock felt through the steering wheel when one front wheel drops into a pothole
• Noise changes or worsens when the steering is turned slightly off-centre while traversing rough surfaces

With the vehicle on level ground and engine running, push and pull the steering wheel side to side with both hands — any clunk or knock indicates excessive rack play. Drive slowly over a speed bump while holding the wheel straight and listen for a knock from below the engine bay. Have a mechanic check inner tie rod end play at the rack.

Parts involved: Steering rack.

$400 to $2,500 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.

• “Has the steering rack or inner tie rod ends been replaced or adjusted?”
• “Do you notice any knocking from the front when going over speed bumps?”
• “Does the steering feel vague or have a dead spot in the centre?”

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.