Blog 7: BMW Steering Rack Clunk - The Hidden Thrust Piece Failure
If you own a BMW and have noticed a clunking or knocking noise from the front end, especially at low speeds or when turning the steering wheel, you’re not alone. One of the most common—and often misdiagnosed—causes is steering rack thrust piece failure.
This issue affects many BMW models and can drive owners and technicians crazy because it often doesn’t show up as play in the tie rods or suspension. Let’s break down what’s happening, why it occurs, and how it’s fixed.
What Is the Steering Rack Thrust Piece?
Inside BMW’s electric and hydraulic steering racks is a small but critical component called the thrust piece (sometimes referred to as a pressure piece or preload adjuster).
Its job is to:
Apply constant pressure to the rack gear.
Eliminate internal play.
Keep steering tight and precise.
Over time, this thrust piece—usually made of plastic or composite—wears down or cracks, allowing the rack gear to move slightly inside the housing. The buffer pads are often completely missing from the thrust piece when removed from the steering rack.
That tiny amount of movement is what creates the dreaded steering clunk.
Common Symptoms of Thrust Piece Failure
A failing thrust piece usually causes very specific symptoms:
Clunk or knock felt through the steering wheel (typically front the drivers side front of the car)
Noise most noticeable at low speeds.
Clunk when changing steering direction (left to right).
Noise when driving over small bumps or rough pavement.
Loose feel to steering input.
Why This Issue Is So Common on BMWs
BMW prioritizes steering feel and precision, which means:
Tight tolerances inside the rack.
High internal loads.
Materials that wear faster under real-world conditions.
Poor original design utilising plastic components (BMW now sell a revised part).
Here you can see the difference between the original (yellow) and the revised (grey) steering rack thrust piece.
For thyssen steering rack ONLY, shown in the 2nd photo. This is not applicable to ZF steering racks.
Repair Options: Rack Replacement vs. Thrust Piece Repair
1. Steering Rack Replacement
Most expensive option.
Often unnecessary if rack gears are otherwise healthy.
Can cost thousands with labour.
2. Thrust Piece Repair Kit
Replaces the worn internal thrust piece
Restores proper preload
Eliminates clunk in most cases
Fraction of the cost of rack replacement
Many enthusiasts and independent BMW specialists now opt for thrust piece repair kits, which address the root cause rather than replacing the entire rack. The steering rack thrust piece upgrade kit is available here or we offer installation at our workshop.
Our experienced technicians follow BMW’s exact procedures, ensuring your vehicle is repaired perfectly and runs like new.
Whether you drive a 320d or M3, we’ve got the expertise and tools to get the job done right.
Catching problems early can save you thousands in repair bills and keep your BMW performing as it should.
📍 Book your vehicle in today with BM Performance — your trusted BMW MINI specialist.
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