There's more movement in that suspension arm than there should be. The wording names both the pin (the joint) and the bush (the rubber mount) because from underneath, with a pry bar, the tester can see the movement but can't always tell which of the two is producing it.
Wording as it commonly appears on an MOT certificate: “Suspension arm pin or bush excessively worn”.
What does it mean?
There's more movement in that suspension arm than there should be. The wording names both the pin (the joint) and the bush (the rubber mount) because from underneath, with a pry bar, the tester can see the movement but can't always tell which of the two is producing it.
How serious is it?
Usually recorded as: Major. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- Perished rubber bushes — they harden and crack with age and UV as much as with mileage
- A worn ball joint at the outer end of the arm
- Pothole or kerb impact having deformed the arm or split a bush
- A torn dust boot letting grit into a joint, which then wears rapidly
What a mechanic would check
Car in the air, wheel supported, and lever the arm at both ends while someone watches. If the movement is at the inboard mount it's the bush; if the ball joint is nodding, it's the joint. I'd also grab the wheel at three and nine o'clock to separate arm play from a worn wheel bearing or track rod end, because they can feel similar from the driver's seat.
What might need replacing
- Bushes pressed out and replaced, if they're available separately for your car
- The complete lower arm, which on many modern cars is the only way it's supplied
- A ball joint, where it's a separate serviceable part
- A four-wheel alignment afterwards — anything that moves the arm changes the geometry
Can you still drive it?
It's a failure, so the car isn't roadworthy on that basis. What it means in practice varies: a slightly soft bush is a knock over speed bumps, whereas a badly worn ball joint is the failure mode nobody wants at speed. Since the certificate can't tell you which one you've got, treat it as needing prompt attention rather than something to leave until payday.
Repair cost
Varies considerably. A pressed-in bush on a car where bushes are sold separately is inexpensive; a complete arm on a car where the joint and bush are integral costs considerably more, and then there's alignment on top. Get the failed component confirmed before ordering parts.
Before the retest
Suspension parts such as springs, shock absorbers and drop links are normally replaced in pairs across an axle so the car sits level and handles evenly. Any work that disturbs the steering or suspension geometry is worth following with a wheel alignment check, otherwise you can pass the retest and still wear out a new pair of tyres within months. Listen for the original knock again on a bumpy road before the retest — if it is still there, something was missed.
Retest rules
If the vehicle stays at the test centre for repair and is retested within 10 working days, a partial retest is often free; some items qualify for a free retest if you bring the car back by the end of the next working day. The exact conditions are set out on GOV.UK, so confirm with the test centre before you leave. A major or dangerous failure means the car cannot legally be driven away unless the previous MOT is still valid and nothing dangerous was recorded — check your certificate first.
Related help
More suspension failures · MOT failure decoder · Ask a mechanic about your certificate
This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.