The rubber boot protecting a constant velocity joint has split. Once it's open, the grease flings out and road grit gets in, and the joint itself starts wearing rapidly — that's what causes the clicking on full lock people describe.
Wording as it commonly appears on an MOT certificate: “Constant velocity joint gaiter damaged so that it no longer prevents the ingress of dirt”.
What does it mean?
The rubber boot protecting a constant velocity joint has split. Once it's open, the grease flings out and road grit gets in, and the joint itself starts wearing rapidly — that's what causes the clicking on full lock people describe.
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?
- Age and perishing of the rubber
- Grit trapped in the folds cutting through from the outside
- A clip that's failed and let the boot work loose
What a mechanic would check
Look for the tell-tale spray of grease around the inside of the wheel arch — that's usually visible before the split is. Then I'd turn the wheel to full lock and inspect the boot all the way round, and listen for clicking on a slow full-lock turn, which tells you the joint is already worn.
What might need replacing
- A gaiter kit with fresh grease, if the joint is still good
- A complete driveshaft, if the joint is worn or clicking
Can you still drive it?
It's a failure. Caught early it's a cheap boot; left for months it becomes a driveshaft. The clicking noise on full lock is the deciding factor — once that starts, the joint is already on its way out.
Repair cost
A gaiter kit is far cheaper than a driveshaft, which is exactly why it's worth doing quickly. Ask the garage to check the joint for play and noise before deciding which route to take.
Before the retest
Re-check the specific item on your certificate yourself before the retest — catches that latch first time, no fuel smell or drips under the car, doors that open from inside and out. Most of these are inexpensive repairs, so it is worth also looking over any advisories on the certificate while the car is booked in, rather than waiting for them to become failures next year.
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 other mot items 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.