MOT advisory explained
“Anti-roll bar linkage has slight play”
The cheapest suspension advisory there is, and the one most often mistaken for something far more expensive. A rattle over bumps is a drop link long before it is anything else.
A ball joint in one of the short rods connecting the anti-roll bar to the suspension strut has worn. There is movement where there should be none, but not yet enough to fail the test.
Drop links are cheap, quick to fit and require no alignment afterwards. This is the least painful advisory on the certificate.
Per link, fitted. Most garages quote both sides of an axle together at £60–£150, because the second one is nearly free once the car is on the ramp.
A knocking noise is not evidence that “the suspension has gone”. Before agreeing to arms at £140–£280 or shocks at £160–£520, have the links ruled out — on most cars they are the answer.
An “anti-roll bar linkage has slight play” advisory means a ball joint in one of the short rods connecting the anti-roll bar to the suspension has worn, but not enough to fail. Replacing one costs £40–£90 fitted. Of 27 million tracked suspension advisories, 18.7% later returned as a failure.
How this reads on your certificate
The wording varies: “nearside front anti-roll bar linkage has slight play”, “offside rear anti-roll bar link ball joint worn”, sometimes just “drop link has play”. Nearside is the passenger side, offside the driver’s side.
“Slight play” is the phrase that keeps this an advisory. The tester found movement in the joint with a lever, judged it measurable but within limits, and wrote it down. Excessive play in the same joint fails the test — the difference is how much the joint moves, not whether it moves at all.
What a drop link actually does
An anti-roll bar runs across the car and resists body lean in corners by tying the two sides of an axle together. It can only do that if it is connected to the suspension at each end, and the drop links are those connections: short rods, usually with a small ball joint at each end, allowing the strut to move up and down while still pulling on the bar.
Those little joints are among the most worked components on the car. Every ridge, drain cover and pothole articulates them, and unlike a bush they have no rubber to absorb the impact — the ball simply wears in its socket until there is a gap. That gap is what makes the noise: a rattling knock over small sharp bumps, loudest at low speed on rough surfaces, often absent on a smooth motorway.
Because they wear from use rather than age, drop links are the first suspension item to need attention on most cars, and they need it repeatedly across a car’s life. That is normal. It is also why the price is what it is: a simple part, a quick job, no geometry disturbed.
What it costs
| Job | Price fitted | Notes |
|---|---|---|
| Drop link, one side | £40–£90 | Per link, parts and labour |
| Drop links, both sides of an axle | £60–£150 | The usual quote — second side is mostly parts |
| Anti-roll bar bushes, same visit | +£40–£90 | Worth doing together if creaking too |
| Alignment afterwards | Not needed | Links do not set geometry |
Independent garage prices, parts and labour. Main dealers typically charge around 50% more. Full prices by model on the suspension repair cost page.
Enter your reg — we’ll pull every advisory from every test, show which corner keeps being flagged, and price the work for your car.
When it stops being an advisory
Excessive play in the joint fails the test. There is no millimetre figure published for drivers — the tester assesses it with a lever while watching the joint, and the judgement is about how much the ball moves in its socket.
A worn drop link does not, on its own, damage anything else. The anti-roll bar simply stops doing its job properly, so the car leans a little more in corners and rattles over bumps. What it does do is mask other faults: once a link is knocking, a genuinely worn arm bush or top mount is much harder to hear. Clearing the cheap noise is what lets a garage find the expensive one, if there is one.
How often does this advisory become a failure?
We can measure it rather than estimate. The DVSA test record follows every advisory forward to the same vehicle’s later tests, across 27 million suspension advisories.
| What happened next | Suspension | Brake parts | Tyres |
|---|---|---|---|
| Became a failure at a later test | 18.7% | 9.4% | 9.9% |
| Ignored, no action taken | 37.1% | 36.1% | 30.5% |
| Fixed | 44.2% | 54.4% | 59.6% |
| Median advisory to failure | 376 days — the next MOT | ||
Calculated from the DVSA MOT test database (Open Government Licence v3.0), from 27,042,129 tracked suspension advisories. The record groups anti-roll bar links with the rest of the suspension — springs, dampers, arms and bushes — so these figures describe the category this defect belongs to.
Suspension advisories become failures more often than any other category we have measured, and get fixed less often than any other: 18.7% return as a failure, and fewer than half are dealt with inside the year.
The 18.7% applies to the whole suspension category — springs, arms, bushes and links share it. What differs enormously is what the escalation costs you. A spring that goes from advisory to failure is £130–£320. An arm is £140–£280. A drop link is £40–£90.
Same odds, a third of the bill. This is the one suspension advisory where the repair is cheap enough that waiting cannot really save you money — and the fix rate of 44.2% suggests a great many drivers wait anyway, because a rattle is easy to live with.
The real cost of leaving it is not the link. It is that a knocking car hides its other noises, so the arm bush developing quietly underneath goes unheard until the tester finds it.
How the risk changes with the age of the car
Because the record spans two decades, the same figure can be broken down by how old the car was when the advisory was written. Suspension produces the steepest and highest curve of anything in the data.
| Age of car at the advisory | Advisories | Became a failure |
|---|---|---|
| 5 years | 890,803 | 10.7% |
| 10 years | 2,180,862 | 19.0% |
| 15 years | 1,776,192 | 22.3% |
| 20 years | 426,288 | 20.8% |
Same dataset, broken down by vehicle age at the time of the advisory. Beyond twenty years the rate falls again, which reflects which cars are still on the road rather than any improvement in the parts. Contains public sector information licensed under the Open Government Licence v3.0.
At fifteen years, more than one suspension advisory in five comes back as a failure — the highest figure anywhere in the record, for any component group at any age. On a car of that age this section of the certificate is worth more attention than any other.
Drop links are the exception inside their own category, and it is worth saying plainly. Springs corrode and bushes perish, so they get worse as a car ages and that is what drives the curve upwards. Links wear from use rather than from years — they are replaced two or three times over a car’s life and start fresh each time. The rising line above describes the company they keep, not the part itself.
Which is a useful way to read an advisory on an older car. If the certificate names the links on a fifteen-year-old, the links themselves are an ordinary £40–£90 job — but the same corner is now statistically the likeliest place on the car for something dearer to be developing quietly. That is an argument for having the whole corner looked at, not for spending more on the links.
What to do next
- Get the links ruled in or out first. Before agreeing to any suspension work above £100, ask the garage to check the drop links specifically. On most cars a knock over bumps is exactly this, and it is a quick check on the ramp.
- Do both sides of the axle. The second link is mostly parts once the car is up, and links on the same axle have done identical work. £60–£150 for the pair beats £40–£90 twice.
- Add the anti-roll bar bushes if it creaks too. A creak over speed bumps alongside the rattle points at the bar bushes, and they are on the same component at the same corner.
- Do not pay for alignment. Drop links do not set geometry, so a like-for-like replacement needs no alignment afterwards. If it appears on the quote, ask why.
Drop link advisory FAQ
Is a worn drop link dangerous?
Not at the advisory stage, and not seriously even at the failure stage. A worn link means the anti-roll bar is not fully connected, so the car leans a bit more in corners and rattles over bumps. It is a comfort and control issue rather than an immediate safety one — which is why it fails the MOT only once the play is excessive.
How long can I drive with a drop link that has play?
Months, safely. Unlike a spring or a bush, a worn drop link does not damage its neighbours or wear a tyre. The reason to fix it sooner is cost-benefit rather than urgency: at £40–£90 there is no meaningful saving in waiting, and the rattle masks other noises.
Why do drop links wear out so quickly?
Because they are the most worked joints on the car and have no rubber to cushion them. Every bump articulates the small ball joints at each end, and UK road surfaces supply plenty of bumps. Needing them two or three times over a car’s life is normal rather than a fault.
Should drop links be replaced in pairs?
Ideally yes, per axle. They are not safety-critical to match the way springs and dampers are, but both links have done identical work, so the second is usually not far behind. With the car already on the ramp the extra cost is mostly the part — £60–£150 for a pair against £40–£90 for one.
What noise does a worn drop link make?
A rattling or knocking sound over small sharp bumps — drain covers, cat’s eyes, broken tarmac — loudest at low speed and often absent on smooth roads. A creak over speed bumps is more likely the anti-roll bar bushes; a deep clunk over larger bumps points at an arm bush instead.
Do I need wheel alignment after drop links are replaced?
No. Drop links connect the anti-roll bar to the strut and play no part in setting geometry, so a like-for-like replacement leaves the alignment untouched. If alignment appears on a drop-link-only quote, it is worth asking what it is for.
Will a drop link fail my next MOT?
It might — “slight play” this year is frequently excessive play next year, because the joint only wears one way. Suspension advisories become failures more often than any other category we have measured, at 18.7% against 9.4% for brake parts.
Can I replace drop links myself?
They are among the more approachable jobs if you have axle stands and the right sockets, and the parts are inexpensive. The common problem is a seized or spinning ball joint stud, which needs heat or a splitter — which is a large part of why the fitted price is only £40–£90 in the first place.
How often does a drop link advisory become an MOT failure?
18.7% of suspension advisories return as failures — the highest of any category we have measured, against 9.4% for brake parts and 9.9% for tyres. What makes drop links different is not the odds but the stakes: the same escalation costs £40–£90 here, against £130–£320 for a spring or £140–£280 for an arm. On a fifteen-year-old car the category figure peaks at 22.3%.