MOT advisory explained
“Brakes imbalanced requirements only just met”
The brakes on one axle are not pulling equally. The rollers measured the difference, and it came in just under the limit. It is a number, the tester usually writes it down, and it points at one wheel whose brake is not doing its share.
The roller brake tester measures the force at each wheel separately. On one axle, the weaker side produced noticeably less than the stronger side. The legal limit is a difference of thirty per cent. Yours was close to it and still inside.
4.8% fail on brake imbalance at the next test and 8.0% fail on service brake performance of some kind. Only 6.4% get the same advisory again, one of the lowest repeat rates of any advisory we track. An imbalance this close to the line rarely sits still: it is put right, or it crosses over.
One side, fitted, independent garage. That is the dearer outcome. A caliper that is only sticking can often be stripped, cleaned and lubricated for a labour charge, and contaminated pads are cheaper still.
The weaker brake is normally the faulty one, not the stronger. A car that pulls to the left under braking has a lazy brake on the right. Make sure the garage investigates the correct side. Common causes and prices are on the brake caliper replacement cost page.
A “brakes imbalanced requirements only just met” advisory means the roller brake tester found one brake on an axle noticeably weaker than the other, but within the thirty per cent limit, so the car passes. The usual cause is a sticking caliper or contaminated pads on the weaker side. A replacement front caliper costs £150–£340 fitted. According to DVSA MOT data analysed by PriceMyRepair, 8.0% of 690,135 such advisories were followed by a service brake failure at the next test.
What the rollers compared
The measurement. Each wheel sits on its own pair of rollers and the machine records the peak braking force at each. The tester compares left with right on the same axle. If the weaker side is less than seventy per cent of the stronger, the car fails. On a steered axle, less than half is graded dangerous.
What testers write down. The difference itself. The three most common notes on this advisory are “28%”, “29%” and “27%”, followed by a run of figures just below them. These are brakes one or two points from failing, recorded by testers who thought the owner should know how close it was.
Why one side goes weak. A caliper sliding on corroded pins cannot clamp squarely. A sticky piston applies late and lightly. Pads contaminated with oil, grease or brake fluid lose their grip. A brake hose collapsing inside restricts the flow to that wheel. On rear drums, a seized wheel cylinder or an automatic adjuster that has stopped working does the same.
Will it fail next year?
Four closely related wordings are grouped on this page, all ending with the tester’s note that the system needs adjustment or repair. Together they cover 1,541,285 advisories, of which 690,135 can be followed to the next MOT.
| What happened at the next test | Share |
|---|---|
| Failed on the same component | 4.8% |
| Failed on anything under defect 1.2.1 | 8.0% |
| Same advisory recorded again | 6.4% |
According to DVSA MOT data analysed by PriceMyRepair: 690,135 advisories followed to the same vehicle’s next test. Rows can overlap.
Use the second row. A car advised for imbalance may fail next time on imbalance, on efficiency, on binding or on fluctuation, depending on how the fault develops, and 8.0% fail on one of them. That puts it between a fluctuating brake at 7.0% and a binding one at 10.6%.
The third row is the striking one. At 6.4% this has one of the lowest repeat rates we have measured, and the lowest of the common brake advisories. A roller reading is sensitive to the day: tyre pressures, damp rollers and cold brakes all move it a few points. A car on twenty-eight one year may read twenty-two the next with nothing changed, or thirty-three.
| Advisory wording | Fails on same part | Fails under same code | Advised again | Followed |
|---|---|---|---|---|
| Parking brake efficiency only just met. It would appear that the braking system requires adjustment or repair | 12.3% | 12.3% | 12.1% | 314,204 |
| Service brake binding | 9.3% | 10.6% | 14.4% | 2,418,487 |
| Brake pad(s) wearing thin | 7.2% | 7.2% | 16.9% | 13,888,197 |
| Service brake fluctuating, | 5.9% | 7.0% | 13.3% | 1,274,510 |
| Brake hose slightly deteriorated | 5.1% | 5.1% | 33.8% | 735,057 |
| Brakes imbalanced requirements only just met. It would appear that the braking system requires adjustment or repair | 4.8% | 8.0% | 6.4% | 690,135 |
| Brake disc worn, | 2.6% | 2.7% | 12.9% | 3,690,262 |
Age matters more here than for almost any other brake advisory. The rate rises about sevenfold between 3–4 years and 20 years and over, and the share that fail on imbalance next time rises nearly fivefold, from 1.6% to 7.7%. On an old car this is not a reading to shrug at.
| Age of car | Per 1,000 tests | Fails on same part | Followed |
|---|---|---|---|
| 3–4 years | 1.3 | 1.6% | 35,856 |
| 5–6 years | 2.0 | 2.4% | 57,445 |
| 7–9 years | 3.2 | 3.7% | 124,275 |
| 10–12 years | 5.0 | 4.7% | 153,581 |
| 13–15 years | 6.7 | 5.5% | 144,281 |
| 16–19 years | 8.2 | 6.4% | 108,414 |
| 20 years and over | 9.4 | 7.7% | 49,200 |
On a straight, empty road, brake firmly with a light grip on the wheel. If the car drifts to one side, the brake on the opposite side is the weak one. Front imbalance is felt through the steering. Rear imbalance is much harder to feel and shows up in an emergency stop, when the back of the car steps sideways.
An imbalance near the limit is usually too small to notice in ordinary driving, which is why the first most owners hear of it is on the certificate.
A car that pulls sharply under braking, or has started to recently, should be checked now and not at the next service. That is no longer a marginal reading.
Exact wording on your certificate
All four advisories share a second sentence, that the braking system appears to need adjustment or repair. The failure wording drops it.
| Line on the certificate | Result | Code |
|---|---|---|
| Brakes imbalanced requirements only just met. It would appear that the braking system requires adjustment or repair | Advisory — pass | 1.2.1 (b) (i) |
| Service brake requirements only just met. It would appear that the braking system requires adjustment or repair | Advisory — pass | 1.2.1 (c) |
| Service brake imbalance requirements only just met. It would appear that the braking system requires adjustment or repair | Advisory — pass | 1.2.1 (b) (i) |
| Service brake efficiency only just met. It would appear that the braking system requires adjustment or repair | Advisory — pass | 1.2.2 (a) (i) |
| Brakes imbalanced across an axle | Major — fail | 1.2.1 (b) (i) |
Testers record the axle and not the wheel, since imbalance is a comparison between two wheels. Rear and front are almost level. Rear drum brakes go out of adjustment on one side, and front calipers stick on one side, in about equal numbers.
| Position written by the tester | Share of all instances |
|---|---|
| Rear | 46% |
| Front | 42% |
| No position recorded | 3% |
| Nearside rear | 2% |
| Offside rear | 2% |
| Nearside front | 1% |
From 1,541,285 recorded instances. Testers can add their own note after the standard wording. The most common on this advisory: “28%” (10,151), “29%” (9,408), “27%” (7,413), “25%” (5,135), “26%” (5,134), “24%” (3,859), “30%” (3,354), “23%” (2,620).
What it costs, depending on the cause
| Job | Price fitted | Notes |
|---|---|---|
| Front caliper, one side | £150–£340 | If the weak side’s caliper is seized |
| Rear caliper, one side | £170–£380 | Rear axle, disc brakes |
| Front discs and pads, both sides | £200–£330 | If the pads are contaminated or glazed |
Fitted prices at an independent garage. The cheapest outcomes are not in the table: freeing and lubricating a sticking caliper, or adjusting rear drum brakes, is a labour-only job. If pads are contaminated, find where the oil or fluid came from before fitting new ones. Prices by model are on the brake caliper replacement cost page.
Can I still drive with this advisory?
Leave a little more room in the wet and be aware the car may not stop dead straight in an emergency. Have the brakes inspected within a few weeks. Stop driving and get it looked at if the car pulls hard to one side when you brake.
Enter your reg to see the full MOT record. An imbalance advisory following a binding or hose advisory on the same axle usually shares its cause.
Which cars get this advisory most?
The all-vehicle rate is 3.1 per 1,000 tests. The models that lead are mostly vehicles that carry weight.
| Model | Per 1,000 tests | Vs all cars | Tests |
|---|---|---|---|
| Mitsubishi L200 | 8 | 2.5× | 935,407 |
| Toyota Hilux | 7 | 2.2× | 734,628 |
| Mazda 6 | 6 | 2.0× | 728,629 |
| Toyota Corolla | 6 | 2.0× | 1,166,652 |
| Vauxhall Movano | 6 | 2.0× | 544,309 |
| Peugeot 206 | 6 | 2.0× | 1,061,894 |
| Renault Master | 6 | 1.9× | 760,734 |
| Suzuki Alto | 6 | 1.9× | 556,815 |
| Renault Kangoo | 6 | 1.8× | 700,467 |
| Citroen Relay | 6 | 1.8× | 662,399 |
Model families are grouped by the first word of the DVSA model name, so “Transit” covers every Transit variant. Only models with at least 60,000 tests are ranked.
Two pickups head the list, the Mitsubishi L200 and Toyota Hilux, and three large vans follow, the Vauxhall Movano, Renault Master and Citroen Relay. Many have rear drum brakes and a valve that alters rear braking with load. Tested empty, with a system set up for a full load, small differences between sides show up large.
The cars on the list, such as the Peugeot 206 and Suzuki Alto, are older small cars with rear drums. Drum brakes depend on self-adjusters that seize with age, and they rarely seize on both sides at once.
What to do next
- Get the figure and the axle. Twenty-nine is one bad morning from a fail. Twenty-two is a note for the file.
- Have the weak side stripped and inspected. Sliders, piston, pads and hose on a disc brake. Cylinder, shoes and adjuster on a drum.
- Look for contamination. A leaking driveshaft seal, wheel cylinder or shock absorber can coat a brake. New pads will not last if the leak stays.
- Ask for a roller retest after the repair. It takes two minutes and gives you a before and after number.
Brake imbalance advisory FAQ
What does brakes imbalanced requirements only just met mean?
On the roller brake tester, one brake on an axle was noticeably weaker than the other, but the difference was inside the legal limit. The car passes, and the wording adds that the system appears to need adjustment or repair.
How much brake imbalance fails an MOT?
A difference of more than thirty per cent between the two wheels on an axle is a failure. On a steered axle, more than fifty per cent is graded dangerous.
Will it fail next year?
According to DVSA MOT data analysed by PriceMyRepair, 8.0% of 690,135 such advisories were followed by a service brake failure at the next test, and 4.8% failed specifically on imbalance. Only 6.4% were given the same advisory again.
What causes brake imbalance?
Usually a sticking caliper or seized slider pins on the weaker side, pads contaminated with oil or fluid, a brake hose collapsing internally, or on drum brakes a seized wheel cylinder or adjuster.
How much does it cost to fix?
Freeing a sticking caliper is a labour-only job. If a caliper needs replacing, it costs £150–£340 for a front and £170–£380 for a rear, fitted at an independent garage. These are estimates and final quotes come from garages.
Which brake is the faulty one?
Normally the weaker one. If the car pulls to one side under braking, the brake on the opposite side is not doing its share. Ask the tester which side read lower.
How these figures were calculated. According to DVSA MOT data analysed by PriceMyRepair, from the DVSA anonymised MOT test results (Open Government Licence v3.0): 350,943,111 tests. This advisory was recorded 1,541,285 times; 690,135 of those were followed to the same vehicle’s next test between 180 and 730 days later. “Fails on the same part” means a failure at that next test under the same defect code and naming the same component, on either side of the vehicle. Testers do not always name a component the same way twice, so the figure is a floor. Method and how to cite.