MOT advisory explained
“Brake hose slightly deteriorated”
A flexible brake hose with cracks in its outer rubber. It is an advisory of old age: it does not exist on cars under seven years old, it is heavily concentrated in a handful of German models, and a third of owners simply carry it over to the next test.
Each wheel’s brake is fed through a short length of reinforced rubber hose that flexes as the suspension moves and the wheels steer. The tester bent one and saw surface cracking in its outer cover. The reinforcement underneath is not exposed and it does not bulge under pressure, so it passes.
5.1% fail on a brake hose at the next test, and 33.8% are advised again unchanged. The outer cover cracks long before the hose is weak, which is why so many linger. It is still the only thing between the pedal and that brake.
This is about the rubber hoses. Rust on the metal brake lines is a separate advisory, “brake pipe corroded”, which fails about twice as often. Older cars frequently have both.
A “brake hose slightly deteriorated” advisory means a flexible rubber brake hose has surface cracking or perishing in its outer cover, but the reinforcement is not exposed and it does not bulge, so the car passes. The fix is new hoses, normally fitted as a pair with a brake fluid bleed. According to DVSA MOT data analysed by PriceMyRepair, 5.1% of 735,057 such advisories failed on a brake hose at the next test, and 33.8% were advised again.
What the tester looks for in a hose
How it is built. A brake hose is an inner rubber tube, one or two layers of woven reinforcement, and an outer rubber cover. The reinforcement holds the pressure. The cover only protects it from weather and abrasion. Deteriorated, in MOT terms, nearly always means the cover.
How it is checked. The tester turns the steering from lock to lock, bends each hose by hand to open up any cracks, and has an assistant press the brake pedal while watching for a bulge. Fine cracks in the cover are an advisory. Cracks deep enough to show the reinforcement, chafing through the cover, or any swelling under pressure is a fail.
The two ways a hose fails. It can burst, which loses that brake circuit at once. Modern cars have two circuits, so you keep some braking, with a long pedal. Or the inner tube can collapse and act as a one-way valve, so the brake applies but will not release. A brake that binds on an old car with perished hoses is often this.
Will it fail next year?
735,057 of these advisories can be followed to the same vehicle’s next MOT, fewer than usual because many of the cars that get it are near the end of their lives.
| What happened at the next test | Share |
|---|---|
| Failed on the same component | 5.1% |
| Same advisory recorded again | 33.8% |
According to DVSA MOT data analysed by PriceMyRepair: 735,057 advisories followed to the same vehicle’s next test. Rows can overlap.
It sits mid-table among the brake advisories. Corroded brake pipes fail 10.1% of the time and a binding brake 9.3%, both well above this. Slight corrosion on a hose’s metal end fitting is lower, at 3.4%.
The repeat rate is the more telling number. One in three is written down again a year later. Hoses are cheap, but the job means opening the hydraulic system, so it tends to be put off until something else needs doing to the brakes.
| Advisory wording | Fails on same part | Advised again | Followed |
|---|---|---|---|
| Brake pipe corroded, covered in grease or other material | 10.1% | 44.4% | 7,889,073 |
| Service brake binding | 9.3% | 14.4% | 2,418,487 |
| Brake pad(s) wearing thin | 7.2% | 16.9% | 13,888,197 |
| Brake hose slightly deteriorated | 5.1% | 33.8% | 735,057 |
| Brake disc worn, pitted or scored, | 3.7% | 31.2% | 15,014,091 |
| Brake hose has slight corrosion to ferrule | 3.4% | 32.0% | 1,265,734 |
| Brake disc worn, | 2.6% | 12.9% | 3,690,262 |
Below seven years old there are too few cases to report at all. At 7–9 years it appears on 0.4 of every 1,000 tests. Past twenty years it is on more than one test in fifty. The failure rate rises the same way, from 1.5% to 6.0%.
| Age of car | Per 1,000 tests | Fails on same part | Followed |
|---|---|---|---|
| 7–9 years | 0.4 | 1.5% | 15,904 |
| 10–12 years | 2.4 | 2.8% | 87,950 |
| 13–15 years | 8.9 | 5.0% | 235,762 |
| 16–19 years | 17.6 | 6.0% | 265,060 |
| 20 years and over | 21.5 | 5.8% | 116,151 |
A brake hose does not wear. It ages. Ozone, heat from the brakes and years of flexing harden the rubber until it cracks, and a car that has covered forty thousand miles gets there at about the same time as one that has covered a hundred and forty.
That is why the advisory arrives in a wave at ten to fifteen years old, and why it arrives on both sides at once. “both” and “both sides” are the two most common notes testers add.
If the pedal feels spongy, sinks slowly under steady pressure, or one wheel stays hot after a drive, do not leave this until the next test. Those are signs of a hose that is failing inside.
Exact wording on your certificate
Hoses have two separate advisories, one for the rubber and one for the metal fitting at each end. This page covers the rubber. The failure wording is the same sentence with a stronger adverb.
| Line on the certificate | Result | Code |
|---|---|---|
| Brake hose slightly deteriorated | Advisory — pass | 1.1.12 (b) (ii) |
| Brake hose excessively deteriorated | Major — fail | 1.1.12 (b) (ii) |
The front hoses account for about six in ten. They work harder than the rears, because they have to follow the steering as well as the suspension, and they sit next to the hottest brakes on the car. Left and right are level.
| Position written by the tester | Share of all instances |
|---|---|
| Offside front | 27% |
| Nearside front | 27% |
| Nearside rear | 15% |
| Offside rear | 15% |
| Front | 7% |
| Rear | 5% |
From 2,531,470 recorded instances. Testers can add their own note after the standard wording. The most common on this advisory: “both” (85,089), “both sides” (60,230), “both front” (22,793), “all” (16,537), “perished” (16,172), “nearside and offside” (14,584), “both rear” (13,588), “cracking” (10,667).
What is involved in replacing them
Hoses themselves are inexpensive parts. The bill is mostly labour: each hose is unscrewed from a metal pipe that is often corroded at the union, and the system has to be bled afterwards. We do not publish a range because seized unions can turn a short job into a longer one, and we would be guessing. Ask for a price for the axle pair including a fluid bleed. Related brake prices are on the brake caliper replacement cost page.
Can I still drive with this advisory?
Have the hoses replaced at the next service or within a few months. Treat it as urgent if the brake pedal changes feel, a brake starts to drag, or you see fluid on the inside of a wheel.
Enter your reg to see every brake advisory in your car’s history. Hoses and pipes flagged together point to one visit, one fluid bleed.
Which cars get this advisory most?
On the average vehicle this appears on 4.4 of every 1,000 tests. On one maker’s cars it is in a different league.
| Model | Per 1,000 tests | Vs all cars | Tests |
|---|---|---|---|
| BMW 120 | 74 | 16.8× | 466,460 |
| BMW 3 Series | 53 | 12.1× | 4,399,110 |
| BMW 118 | 35 | 8.0× | 1,290,940 |
| BMW 116 | 27 | 6.2× | 1,102,596 |
| Audi A4 | 24 | 5.5× | 2,768,934 |
| Volvo V70 | 24 | 5.4× | 542,743 |
| BMW Z4 | 22 | 4.9× | 345,780 |
| Volkswagen Touareg | 19 | 4.3× | 356,943 |
| Volkswagen Transporter | 19 | 4.3× | 3,128,645 |
| Volkswagen Beetle | 19 | 4.2× | 586,588 |
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.
Five of the ten are BMWs. The BMW 120 gets this advisory 16.8 times as often as the average vehicle, the BMW 3 Series 12.1 times on the back of more than four million tests, and the BMW 118, BMW 116 and BMW Z4 follow. DVSA lists the 1 Series under its engine badges, so 116, 118 and 120 are one car.
The rest of the list is also German or Swedish and also ageing: the Audi A4, Volvo V70 and three Volkswagens. If you own one of these at ten years old or more, expect this line, and expect it on both sides.
What to do next
- Look for braid. Bend the hose and look into the cracks. Rubber all the way down is an advisory. Anything woven or pale showing through is a fail waiting to happen.
- Do the axle, not the side. The other hose is the same age. The system is bled once either way.
- Have the fluid changed at the same time. It has to be bled anyway, and brake fluid on a car of this age is usually overdue.
- Ask about the unions first. If the metal pipe ends are badly rusted, they may need replacing with the hose. Better to hear that in the quote than halfway through the job.
Brake hose deteriorated advisory FAQ
What does brake hose slightly deteriorated mean?
A flexible rubber brake hose has surface cracking or perishing in its outer cover. The reinforcement inside is not exposed and the hose does not bulge under pressure, so it is an advisory and the car passes.
Will a deteriorated brake hose fail the next MOT?
Sometimes. According to DVSA MOT data analysed by PriceMyRepair, 5.1% of 735,057 such advisories failed on a brake hose at the next test, and 33.8% were given the same advisory again.
Is it safe to drive with a slightly deteriorated brake hose?
Yes, at this stage. Cracks in the outer cover do not reduce its strength. Replace the hoses within a few months, and straight away if the pedal goes spongy or a brake starts to drag.
How much does it cost to replace brake hoses?
The hoses are cheap and the cost is mainly labour, including bleeding the brakes. It varies with how corroded the pipe unions are, so we do not publish a range. Any prices on this site are estimates and final quotes come from garages.
Should brake hoses be replaced in pairs?
Yes. Both hoses on an axle are the same age and perish together, and the brakes have to be bled whichever you change. Testers most often record this advisory against both sides.
Why do BMWs get this advisory so often?
The data shows it clearly but does not explain it. The BMW 120 gets it 16.8 times as often as the average vehicle and five of the top ten models are BMWs. It is a known age-related item on those cars and a routine job for any garage.
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 2,531,470 times; 735,057 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.