Brake hose deteriorated, damaged or chafing

What causes it

• Age. Rubber perishes from the outside in whether the car is driven or not, so low-mileage cars are not exempt
• A hose fitted slightly too short or twisted, so it rubs a tyre, spring or suspension arm at full lock
• A missing or broken retaining bracket letting the hose swing into something
• Internal delamination after years of heat cycling next to the brake disc, which restricts flow without showing outside

Advisory or failure?

A hose that is chafing but has not been damaged through its outer cover is a minor defect — recorded, but not a failure. Once the hose is excessively damaged, cut, twisted, kinked, or is seen bulging under brake pressure, it becomes a major defect. A hose that is leaking, or whose failure looks imminent, is graded dangerous. Testers apply the brakes with the vehicle raised specifically to look for bulging, so a hose that is fine at rest can still fail the test.

Can you fix it yourself?

Possible with care

Swapping a flexible hose is a contained job: undo the union at the pipe end, unclip the bracket, unbolt the hose from the calliper, fit the new one, then bleed that corner. The care is in the detail. Support the vehicle properly on axle stands, never a jack alone. Use a brake union spanner rather than an open-ended one, because the soft unions round off easily. Fit the new hose without a twist and check it clears everything at full lock in both directions before you put the wheel back on. Bleed until the pedal is firm with the engine off, and never reuse old fluid. If you cannot achieve a solid pedal afterwards, stop and get it looked at rather than testing it on the road.

What it costs

Hoses are cheap parts, typically £15 to £35 each, and the cost is the labour plus the bleed. One hose replaced and bled is usually £70 to £110. Doing a pair across an axle is barely more than one, because the bleed is already priced in, so it is often worth doing both. The top of the band applies where the union has seized into a corroded pipe and the pipe end has to be remade, or where the hose sits behind a shield that has to come off first.

What happens if you ignore it

A perished hose fails suddenly and completely, and unlike a pipe it usually goes at the wheel where the fluid loss is quickest. You lose one circuit, the pedal travel doubles and the car pulls under braking. A collapsed hose is more insidious: it leaves one brake dragging, which cooks the pad, warps the disc and ruins the calliper, so a £90 part turns into a £400 corner. Because hoses are an obvious visual item, a defective one also makes it very hard to argue the car was roadworthy if it is ever inspected after an incident.

Common questions

Is a perished brake hose an MOT failure?

It depends on the extent. A hose that is chafing but has not been damaged through its outer cover is a minor defect, so it is noted without failing the car. A hose that is excessively damaged, cut, twisted, kinked or seen bulging under brake pressure is a major defect, and a leaking hose is graded dangerous.

Why does one of my brakes drag or bite late?

A flexible hose can delaminate internally and behave like a one-way valve, letting pressure reach the calliper but not release afterwards. That leaves the brake dragging once you lift off, or applying later than the others. The hose can look perfect outside, which is why a collapsed one is often found only after pads and discs have been changed needlessly.

Can I change a brake hose myself?

It is possible with care. The hose comes off at the pipe union, the bracket and the calliper, then that corner has to be bled. Support the car on axle stands rather than a jack, use a brake union spanner so the soft unions do not round off, and fit the new hose without a twist, checking it clears everything at full lock both ways.

How much does it cost to replace a brake hose?

The hose itself is cheap at £15 to £35, so the cost is labour plus the bleed. One hose replaced and bled is usually £70 to £110. Doing both sides of an axle costs barely more, because the bleed is already priced in. Expect the top of the band where the union has seized into a corroded pipe.

Is it safe to drive with a bulging brake hose?

No. A perished hose tends to fail suddenly and completely, and usually at the wheel, where fluid is lost fastest. You lose that circuit, pedal travel doubles and the car pulls under braking. A hose is also an obvious visual item, so a defective one makes it very hard to argue the car was roadworthy if it is inspected after an incident.

Cars this happens to most

Of every model with at least 2,000 tests in the DVSA data, these record brake hose deteriorated, damaged or chafing on the largest share of their MOTs. Across all of them the typical rate is 0.5% of tests.

1. Seat Exeo5.0%

   214 times in 4,292 tests

2. Audi A22.6%

   150 times in 5,762 tests

3. Saab 9002.5%

   53 times in 2,115 tests

4. Nissan Primera2.1%

   53 times in 2,490 tests

5. Vauxhall Vectra1.9%

   409 times in 22,040 tests

6. Volkswagen Lupo1.7%

   85 times in 5,137 tests

7. Volvo 900 Series1.4%

   42 times in 2,898 tests

8. Vauxhall Tigra1.4%

   75 times in 5,339 tests

A high rate here is a property of the fleet as much as the car: these models skew old, and almost everything fails more with age. It is a reason to check the item on a used example, not proof the model is badly built. Models with fewer than 2,000 tests are left out because a rate drawn from a few hundred cars moves too much to rank.

Pass rates for every make and model →

The warning light behind this

This defect is what a tester writes down. What you see from the driver’s seat is a symbol, and it is worth checking which one, because manufacturers reuse the same shape for more than one system.

• Brake fluid warning lightWhat it means and whether you can keep driving

Other common defects

• Direction indicator not working
• Stop lamp not working
• Lamp of the wrong colour, position or intensity
• Brake pipe corroded
• See all defects →