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LeaksUrgency: As soon as possible

Brake fluid leak: causes and the faults that trigger it

A drop in the brake fluid level can indicate a leak, which also lets air into the circuit; the weak points the sources cite are the brake hoses, the pipes, the master cylinder and the calipers. If the red warning light comes on or the pedal sinks, RACE and Autopista ask for the circuit to be checked without delay.[1][2][3]

One documented fault causes it in the 1.6 GDi híbrido (Kappa):

What to do now

As soon as possible

Do not keep driving if the pedal sinks or loses firmness: check the reservoir level and take the car to a garage before driving any further.

What it means

Brake fluid escapes from the hydraulic circuit, normally through a hose, a flexible line or a deteriorated seal, and usually leaves stains or drips near a wheel.

General explanation from MotorFiable. How it shows up in each engine, with sources, is in the list of faults.

45 sourcesHow we work

Most common causes

From most to least likely according to the sources. Under each cause, the part and the related OBD codes.

  1. 1. Cracked brake hose or pipe

    Common cause

    Autopista cites leaks, cracks and progressive loss of pressure as typical faults of brake hoses and pipes. RACE names a split hose as a cause of a low level.[2][3]

    Faults with with the brake system

  2. 2. Leaking master cylinder

    Possible cause

    RACE says a fluid leak with poor braking can be due to a worn or faulty master cylinder; Autopista adds that if the pedal sinks slowly the priority is to check the master cylinder, circuit and leaks.[2][4]

    Faults with with the brake systemFaults with with the brake servo

  3. 3. Leaking or seized brake caliper

    Possible cause

    RACE describes how a cracked dust boot lets dirt in and seizes the caliper, and how old fluid can clog the hose; a caliper that doesn't release heats up and brakes on one side only.[5]

    Faults with with brake calipers and discs

  4. 4. Cracked fluid reservoir

    Uncommon

    RACE mentions a crack in the reservoir among the causes of low fluid level that turns on the red warning light.[3]

    Faults with with the brake system

  5. 5. Low level without a leak due to worn pads

    Common cause

    RACE clarifies that the level also drops when the pads wear, without any leak: if the reservoir is half full and there are no leaks, the pads need checking.[1][3]

    Faults with with brake calipers and discs

Depending on what you notice

Stain or drip near a wheel

Autopista places hoses and pipes as the route the fluid takes to each wheel; coches.com recommends looking for drips under the car and checking the reservoir level.[2][6]

The brake pedal sinks or feels soft

RACE links a soft or sinking pedal to air in the circuit or low fluid, and a leak with poor braking to the master cylinder. Autopista asks for the master cylinder, circuit and leaks to be checked if the pedal sinks slowly.[2][4]

The red brake warning light comes on

RACE links it to a low fluid level from a leak or badly worn pads and recommends stopping as soon as possible and calling a tow truck if it doesn't go out; coches.com suggests checking the level, leaks and brake lights.[3][6]

The reservoir level is low

RACE warns that, if there is a leak, you should not top up before bleeding the circuit, and that bleeding is done by a specialist with a vacuum machine.[1]

The car brakes and pulls to one side

RACE includes a fluid leak among the causes of the car pulling to one side when braking, along with tyre pressure, alignment or badly bedded-in pads.[4]

What to check first

  1. Look at the fluid reservoir under the bonnet: the level should be between minimum and maximum. The fluid is corrosive, so handle it with care.[1]
  2. Look for stains or drips under the car and near each wheel, and check the hoses and pipes for cracks.[2][6]
  3. Check the thickness of the pads: if the level is at half without a leak, it may be simple wear.[1][3]
  4. Press the pedal with the car stationary and the engine running: if it sinks or feels soft, there is air or a leak.[2][4]
  5. Don't top up with a leak that hasn't been bled: ask the garage to locate the leak, repair it and bleed the circuit.[1]

Can I keep driving?

Urgency: As soon as possible

RACE recommends checking the system as soon as possible when the warning light signals a low level, and stopping and calling a tow truck if the red warning light stays on; with a leak, poor braking or a pedal that sinks, the sensible thing is not to keep driving. A leak can leave the circuit without pressure and brake failure can cause a serious accident.[2][3][4]

How much it costs to fix

Indicative prices published by the sources cited; they depend on the car and the garage.

RepairPrice
Complete brake fluid change (RACE, plus labour; the leak repair is extra)[1]€40

Documented faults that cause it

Specific engine and gearbox faults, from most to least important (severity × frequency). Below each title, how the symptom shows up in that fault.

Faults elsewhere in the car that cause it

Suspension, brake, electronics and other faults on specific cars, from most to least important.

  1. Source for the symptom in the Suzuki Jimny III[8][9][10]

  2. Source for the symptom in the Alfa Romeo Giulietta[11]

  3. Source for the symptom in the Audi A4 B6[12]

  4. Source for the symptom in the Audi e-tron[13][14]

  5. Source for the symptom in the Citroën C4 X[15]

  6. Source for the symptom in the DS DS 3 Crossback[16]

  7. Source for the symptom in the Fiat Ducato III[17]

  8. Source for the symptom in the Ford Ranger[18]

  9. Source for the symptom in the Mercedes-Benz Citan W415[19]

  10. Source for the symptom in the Mercedes-Benz Clase S W223[20]

  11. Source for the symptom in the Mercedes-Benz Clase V W447[14]

  12. Source for the symptom in the Mercedes-Benz Clase V W447[21]

  13. Source for the symptom in the Mercedes-Benz Sprinter 907[22]

  14. Source for the symptom in the Mercedes-Benz Vito W447[21]

  15. Source for the symptom in the Porsche Taycan[23]

  16. Source for the symptom in the Toyota Celica VII[24]

  17. Source for the symptom in the Chevrolet Cruze[25]

  18. Source for the symptom in the Chevrolet Orlando[25]

  19. Source for the symptom in the Ford S-Max II[14]

  20. Source for the symptom in the Ford Tourneo Courier[26]

  21. Source for the symptom in the Ford Transit Courier[26]

  22. Source for the symptom in the Lexus IS II[14]

  23. Source for the symptom in the Mercedes-Benz Clase M W163[27]

  24. Source for the symptom in the MG ZT[28]

  25. Source for the symptom in the Renault Espace V[29][30]

  26. Source for the symptom in the Renault Talisman[31][32][33][34]

  27. Source for the symptom in the Rover 200 R3[35]

  28. Source for the symptom in the Rover 25[36]

  29. Source for the symptom in the Subaru Impreza III[14]

  30. Source for the symptom in the Subaru Legacy V[14]

  31. Source for the symptom in the Subaru Outback IV[14]

  32. Source for the symptom in the Subaru XV I[14]

  33. Source for the symptom in the Volkswagen Caddy V[37]

  34. Source for the symptom in the Volvo S40 I[38]

  35. Source for the symptom in the Alfa Romeo 166[39]

  36. Source for the symptom in the Citroën C4 Cactus[40]

  37. Source for the symptom in the Mercedes-Benz CLA C118[41]

  38. Source for the symptom in the Toyota Yaris III[42]

  39. Source for the symptom in the Jaguar XJ X351[14]

  40. Source for the symptom in the Mercedes-Benz CLA C118[43]

  41. Source for the symptom in the Nissan Qashqai II[44]

  42. Source for the symptom in the Mazda 3 II[45]

Which cars it appears in

This fault affects the 1.6 GDi híbrido (Kappa). We have documented 5 models from 2 makes with some of the affected versions: open yours to see all its faults.

Brake fluid leak: causes in your car

45 cars have several documented faults that cause this symptom. Choose yours to see only those that affect it, by engine and by year.

Brake fluid leak by brand

Frequently asked questions

How do I know if I'm losing brake fluid?

RACE says that a drop in the level can mean a leak and that the red warning light comes on when it falls below the minimum; you should also look for stains under the car and check the condition of the hoses.[1][2][6]

Can I top up the brake fluid myself?

RACE warns that, if there is a leak, you should not add fluid before bleeding the circuit, and that bleeding is not a job for amateurs. Nor should you fill to the maximum if the pads are new, because it can overflow.[1]

Can you drive with a brake fluid leak?

It is not sensible: a circuit with a leak can lose pressure and make the pedal sink. RACE recommends stopping and calling a tow truck if the red warning light stays on.[3][4]

How often does brake fluid need changing?

RACE and Autopista cite about two years, or whatever the manufacturer specifies; the fluid absorbs moisture and its boiling point drops.[1][2]

Is a drop in level always a leak?

No. According to RACE, it also drops through pad wear.[1][3]

Other symptoms: leaks

Has this happened to you? Tell us which fault it was, at how many kilometres and how much you paid: it helps other owners know what to expect. Report your fault.

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Líquido de frenos del coche: ¿cuánto cuesta cambiarlo y cuándo se debe hacer?RACE · Motoring press · published 29 October 2020 · consulted 29 October 2026 · in Spanish
  2. Freno de servicio del coche: la pieza clave de tu seguridad que debes entender y cómo funcionaAutopista · Motoring press · published 23 July 2026 · consulted 29 October 2026 · in Spanish
  3. ¿Qué significa cada testigo rojo del coche?RACE · Motoring press · published 23 June 2026 · consulted 29 October 2026 · in Spanish
  4. ¿Qué debes hacer si fallan los frenos de tu coche?RACE · Motoring press · published 14 December 2023 · consulted 29 October 2026 · in Spanish
  5. La pinza de freno se queda frenada, ¿por qué?RACE · Motoring press · published 20 April 2023 · consulted 29 October 2026 · in Spanish
  6. Testigo del freno de mano puesto siempre encendido: ¿Por qué?coches.com · Motoring press · published 29 September 2021 · consulted 29 October 2026 · in Spanish
  7. Kia Niro 1.6 GDI Hybrid Spirit DCT6 (09/16 - 08/18): datos técnicos y retiradasADAC · Technical documentation · consulted 30 October 2026 · in German
  8. Suzuki Jimny Probleme: Mängel, Schwachstellencarwiki.de · Other source · consulted 29 October 2026 · in German
  9. Suzuki Jimny: Gebrauchtwagen kaufenAUTO ZEITUNG · Motoring press · consulted 29 October 2026 · in German
  10. Suzuki Jimny im TÜV-Report 2022Schwäbische Zeitung (Auto Bild TÜV Report 2022) · Reliability study · published 14 February 2022 · consulted 29 October 2026 · in German
  11. Recall: Alfa Romeo Giulietta (2017) accident, brakescar-recalls.eu · Other source · published 9 March 2018 · consulted 29 October 2026
  12. Fiabilité Audi A4 (2001-2007)fiches-auto.fr · Reliability study · consulted 27 September 2026 · in French
  13. Audi Q8 e-tron (2023-2024): recall por fugas en los latiguillos de frenocar-recalls.eu (datos Safety Gate) · Other source · published 14 July 2024 · consulted 9 October 2026
  14. DVSA – base de llamadas a revisiónDVSA (Reino Unido) · Other source · consulted 9 October 2026
  15. C4 III, C4X Voiture particulière (fiche de rappel SR/02103/25)Rappel Conso (Gobierno de Francia) · Safety Gate UE · Official body · published 13 June 2025 · consulted 5 October 2026 · in French
  16. Fiabilité DS3 Crossback (2019) : pannes et rappelsfiches-auto.fr · Technical documentation · consulted 27 September 2026 · in French
  17. Fiat Ducato (2014-2019): llamada a revisión por las tuberías de frenocar-recalls.eu · Other source · published 22 March 2021 · consulted 9 October 2026
  18. Ford Ranger Raptor (2019): brake hoses recall (Safety Gate A12/1952/19)car-recalls.eu · Other source · published 14 December 2019 · consulted 5 October 2026
  19. Mercedes Citan W415 – Bekannte Probleme & Schwachstellengebrauchtwagenberater.de · Motoring press · published 30 May 2023 · consulted 5 October 2026 · in German
  20. Mercedes ruft S-Klasse zurück: BremsproblemGebrauchtwagenberater · Motoring press · published 26 October 2026 · consulted 29 October 2026 · in German
  21. Mercedes-Benz V-Class/Vito (2018-2019): brake recallcar-recalls.eu (reproduce la alerta A12/1375/19 de Safety Gate) · Other source · published 19 September 2019 · consulted 8 October 2026
  22. Mercedes-Benz Sprinter (2017 – 2020): front brake hosescar-recalls.eu · Other source · published 15 May 2020 · consulted 5 October 2026
  23. Todos los Porsche Taycan vendidos tendrán que pasar por el taller: pueden estar afectados por un problema en los frenosMotorpasión · Motoring press · published 28 June 2024 · consulted 9 October 2026 · in Spanish
  24. Toyota Celica – Brake fluid may leak (R/2004/168)car-recalls.co.uk · Other source · published 25 April 2005 · consulted 5 October 2026
  25. Chevrolet UK Cruze: Brake Fluid May Leak (R/2015/034)Car-Recalls.co.uk (reproduce DVSA) · Other source · consulted 31 October 2026
  26. Rückruf für Ford Tourneo/Transit Courier: Brandgefahr am Kleintransporterauto motor und sport · General press · published 9 July 2026 · consulted 5 October 2026 · in German
  27. Gebrauchtwagen-Test: Mercedes M-Klasse (ab 1997)AUTO BILD · Motoring press · consulted 29 October 2026 · in German
  28. MG ZT Car Check: MOT History, Reliability & FaultsCarVerify · Reliability study · consulted 30 October 2026
  29. Renault Espace (2015–2016): recall for the front flexible brake hosecar-recalls.eu · Other source · published 19 May 2016 · consulted 29 October 2026
  30. Renault Espace (2016): recall for the ABS/ESC hydraulic unitcar-recalls.eu · Other source · published 4 August 2016 · consulted 29 October 2026
  31. Renault Talisman (2015–2016): recall for the front flexible brake hosecar-recalls.eu · Other source · published 19 May 2016 · consulted 29 October 2026
  32. Renault Talisman (2015–2016): recall for the brake caliper/disc combinationcar-recalls.eu · Other source · published 15 June 2017 · consulted 29 October 2026
  33. Renault Talisman (2016): recall for the ABS/ESC hydraulic unitcar-recalls.eu · Other source · published 4 August 2016 · consulted 29 October 2026
  34. Renault Talisman – Typische Probleme & Krankheitengebrauchtwagenberater.de · Motoring press · published 15 January 2023 · consulted 29 October 2026 · in German
  35. Rover 200 Car Check: MOT History, Reliability & FaultsCarVerify · Reliability study · consulted 30 October 2026
  36. Rover 25 Car Check: MOT History, Reliability & FaultsCarVerify · Reliability study · consulted 30 October 2026
  37. Volkswagen Caddy (2024): recall by brake linecar-recalls.eu · Other source · published 24 January 2025 · consulted 4 October 2026
  38. Volvo Car V40 – Brake caliper concern (recall DVSA R/1999/100; S40, V40)car-recalls.co.uk (DVSA, Reino Unido) · Other source · published 18 November 1999 · consulted 5 October 2026
  39. Alfa Romeo 166: betrouwbaarheid (datos de la ITV neerlandesa APK)Autozine · Reliability study · consulted 30 October 2026 · in Dutch
  40. Fiabilité Citroën C4 Cactus (2014-2020) : pannes et rappelsfiches-auto.fr · Technical documentation · consulted 27 September 2026 · in French
  41. Mercedes-Benz CLA (2024): latiguillos de freno traseros demasiado largos (alerta 26/2025)Car-Recalls.eu (EU Safety Gate) · Other source · consulted 29 October 2026
  42. Toyota Yaris (2013): fuga de líquido de frenos traserosCar-recalls.eu · Other source · published August 2013 · consulted 27 September 2026
  43. Mercedes CLA 2 (2019) : pannes et problèmes (12 avis)fiches-auto.fr · Other source · consulted 5 October 2026 · in French
  44. Nissan Qashqai J11: Probleme, Schwachstellen und RückrufeGebrauchtwagenberater.de · Motoring press · consulted 29 October 2026 · in German
  45. Mazda3 im TÜV: Das sind die Schwachstellen, Mängel und StärkenAuto Bild · Reliability study · consulted 29 October 2026 · in German