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Brake fluid Mercedes A-Class W177 (2018–2023) — DOT 4 Plus specification

Brake fluid for Mercedes A-Class W177 (2018–2023) — required specification, boiling points, system volume, and approved brands.

Caractéristiques techniques

ParameterValue
Marque / ModèleMercedes A-Class W177
Années de production2018–2023
Spécification du liquideDOT 4 Plus
Point d’ébullition sec260°C
Point d’ébullition humide165°C
Volume du système500 ml
Intervalle de remplacement60 000 km / ans

Marques approuvées

Mercedes-Benz Brake Fluid / ATE SL DOT 4 Plus / Castrol DOT 4 LLT

Why Brake Fluid Must Be Changed Regularly

Brake fluid is hygroscopic — it absorbs moisture from the air over time. As moisture content increases, the boiling point drops significantly. When the fluid boils under heavy braking, vapour bubbles form and the pedal goes to the floor (vapour lock). Mercedes requires DOT 4 Plus with a dry boiling point of at least 260°C.

How to Check Brake Fluid Condition

  1. Test strips — dip a strip in the reservoir; colour indicates moisture content
  2. Electronic tester — measures boiling point directly (most accurate)
  3. Visual inspection — dark/brown fluid indicates it must be replaced (fresh fluid is amber/clear)

Questions fréquentes

What brake fluid does Mercedes A-Class W177 use?

DOT 4 Plus specification. Point d’ébullition sec: 260°C. Volume du système: 500 ml. Marques approuvées: Mercedes-Benz Brake Fluid / ATE SL DOT 4 Plus / Castrol DOT 4 LLT.

How often should I change brake fluid in Mercedes A-Class W177?

Every 60 000 km or every ans — whichever comes first. This is a safety-critical service.

Can I mix different DOT grades?

You can mix DOT 3 and DOT 4 in an emergency, but never mix DOT 5 (silicone-based) with DOT 3/4 (glycol-based). Always use the correct specification: DOT 4 Plus.