Brake's liquid

The main difference lies in their boiling point. The higher the DOT rating, the higher the temperature the fluid can withstand before boiling:

• DOT 3: Suitable for older vehicles with less demanding braking systems.
• DOT 4: The most common fluid for modern cars, ideal for systems equipped with ABS and ESP.
• DOT 5.1: A high-performance fluid with a very high boiling point, suitable for heavy-duty use or high-performance vehicles.

Brake fluid is hygroscopic, meaning it absorbs moisture from the air over time. The presence of water in the system dramatically lowers the fluid's boiling point, which can lead to a loss of braking power (the pedal feels "spongy") during heavy braking. Additionally, moisture causes internal corrosion in the metal components of the braking system.

The general advice is to avoid mixing. While DOT 3, 4, and 5.1 are glycol-based and theoretically compatible, the resulting mixture will only perform as well as the lowest-rated fluid. Warning: Never mix glycol-based fluids (DOT 3, 4, 5.1) with silicone-based fluids (DOT 5), as this will cause immediate damage and failure of the braking system.

The brake fluids we offer at Geosantro (Würth series) exceed international safety standards. They provide:

• Excellent Corrosion Protection: Specialized additives that protect lines and pistons.
• Stability in Extreme Temperatures: Ensuring immediate brake response in both freezing and high-heat conditions.
• Rubber Component Compatibility: They do not degrade the seals and rubber parts of the system.

The required fluid type is usually printed on the brake fluid reservoir cap in the engine bay or in your owner's manual. If you have any doubts about whether you need a standard DOT 4 or a specialized low-viscosity fluid for modern ABS systems, contact Geosantro. Our team will guide you based on your manufacturer's specifications for maximum road safety.