Warning: Never Use Brake Fluid as Lubricant!

Brake fluid is an essential component of any hydraulic brake system, playing a crucial role in transmitting force from the master cylinder to the brake calipers. While its primary function is to transfer pressure, a common misconception is that brake fluid also serves as a lubricant. This blog post aims to clarify this matter and provide a comprehensive understanding of brake fluid’s properties and its role in the braking system.

What is Brake Fluid?

Brake fluid is a specialized hydraulic fluid specifically designed for use in brake systems. It typically consists of a base fluid, such as polyglycol ether or mineral oil, along with additives that enhance its performance and protect against corrosion.

Is Brake Fluid a Lubricant?

No, brake fluid is not a lubricant. It lacks the necessary properties to effectively lubricate moving parts in a brake system. Lubricants, on the other hand, are designed to reduce friction between surfaces in contact, preventing wear and tear.

Brake fluid is formulated to transmit pressure efficiently and resist the extreme temperatures and pressures encountered in brake systems. It is not intended to provide lubrication for brake components such as calipers, pads, or rotors.

Why Brake Fluid is Not a Lubricant

There are several reasons why brake fluid is not suitable as a lubricant:

• Low Viscosity: Brake fluid has a low viscosity compared to lubricants, meaning it flows easily and does not provide the necessary film strength to separate moving parts.
• Hygroscopic Nature: Brake fluid absorbs moisture from the atmosphere, which can reduce its effectiveness and corrode metal components.
• Lack of Additives: Brake fluid does not contain additives that are found in lubricants, such as anti-wear agents and extreme pressure additives, which are essential for preventing friction and protecting against wear.

Consequences of Using Brake Fluid as a Lubricant

Using brake fluid as a lubricant can have detrimental effects on the braking system:

• Reduced Braking Performance: Brake fluid cannot effectively reduce friction, leading to increased stopping distances and potential brake fade.
• Premature Component Wear: The lack of lubrication can accelerate wear on brake components, resulting in costly repairs or replacements.
• Corrosion: Brake fluid’s hygroscopic nature can promote corrosion of metal parts, weakening the brake system and compromising safety.

Proper Lubrication of Brake Components

Brake components require proper lubrication to function optimally and extend their lifespan. Specialized brake lubricants are formulated to withstand the harsh conditions within the brake system and provide the necessary lubrication for:

• Caliper slides
• Pad contact points
• Rotor hubs

These lubricants are typically silicone- or ceramic-based and are designed to reduce friction, prevent wear, and protect against corrosion.

When to Change Brake Fluid

Brake fluid should be changed regularly according to the vehicle manufacturer‘s recommendations. This is because it absorbs moisture over time, which can reduce its boiling point and increase the risk of brake fade. Changing brake fluid is a crucial maintenance procedure that ensures the proper functioning and safety of the braking system.

Summary

Brake fluid is not a lubricant and should not be used as such. Its primary function is to transmit pressure and protect against corrosion in the brake system. Using brake fluid as a lubricant can have negative consequences for braking performance, component wear, and system integrity. Proper lubrication of brake components should be done using specialized brake lubricants to ensure optimal performance and longevity.

Frequently Asked Questions

Q: What is the difference between brake fluid and lubricant?

A: Brake fluid is a hydraulic fluid designed for transmitting pressure in brake systems, while lubricant is a substance that reduces friction between moving parts.

Q: Can I use brake fluid to lubricate my brake pads?

A: No, brake fluid is not suitable for lubricating brake pads. Use specialized brake lubricants designed for this purpose.

Q: How often should I change my brake fluid?

A: Refer to your vehicle manufacturer‘s recommendations for the specific interval. Typically, it ranges from 1 to 3 years.

Q: What happens if I don’t change my brake fluid?

A: Over time, brake fluid absorbs moisture, which reduces its effectiveness and can lead to brake fade and corrosion.

Q: Can I use DOT 3 brake fluid in a DOT 4 system?

A: Yes, DOT 3 fluid is compatible with DOT 4 systems, but DOT 4 fluid should not be used in DOT 3 systems.