A brake system is the most critical safety system on a car and your customer’s brake system can make all the difference when trying to avoid a collision. It’s imperative that the products we offer are dependable and valuable.

The Problem

  • Moisture is naturally absorbed by brake fluid over time.
  • Increased moisture content lowers the boiling point of the brake fluid.
  • A lower boiling point can cause sluggish brake response to brake failure.
  • Some vehicles require low-viscosity fluids and experience poor performance when viscosity is out of specification.
  • Brake System Contaminants:
    • Moisture – water absorbed by brake fluid, degrades the fluid’s ability to remain as low-compressible fluid and results in extended stopping distances, soft or spongy brake pedal, and potential braking failure.
    • Air – pockets in the brake system displace fluid, is highly compressible, contribute to lost heat transfer, and significantly degrade the system’s braking effectiveness.
    • Copper – The Automotive Maintenance and Repair Association (AMRA) recommends that brake fluid be tested for copper contamination.
      • Brake fluid replacement service should be performed, for most vehicles, when testing shows that copper content exceeds 200 ppm.
      • Industry data shows that this increased presence of copper contamination predetermined the rapid growth of iron contamination and corrosion that has been shown to impede future brake system performance.
  • Inhibitor depletion – it is a known fact that the brake fluid is designed to protect against corrosion of the system and materials it contacts and that those corrosion inhibitors deplete over time.

The Solution

The single most effective preventative maintenance service you can perform to maintain the integrity and effectiveness of your vehicle’s brake system is periodic brake fluid replacement.

To solve this, we typically recommend:

  • A complete exchange of brake fluid.
  • New brake fluid fed into the master cylinder reservoir.
  • All moisture and air are eliminated from the brake system.
  • Wynn’s brake fluid exceeds U.S. Department of Transportation (DOT) specifications.

This should be performed any time a brake job is completed. It will help reduce wear and tear on brake system components and help prevent brake failure.

A bit of Background on Brakes

In a hydraulic brake system, pressing the brake pedal moves a piston within the master cylinder, forcing the brake fluid (a hydraulic fluid) through the brake lines to the slave cylinders at each wheel.

Pistons within these slave cylinders, moved by the pressure from the brake fluid, then move the brake lining into contact with the brake drum to slow and stop the vehicle.

This braking force transmitted to the wheels uses friction to slow and stop the wheels from spinning. To achieve maximum performance, the brake system relies on the use of a low-compressible fluid called brake fluid. Brake fluid serves as a force multiplier, transferring the multiply the pressure from the driver’s foot to the wheel cylinders and braking components.

Fluids that boil when compressed do not have the same multiplying abilities as a low-compressible fluid. That is why the boiling point characteristics of brake fluid are extremely important.

Brakes generate a tremendous amount of heat and brake fluid must remain liquid, without boiling, to operate properly. In addition, brake fluid must withstand subzero temperatures without thickening.

There are Federally mandated standards for brake fluid established by the U.S. Department of Transportation (DOT) that all brake fluids must meet or exceed. These mandates are known as “DOT Standards” and include minimum “dry” and “wet” boiling points:

  • Polyalkylene Glycol Ether
    • DOT 3
    • DOT 4 (includes DOT 4LV)
    • DOT 5.1
  • Silicone
    • DOT 5

Glycol-based fluids are hygroscopic:

  • Water absorbing
  • Boiling point drops with increasing water content
  • Vapor in brake lines is compressible.
  • Brake fluid must be replaced periodically to eliminate the contaminated unsafe fluid.

Silicone-based fluids are not hygroscopic:

  • They are, however, compressible at high temperatures.
  • They foam at high pressures n small orifices such as the solenoid valves in ABS systems.
  • They cause rubber seals to swell, causing brake drag and the fluid must be replaced periodically.