What Happens If You Put Windshield Washer Fluid in the Brake Fluid?

Windshield washer fluid can ruin your calipers.

When changing fluids in your car, it is important to make sure everything is put in its proper place. To avoid ruining your brakes with windshield washer fluid, note the locations of each reservoir and the blue color of the washer fluid.

Brake Sensitivity

Many people neglect to change their brake fluid for thousands of miles, if they even change it at all. However, even a small amount of moisture in the brake reservoir -- as little as three percent -- can do damage to the brakes. This is why it is very important not to fill the brake reservoir with any other liquid.

What Happens

If you accidentally fill the brake fluid reservoir with windshield washer fluid, the alcohol and water in the brakes will react with all of the components, making it unsafe to drive. Windshield washer fluid can easily ruin the calipers, master cylinder and brake hoses if driven.

How to Fix It

Do not drive the car. Driving could result in further damage. You will need to "bleed" the brake fluid, flushing the entire system. To do this, you have to make sure there is absolutely no fluid left in the reservoir before refilling with brake fluid. If you do not know how to bleed the brakes, have your car towed to the nearest mechanic.

References

• Auto Upkeep: Frequently Asked Questions
• AA1Car: Why Change Brake Fluid