How to Diagnose a Brake Fluid Leak in a Car

Brake fluid is essential in making sure the braking system of your car is functioning properly. It is possible to have an internal brake fluid leak where you would not see fluid leaking from beneath your engine. Check your brake fluid levels during each oil change and also look for these telltale signs of a brake fluid leak.

Difficulty: Moderate

Instructions

1. Look for fluid leaking beneath your engine. Brake fluid is light yellow when it's new and a dark muddy brown when it's old.

2. Step on your brake pedal. If it feels spongy or soft that may be an indication of a brake fluid leak.

3. Press down the brake pedal when you stop and notice if the brake pedal begins to sink to the floor. If it goes further than normal, you may have an issue.

4. Check your dash to see if your brake warning light is on, which may also indicate a leak.

5. Locate the master cylinder in your engine. It is usually located towards the back in the center. Usually, the master cylinder will say something like "use only DOT 3 (or DOT 4) brake fluid."

6. Check the brake fluid level in the master cylinder. Fill back up to the "full" line.

7. Recheck the brake fluid in the master cylinder a few days later. If the levels have dropped, you have a leak somewhere and should have your car checked out by a mechanic.

Tips & Warnings

• Brake fluid is extremely toxic. Make sure to tightly seal any leftover brake fluid, and store out of the reach of children.
• Brake fluid is highly corrosive. Immediately wipe up any spills to prevent damage to your car.

Resources

• Figure out what is leaking from your car.