How to Check for a Brake Fluid Leak in Your Vehicle

If you've ever applied your car brakes only to find them spongy and low, chances are your vehicle is leaking brake fluid. To avoid a disaster, you need to check for a possible leak. Follow these steps to check for a brake fluid leak in your vehicle.

Difficulty: ModerateInstructions

Step 1
Locate your vehicle's brake master cylinder. Generally, it is mounted in the vicinity of the firewall at the back of your engine compartment.
Step 2
Open the cylinder and check the level of brake fluid inside. The cylinder should be full. Some vehicles have a mark inside the cylinder that indicates a fill line.
Step 3
Loosen the nuts that attach the master cylinder to the brake booster and look at the seal surrounding the push rod. It will be obvious if brake fluid is leaking.
Step 4
Check your vehicle's caliper piston for leaks. If the piston seal leaks, it will leak brake fluid.
Step 5
Examine brake hoses or lines connected to the piston for cracks. Moisture or water on your caliper may indicate a brake fluid leak.
Step 6
Confirm that the cap to your vehicle's brake master cylinder is tight and that there are no leaks or signs of previous leaks.
Step 7
Drive your vehicle onto a blanket, sheet or large piece of cardboard and tap your brakes hard several times. Look for signs of a brake fluid leak on the surface.
Step 8
Watch for your red brake warning dash light to appear. This can indicate low brake fluid.