How Do You Check Brake Fluid?

The process of checking brake fluid is determined by vehicle make and model. While exact steps can vary, checking brake fluid generally requires identifying the primary fluid basin, where fluid levels are determined by pre-measured fill lines. Vehicles manufactured before 1980 may require manual removal of a brake fluid check line. Vehicle-specific operating manuals describe exact steps.

  1. Locate the brake master cylinder

    The master cylinder is typically located on the driver's side toward the rear of the engine. Its appearance may vary, but generally this item is made of clear or white plastic with a removable cap. The words "brake fluid" may be found on the cylinder or on its cap.

  2. Review fluid levels

    Most vehicles are equipped with visual line markers on the exterior of the brake master cylinder, which read "full" and "low" or "maximum" and "minimum." Visually inspect the fluid in comparison to these lines. If fluid is near or above the "full" line, no further action should be taken. Fluid levels near the "low" line must be filled.

  3. Fill with brake fluid

    Before topping off brake fluids, determine the type of fluid the vehicle requires. Most vehicles use DOT 3 or DOT 4 fluids. If you're unsure which type your car needs, review the owner's manual. Once the appropriate fluid is gathered, remove the plastic cap and fill to the "full" or "maximum" fill line.