In addition to thrumming, your brake pedal can give you other indications that your car's braking system might need examining.
A mushy pedal, one that goes practically to the floor before engaging the brakes, could indicate worn pads or a problem with the hydraulic system, such as air in the line, an air leak or a brake fluid leak. To check for a fluid leak, put an old white sheet or piece of light cardboard under the car overnight. In the morning, examine any fluid that collects. Brake fluid will be practically clear and the consistency of cooking oil.
The opposite of a mushy pedal is one that causes the brakes to grab immediately at the slightest touch. This could indicate an unevenly worn rotor, dirty brake fluid or contamination of the fluid by moisture. You can solve such a problem with a relatively inexpensive change of fluid that you could do yourself or have done at your mechanic's shop.
Finally, if stopping the car seems akin to Fred Flintstone putting his feet through the bottom of the car to bring it to a halt, you might have a brake line obstruction or a problem with the vacuum system. Both situations would make the brake pedal extremely hard to operate and require immediate servicing.
For lots more information about your brakes, check out the next page.