A Short History of the Brake
Back in the early days of the automobile ” hitting the brakes ” tended to be an iffy proposition at best and downright dangerous at worst. Early braking systems were not much better than the foot to the ground method used by Fred in The Flintstones. These systems often used a hand lever to press a block of wood to the rim of the vehicle’s wheel to slow the vehicle down. Another system featured a pointed sprang, or spike, which would drop down and dig into the road when a lever was pulled. Still another braking system consisted of a boat anchor, which the early motorist would drop overboard in hopes of stopping the vehicle. Later motorcars had strips of leather wrapped around one of the wheel hubs, which would, when a lever was pulled, tighten around the hub to slow the vehicle down. This wraparound brake performed poorly, if at all, when wet.
Later, in the early 1920s, if you were the proud owner of a Model T Ford and had to stop in an emergency you might have had to shift the car into reverse to bring it to a quick stop. The motorcars of those years were equipped with drum brakes only on the rear wheels. It was not until 1928 that four-wheel hydraulic drum brakes (brake shoes that expand internally against the inside of a rotating drum attached to the wheel) became the standard for most automobiles. But drum brakes, when used repeatedly, have a tendency to ” fade ” (when the heat built up from stopping distorts or glazes the drum and no longer allows the pads to provide friction against the drum), leading to a temporary loss of braking power. Disc brakes, the solution to this problem, were discovered in the 1950s. With disc brakes, brake pads press against a heat-conducting metal disc or rotor, which helps to dissipate the heat that builds up. Now cars use drum brakes only on the rear wheels and disc brakes on the front or on all four wheels. The most modern technology has about half of the cars on the road equipped with two or four wheel computerized anti-lock braking systems (ABS). Anti-lock brakes work by sensing when a vehicle’s brakes are on the verge of locking-up, then automatically pumping the brakes (up to twenty times a second) when the vehicle’s driver ” stands ” on the brake pedal, thus helping to prevent the vehicle from skidding. You can tell the vehicle’s anti-lock brakes are working when you ” stand ” on the brake pedal in a hard stop and the pedal pulsates or kicks under your foot.
Brake Problem Warning Signs
The following are signs of trouble with your brakes and you should have a Brentwood Tire Company Brake Service Technician examine your brake system as soon as possible.
• BRAKE OR ABS WARNING LIGHT STAYS ON — If your brake or ABS warning light stays on or comes on intermittently while driving it may be due to low brake fluid level or a brake fluid leak, a defective parking brake switch, a fault in your ABS system, or some other fault in the electrical system. In any case you should have your vehicle examined immediately if this problem arises.
• GRABBING BRAKES — If your brakes grab when lightly applied this may be caused by grease or oil contaminated linings or a loose or broken brake part.
• GRINDING OR CRUNCHING — If you hear a loud grinding or crunching sound when you apply your brakes it means your brake pads (in disc brakes) or brake shoes (in drum brakes) are worn to the point where the metal backing of the pad or shoe is grinding against the metal of the disc or drum. In this case have your brake pads checked and replaced immediately.
• HIGH OR HARD PEDAL — A high or hard brake pedal feel may mean your power braking system is inoperative due to a bad brake booster. You should have your brake system examined immediately if this problem arises.
• LOW OR SOFT PEDAL — If your brake pedal feels low or soft and you have to pump the pedal to get the car to stop, it may mean either you have air in the brake lines or you are low on brake fluid. In either case you should have your brake system thoroughly examined for leaks immediately if this problem arises.
• LOW, BUT FIRM PEDAL — A low, but firm pedal feel may mean your rear shoes or parking brake may need adjustment.
• PULLING LEFT OR RIGHT WHEN BRAKING — If your vehicle pulls left or right when braking it may indicate under-inflated tires, a bad suspension component, a leaking wheel cylinder, a plugged brake line, or a stuck wheel cylinder or caliper piston. In any case you should have your vehicle examined immediately if this problem arises.
• REAR WHEELS LOCK WHEN BRAKING — If your rear wheels lock when braking you may have grease or oil contaminated brake linings, out of round or oversized brake drums, faulty hydraulic control valves, or loose wheel cylinders. Have your brakes examined by a Service Technician immediately if this problem arises.
• SHAKING OR HOPPING PEDAL — If your brake pedal shakes or hops under normal braking it may indicate that your brake drum is out of round or your rotor is warped or out of round.
• SQUEAKS — Unless you have a family of mice living in your car if you hear squeaks when you apply your brakes the problem may be that a brake pad is loose or rusty, causing it to vibrate and squeak when the brakes are applied.
• STICKING BRAKES — If you feel your brakes sticking it may be because your brakes are not releasing properly which may lead to total brake loss. Have your brakes examined by a Brake Service Technician immediately if this problem arises.
• BRAKES SCREECH, BANG, SCRATCH, CHATTER, GROAN, SQUEAL, ETC. — Please have your brakes checked immediately. Your rotor may be glazed or the calipers may need to be replaced. Any unusual sound coming from your brakes should be inspected.