Car Brakes

From the standpoint of safety, the brakes are the most important feature of your car. Properly functioning brakes-along with tires, steering, and lighting-help ensure your safety. If I were helping anyone select a used car, I would emphasize the items pertaining to safety In preference to anything else.

Be conscious of your car’s brake action and notice any perceptible changes, such as the pedal depressing farther than usual, squeaky noises, or the wheels pulling to one side when you apply the brakes. Correct any trouble at once. Do not delay! Driving with questionable brakes that might fail in an emergency is not worth the risk.

The two kinds of brakes found on cars are drum brakes and disc brakes; either kind may be power assisted. Drum brakes have been used for many years. Such a brake consists of a round drum mounted parallel to the wheel, turning as the wheel turns. 

Inside the drum are two “shoes,” each lined with asbestos on the side facing the drum. When the brakes are applied these shoes press against the inside of the drum, which causes the wheel to slow or stop turning.

The asbestos linings eventually wear thin and must be replaced. Brakes should be relined when The lining gets thin and before the rivets are exposed, otherwise grooves will be worn in the smooth surface of the drum. If this happens, it is necessary to have the drum turned on a lathe, necessitating additional expense.

Disc brakes are a newer development. Higher priced cars often cone equipped with disc brakes on all four wheels; some less expensive have disc brakes on the front wheels and drum brakes on the rear wheels. Disc brakes are definitely superior to drum brakes; in actual use the discs dissipate heat much more rapidly. Heat is the enemy of brakes, causing wear to brake linings and pads.

A disc brake is basically a round disc, similar to a phonograph record, mounted parallel to the wheel. Pads on both sides press against the disc when the brakes are applied. This type of brake is much more dependable and has less danger of fading or giving way. Safety authorities estimate that 60 percent of stopping is accomplished by the front wheels, which is why models equipped with only two disc brakes carry them on the front wheels.

Here is a simplified description of brakes and how they work. When you push the foot pedal, pressure is applied to the brakes on all four wheels through hollow lines containing brake fluid. One line leads to the two front-wheel brakes and the other to the two rear-wheel brakes. If one line fails the other will work, so you will have brakes on two wheels at least. The braking system was designed this way as a safety feature.

Get a competent mechanic to inspect your brakes periodically for wear. The frequency of this inspection depends on terrain, traffic conditions, and your driving habits. See your Owner’s Manual for suggestions on when to have the brakes inspected. An average driver with good driving habits on terrain that is fairly level should be able to go 10,000 miles before having brakes inspected.

The results of the inspection will help you decide when to have the brakes relined or how soon they should be inspected again. The mechanic should not charge to make this inspection for you, especially if he knows he will get the job if any work is needed on the brakes. 

The front-wheel brakes get die most wear and will need relining sooner than the rear-wheel brakes. If you are told that the brakes need relining, find out if the mechanic means all the brakes or those on the front wheels only.

A reservoir mounted under the hood on the fire wall holds a supply of brake fluid. The level of brake fluid in this reservoir should be checked every time the car is serviced.

On many cars manufactured since about 1970, the brakes are self-adjusting, designed to eliminate periodic brake adjustments. Cars with drum brakes adjust themselves if you apply the brakes while the car is moving backward; disc brake adjustment is made automatically with each brake application. Refer to your Owner’s Manual to learn how your brakes are adjusted.

Some drivers carelessly drive along with one foot resting lightly on Ihe brake pedal, or they brake with their left foot (particularly on cars that have automatic transmission). Both practices are dangerous and cause unnecessary wear. Do not fall into these habits.

The emergency brake is a hand-actuated lever or a foot pedal usually located to the left in the driving compartment, though sometimes it is to the right of the driver’s seat. Your emergency brake is just that it is for emergencies and should stop the car. It should also be used to hold the car when you park on an incline. Emergency brakes slop only the rear wheels. Have your emergency brake adjusted immediately if it is not operating properly.

Power brakes have a vacuum booster that aids the braking system, enabling you to stop with much less foot pressure than you would have to use without this feature. When you push the foot pedal, you should have full braking power when the pedal is about Wi to 2 inches from the floorboard. Have your brakes checked and adjusted at once if the pedal goes down farther than that.

STEERING

The steering system is very important for your safety. Normal greasing of the car at regular intervals will help prevent trouble in the steering system. Most of the grease fittings used in a grease (lube) job are located near the front wheels and steering components. See a competent mechanic at once if steering becomes difficult or unusual.

Power steering makes for effortless steering. A belt drives the power steering pump, and it will wear out eventually. You can replace belts yourself. When the car is serviced, the lubricant level in the power steering pump will be checked.

SHOCK ABSORBERS

A shock absorber is located near each wheel, thus every car has four shocks. Sometimes the shocks are mounted within large springs. When the wheel strikes an object, such as a railroad track, a brick, or a pothole, the springs help absorb some of the bounce and keep the car from jolting the passengers. The shocks are stabilizers that prevent excessive bouncing and keep the car from swaying too much when it goes around a curve. Shocks also help support any weight placed on a car.

A shock absorber is not complicated. A piston inside a cylinder compresses air as the piston moves up and does the same thing as it moves down. The resistance of the air being compressed causes the pislon to move only when considerable force is applied.

Contrary to what some people believe, a shock absorber is not full of oil. It contains only a small amount of oil to form an airtight seal between the piston and the cylinder. Shocks generally do not wear out all at once. They gradually get weaker and weaker until it is necessary to replace them. Symptoms of worn shocks that need replacing are:

1. Excessive bouncing when your car crosses over railroad tracks or bumps, and delay in returning to a stable condition.

2. Extreme leaning on curves.

3. The wheel barely clears the ground when the bumper jack is raised all the way. (If the wheel will not clear the ground, you can solve this problem temporarily by placing the bumper jack on a block of wood, but do not delay in getting the shocks replaced.)

4. The front fender sinks low when an average person (about 150 pounds) sits on it.

5. The front tires show wear in the form of pits spaced at intervals on the tire tread.

When you know that one or more shock absorbers (often those on the front) are weak and need replacing, have all four replaced. They li;ive all seen the same number of miles and about the same number til humps.