BRAKE MAINTENANCE TIPS
FOR A SAFER CAR

Why is brake maintenance important? The braking systems on our vehicles often go unnoticed until they fail, resulting in an accident or serious injury and expensive brake service costs. Without a doubt the brakes on our cars must work properly so our car stops every time we step on the brake pedal.

Interestingly enough, early model vehicles either had no brakes or had some sort of friction brake working off a lever that rubbed against the wheel or was actuated by a cable, kind of like a go-cart brake.

Better than dragging your leg on the ground Like Fred Flintstone, but not by much. These brakes were adequate at the time because there wasn’t a lot of traffic so collisions weren’t common and speeds were slow so quick stops weren’t all that necessary.

As auto manufacturers figured out how to make engines more powerful and cars go faster it became necessary to find a braking system that was more efficient and would stop a speeding vehicle in a much shorter distance.

Just as necessity is the mother of invention, increased horse-power and speed were the mother of the hydraulic braking system that continues to be used on our modern day vehicles.

The hydraulic brake system remains in use today for several reasons. It’s simple to design and manufacture, it doesn’t have a lot of moving parts and it’s very consistent in operation and reliable when properly maintained.

Despite these benefits routine brake inspection and service is still required to keep the system in proper working order. It's easy to let brake maintenance slide because we tend to not think about what's working correctly. It's only when we've ignored a maintenance item and it's beginning to wear out do we start paying attention to it.

Noted below are some key parts to hydraulic brake systems that require periodic inspection and eventual replacement.

Hydraulic Fluid: (Also known as brake fluid). A type of fluid that cannot be compressed. Usually glycol or silicone based with the purpose of transmitting hydraulic pressure from the brake pedal through the brake lines to the brake assembly at each wheel.

Brake Master Cylinder: A hydraulic cylinder that acts as a reservoir for the brake fluid. It contains two pistons that transmit hydraulic pressure to the wheel cylinders.

A Proportioning Valve: This component limits the hydraulic pressure to the rear brakes to keep them from locking up prematurely.

Power Brake Booster: Can be operated by a vacuum or hydraulically to provide assistance in applying the brake pedal, making it easier to push the brake pedal down in a controlled manner.

Disc Brake Caliper: A device with a piston that squeezes the brake pad against the brake rotor when hydraulic pressure is applied. Most cars and trucks have them on the front wheels. They are becoming standard on all four wheels on newer vehicles.

Brake Rotor or Disc: A flat, usually cast iron disc that is mounted on the wheel hub and rotates with the wheel. It has a brake pad on each side and slows the vehicle through friction with the brake pads that are pushed against it when the brake pedal is depressed. These components need to be inspected frequently since they are subject to wear from being in frequent contact with the brake pads during braking.

Brake Pads: Heavy, flat steel plates with blocks of friction material glued to them that are mounted in the brake caliper on each side of the rotor. These components are also part of a regular brake inspection service since they are subject to wear from being in contact with the rotors during braking.

Brake Wheel Cylinder: A small cylinder mounted in the brake drum that is operated by hydraulic pressure. When the brake pedal is pushed the wheel cylinder pushes the brake shoes against the brake drum which stops the vehicle.

Brake Drum: A large drum made from cast iron that is mounted on the wheel hub and rotates with the wheel. This component also needs to be part of the brake inspection due to it being subject to wear from rubbing against the brake shoes during braking.

Brake Shoe: Friction material that is fastened to a curved shoe and mounted inside the brake drum. When the brake pedal is depressed the brake shoe is pushed by the wheel cylinder and makes contact with the inside of the brake drum causing the vehicle to slow down and stop. This is another component subject to wear due to frequent contact with the brake drum. It should also be part of the entire brake system maintenance program.

Antilock Brake Systems:

For maximum braking performance the tires on your car need to be slipping just a little bit against the pavement. What this means is that during emergency braking the tires need to be rotating right up to the point of locking up and sliding. This maximizes the braking action and stopping ability. During an emergency stop it’s basically impossible for the everyday motorist to manually do this. When you slam on the brakes in an emergency the brakes lock up, you usually lose some steering control of the car and don’t stop very quickly either.

So, the need for more efficient and safer emergency stopping was the mother of the ABS (antilock braking system). The ABS system is controlled by a computer that sends signals to the hydraulic components of the system to rapidly open and close the valves that operate the individual brakes that are starting to lock up at any given moment. This prevents you from locking the brakes up no matter how hard you press on the brake pedal.

Brake System Maintenance:

Brake shoes and brake pads will eventually wear out and need to be replaced. Part of their life expectancy depends on the type of material they are composed of and the particular manufacturing process they undergo. The driving style and conditions under which the vehicle is driven, and the size and weight of the vehicle are also factors that determine how long these components will last. Since these two brake system components do wear out brake inspection should be done on a regular basis.

Visually inspecting the brake pads can usually be done without removing the wheels. A good time to perform a brake system inspection is during every oil change or at least every three months. Many brake pads are made with a small metal tab that comes in contact with the rotor when about 20 percent of the pad surface is left. When this occurs you will hear a squealing or chirping noise telling you its time for the pads to be replaced. Brake shoes can be inspected by removing the wheel. After the wheel is removed the shoes and drum can be inspected for wear.

The rotors will also wear out over time and can usually be inspected without removing the wheels. When the brake pads are replaced the rotors are normally either replace or turned (machined down to where the braking surface is smooth again). If there is significant wear to the extent that the rotor thickness will be below the recommended dimension after machining, or there is deep scoring of the rotor it is necessary to replace the rotor with a new one.

The most common symptom of brake rotor wear is vibration in the brake pedal and/or steering wheel when the brakes are applied. This vibration is caused by variations in the rotor's surface as it turns in contact with the brake pads. If this occurs it’s time to take a look at the condition of the rotors and pads.

Brake Fluid.

It’s also necessary to check and maintain the proper level and condition of the brake fluid. Checking the level is easy. Just look at the fluid level in the brake master cylinder and be sure it is between the high and low marks. It’s normal for the fluid level to drop over time as the brake pads wear. If you notice a drop in the fluid level don’t just top it off to the full mark. Inspect the brake system to be sure there isn’t a leak somewhere or the brake pads are needing replacement.

Many motorists are not aware that brake fluid will degrade over time which is why checking the condition of the brake fluid should also be a regular part of brake system maintenance. Most brake fluids are glycol base and will absorb moisture. Moisture promotes corrosion in any of the components it comes in contact with. It also lowers the boiling point of the brake fluid which can contribute to “brake fade.”

For instance, you are driving along and need to slow down so you push on the brake pedal and notice that it travels closer to the floor each time you push on it. You end up having to pump the brake pedal to generate enough hydraulic pressure to slow or stop the vehicle. This is caused by the brake fluid in the calipers and wheel cylinders beginning to boil.

When the moisture in the fluid hits the boiling point it turns into vapor which is compressible. This causes a reduction in the hydraulic pressure applied to the pads or shoes.

Proper brake fluid maintenance includes replacing the brake fluid periodically with brake fluid meeting the proper specifications for the vehicle. Many manufacturers will give a brake fluid change recommendation in the vehicle manual. If they don’t a good rule of thumb is to replace the brake fluid every two years or 30,000 miles. This simple step will go a long way to keeping your brake system in top working condition.

Remember, a complete brake inspection should be part of your routine car maintenance checkup. Brake service jobs can be expensive if the system is allowed to deteriorate beyond the normal wear that occurs as you drive the car.

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