Buyer’s Guide: How to Buy Brakes

Kinds of Brake Systems

Hydraulic Brake Systems

Hydraulic brake systems, as the name implies, use hydraulic fluid for braking.

Single-Circuit Hydraulic Brake Systems: In single-circuit brake systems, when the brake pedal is pressed, a piston in the master cylinder helps transfer the non-compressible brake fluid to the brake caliper/wheel cylinder. In drum brake systems, the brake caliper forces the brake pads to squeeze against the brake rotor. In disc brake systems, the wheel cylinder pushes the brake shoes towards the brake drum.

Dual-Circuit Hydraulic Brake Systems: These brake systems control the braking with two circuits. When the brake pedal is pressed, the first circuit sends a signal to an on-board computer. The on-board computer then calculates the required brake pressure and instructs the second circuit which includes the master and slave cylinders to perform the requisite braking action.

Dual-circuit hydraulic brake systems are efficient as they consider factors like the vehicle's speed to determine the ideal brake pressure. These brake systems are commonly employed in luxury automobiles.

Brake-by-wire Systems

Brake-by-wire systems are electronically-controlled braking systems. Brake-by-wire and dual-circuit hydraulic systems work similarly but are different in their design. Brake-by-wire systems use electronic wires to activate the brake system whereas the dual-circuit hydraulic systems use hydraulic fluid to activate the brake system.

Parking Brakes

Parking brakes are also known as hand brakes or emergency brakes. These brakes can be used to stop the vehicle when the standard brake system fails.

Anti-lock Braking Systems (ABS)

These systems are superior to standard braking systems. Anti-lock braking systems employ sensors to monitor the speeds of the car's wheels. The main advantage of anti-lock braking systems, as inferred from the name, is that they prevent the wheels from locking up in case of emergency stops, thereby preventing any serious damage to the driver and vehicle. Anti-lock braking systems are monitored by an on-board computer. If the computer senses any possibility of locking up, it vigorously pumps the brakes to prevent the vehicle from skidding.

Air Brake Systems

Air brake systems are generally found in heavy automobiles such as trucks, buses and trailers. These systems employ air instead of hydraulic fluid. Air-brake systems have a compressor that compresses air to provide the required brake pressure.

Causes of Brake Failure

• A low level of brake fluid in the system is one of the common causes of brake failure.
• The piston seals in the master cylinder may get damaged, failing to transfer the fluid with the optimal pressure.
• Brake pads/shoes tend to wear out over time, failing to stop the brake drum/disc from spinning.
• Brake drums/rotors can also develop hot spots on their surface due to prolonged exposure to heat.
• The brake booster can also become defective, forcing the brake system to operate with a lesser brake pressure.
• Oil or grease from other car parts can enter the brake system and play spoilsport with the entire braking performance.

Symptoms of Failing Brakes

• Bad break pads will emit a squealing or grinding noise while braking.
• Failed braking linkages may cause your vehicle to pull towards one side.
• Worn-out brake shoes or pads exhibit a hard or spongy pedal.
• Bad brake drums/rotors will cause your vehicle to wobble while braking.
• A damaged master cylinder will not let the brake pedal return to its normal position.
• Problems in the anti-lock braking systems will turn on the ABS light in your vehicle's dashboard.
• The car will have a longer braking distance after the pedal has been pressed.

Maintenance

• Checking the level of the brake fluid on a regular basis is one of the basic processes in maintaining a brake system.
• Cleaning/flushing the brake system periodically is also advisable.

Why is the OEM number important for buying an auto part?

Vehicle manufacturers designate the parts employed in their vehicles with an OEM (Original Equipment Manufacturer) number. Assigning an OEM number to parts helps identify them easily. OEM parts are usually produced by the manufacturers themselves or by a third party trusted by the manufacturers. There are two ways to get the right replacement part at BuyAutoParts.com: You can enter your car's year, make and model or your part's OEM number.

The OEM number can usually be found on the part itself. If you are not sure of your part's OEM number, you can provide your VIN (Vehicle Identification Number) to your dealership and get the right OEM number from your dealer.