Vehicle Brake Systems Guide

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There is probably no other area of vehicle repair more critical to your safety than proper brake maintenance and repair. Unfortunately, it is frequently overlooked. Many do-it-yourselfers will spend countless hours and expense upgrading their vehicle’s engine, interior, and body, while neglecting the safety of their vehicle. The guidelines and instructions in this article will help keep you from making the same mistake.

How often you need to check/service/replace your brakes depends on several factors. These include your driving habits and the type of miles you put on your vehicle, the quality of replacement parts used, proper installation, etc. This article provides an overview of the basics of vehicle brake maintenance and replacement.

The brake system is extremely critical to your personal safety. Additionally, brake systems vary greatly between vehicle makes and models. For these reasons, it is strongly recommended that you refer to an appropriate service/repair manual for your vehicle (such as those published by “Chilton” or “Haynes”) whenever checking, servicing and/or replacing brakes.

These manuals are easily available online, through major book retailers, or from some vehicle dealership parts departments. They may also be available for checkout from your local library if you do not wish to purchase one.

There are two types of brake systems in use today: Disc brakes and Drum brakes. A vehicle may use one type of brakes exclusively, or a combination of both. Disc brakes, being superior and significantly more “user-friendly”, have become increasingly popular. They are standard equipment on the front wheels of most vehicles, and are appearing on the rear of more vehicles every year.

Drum brakes, when maintained correctly, are nearly as good as disc brakes, and are still used on the rear of most vehicles. Unfortunately, drum systems are generally more complex than disc brakes and often require special tools for removal an installation.

Conversely, disc brake systems are typically simple, have little or no maintenance required between changes, and are easy to maintain and repair. Since the front brakes of a vehicle are responsible for the majority of the braking action (up to 80% on some applications), this articles deals primarily with the components and maintenance of disc brake systems.

Disk Brakes

One benefit of disc brakes is that they typically include a built-in “low” brake pad material indicator. This indicator is a simple piece of metal that extends from the side of the brake pad. This indicator operates similar to a tuning fork. When the brake pad wears to a pre-determined point, the indicator nears the spinning rotor, and begins to vibrate.

This vibration generates a sound similar to screeching, and typically occurs at low speeds when the brakes are NOT being applied. Any noise emitted from the brakes while they are being activated is an indication of a serious problem, and the brake system should be checked IMMEDIATELY.

A typical disc brake system consists of the following components:

• Rotor - a large circular piece behind the wheel
• Caliper - Looks like a clamp attached over the rotor, typically in the 11 or 2 o’clock position.
• Brake Pads - One pad is located on each side of the rotor; the pads are held in place and activated by the caliper.

Disc Brake Maintenance:

• Loosen the lug nuts on each wheel. DO NOT REMOVE THE LUG NUTS.
• Raise the vehicle, and safely support with jack stands.
• Working one wheel at a time, remove the lug nuts and tire, and set aside.
• Remove the caliper-retaining bolts.
  
  NOTE: A special tool may be required to remove the retaining bolts.
• Separate the caliper from the rotor. To prevent damage to the brake hose, use “mechanics wire” or a metal clothes hanger, and “hang” in a location that is free of obstructions.
•  Inspect the brake pads and verify that they are wearing evenly. If the pad material is less than 5 millimeters thick, replace the brake pads with new OEM-quality replacement parts (refer to step 9).
• Remove the rotor.
  
  ● On newer vehicles, this is accomplished by gently pulling the rotor off the hub.
  ● On older vehicles, it may be necessary to remove a large center nut and cotter pin secureing the rotor in place.
  
  NOTE: If your vehicle’s brakes use this configuration, the center nut must be tightened with a torque wrench during installation to the specific torque setting for your vehicle. A repair manual is required to obtain the correct torque value.
  
• If the brake pads require replacement, OR, if the rotor shows any sign of major wear (i.e. grooves), you must have the rotors re-surfaced or replaced. Typically, any location that sells replacement pads can either do this for you, or recommend a local auto repair facility.
  
  NOTE: Re-surfacing the rotors ensures longer pad life, quieter brake operation, and overall better stopping ability by giving the brake pads a “smooth” even gripping surface.
• In order to replace the brake pads, you will need to “push” the caliper piston back into its housing. Many auto parts stores sell a tool specifically designed for this purpose; however, a large C-clamp and flat object (such as a small block of wood) will work in most cases, as described below:
  
  ● Place flat object over the piston.
  ● Position the C-clamp over the center of the flat object (DO NOT allow the C-clamp to directly touch the piston).
  ● Slowly tighten the C clamp.
  
  NOTE: On some disc brake systems, the caliper piston must be “turned in” (similar to a bolt). Typically, these types of installations are found on rear disc brake, and can be identified by the notches in the caliper piston. Refer to your vehicle’s repair manual for proper procedures when working with these types of systems.
  
• Replace brake pads with new units. Place the caliper back over the replaced/re-surfaced rotor, and install the caliper bolts.
• Place the wheel back on vehicle and attach lug nuts only until snug. Lower the vehicle, remove the jack, and then tighten lug nuts to the correct torque value (refer to your vehicle’s repair manual).

Once installed, you should “break in” the brake pads to ensure long life and proper function. The most common way to accomplish this is typically referred to as the “4 – 40 – 40” method. To do this, accelerate the vehicle to 40 MPH, then activate the brakes and attempt to stop in 40 feet. By doing this correctly four times, your brake pads should be properly broken in.

Drum Brakes

Maintenance and repair of drum brake applications will require use of the vehicle’s service manual. This is due primarily to the higher number of moving parts in these systems, particularly springs that must be inspected and installed correctly in order to ensure proper operation.

One other recommendation when working with drum brakes is to remove both wheels, but only repair/replace brakes for one side at a time. This way, if you become confused as to the proper configuration of the springs and associated hardware, you can view the other side in its complete form as a reference.

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