Disc Brake Rotors and Diy Brake Jobs

AC Delco Disc Brake Rotor

What’s wrong with having drum brakes? Why do they use disc brake rotors? What are the symptoms of common brake rotor problems? What do you need to know about the modern composite style equipment? The answers to these questions and more are to follow.

This page is meant to help with Diy brake jobs or to just better communicate with auto repair shops during brake service. Many of the advantages of a brake rotor can be attributed to the disk itself. The typical rotor can be a solid or ventilated type and it is made of cast-iron that can withstand high temperatures.



In the old days the brake rotor was nice and thick and could be resurfaced several times. Nowadays rotors are not as thick and are sometimes made out of composite materials.

In fact composite style rotors are growing in popularity and are found on many of today’s front wheel drive and four-wheel disc brake equipped vehicles. The rotor is attached to and rotates with a hub assembly.

If your car is equipped with composite style rotors check your vehicle specific service manual to see if they recommend trying to resurface them at all. Often manufacturers will recommend replacement of the rotor instead of the reconditioning process. Brake lathes also need some specialized accessories to do a nice job so ask the part store if they can reface composite styles.

A pulse in the brake pedal sometimes described as a vibration by the driver is a common complaint. The faster you travel the more violent it pulses. One cause of this could be a warped brake rotor.

If this symptom exists on your automobile check the rotors for run out and parallelism. A badly warped disc brake rotor in my opinion should be replaced if they are of the composite style.

Often they can be resurfaced if they are of the old-fashioned cast-iron thicker variety. Strangely enough they say the most common cause of a brake rotor to become warped and cause a pulsating brake pedal is improper tightening of the wheels lug nuts.

Over tightening of the wheel lugs but more importantly different torque settings on each lug nut can push on the face of the rotor with unequal force and over time can physically cause it to warp.

This is why mechanics are supposed to use torque sticks when using a pneumatic impact gun. For the same reasons driveway mechanics should always use a torque wrench to perform the final tightening of lug nuts. Especially if they do not want to have brake rotor problems down the road.

A ventilated rotor is cast with a web like construction between its two main friction surfaces. These webs will radiate out from the center of the rotor much like the veins of a fan.

As the rotor turns air is drawn into the rotor at its center and flows between the friction surfaces and is discharged along the outer edges.

This efficiently cools the rotor which drastically reduces the chances of brake fade caused by overheating fluid. High performance vehicles will often include special ground effects that will grab cool outside air and funnel it to the rotors air intake area. This is great for cooling the rotors under high speed braking or competition braking like road course racing or even mountain driving.

Also included in the modern design is a splash shield that protects the rotor and components from road splashes, dirt and debris that can be kicked up from the road surface.

It is also shaped to channel the flow of air over the exposed rotor surfaces. As long as the car is moving this flow of air helps to cool the rotors very efficiently.

Most splash shields cannot be removed unless the rotor and caliper are removed first. Replacement of the splash shield is necessary only when it has been damaged by road debris or accidents. Give this disc brake rotors page a bookmark or share with friends.

The information from this page works well with the other articles found on the car brakes section. Brake rotor problems are discussed a little further as well as other common car disc brakes issues.

Automotive brakes can be one of the top areas of concern for drivers. This next link takes you to an article that reviews some of the most common front brake problems from this page about disc brake rotors.

If you are wondering what else the you fix cars website has to offer the homepage is a good place to start. You can also find out how to get one on one help with Diy auto repairs.