In this episode we want to talk about brake warning systems that tell drivers when brake pads need replacement. We will talk about brake noise and what is involved in doing a professional brake job. Then we’ll discuss a little more information about Anti-lock brakes (ABS) and Traction Control (TC) systems.
Brake Warning Sensors and Brake Noise
Brake warning sensors on cars and trucks to tell a driver their brake pads are ready to be replaced. Some brake pads have a metal tab that touches the turning rotor, causing the tab to vibrate. This vibration creates a noise like a chirp or light squeal when your foot is not on brake pedal, and you’re driving at low speeds.
Dave mentioned a situation he ran into with his son. He said music is a problem for the audible sensors. His son never heard his car’s brake warning sensors because he always had his music playing loud. The result was a new brake job that also required new rotors because the brake pads damaged them. Remember what we said in the previous episode about what can happen when pads damage rotor.
Some European and Asian cars don’t have audible warning systems. They turn a light on the dash when pads need replacement. This system uses electrical sensors built into the pads. When the sensor touches the disc brake rotor it turns on the dash light.
Professional Brake Jobs Include Specific Procedures and Correct Parts
Some car owners shop for the least expensive brake job they can find. It’s always good to get a good price for auto maintenance or repair services like brake repair. But, a cheap disc brake repair that uses poor quality parts or skimps on turning the rotors, can end up being noisy or not stop your vehicle like it should.
A professional disc brake job like we do at Tune Tech Downtown will always have turned rotors or replaced the rotors. We install the correct brake pads for your vehicle, and we buy quality brake pad kits that include new hardware.
Our brake mechanics road-test every brake job to seat the new pads to the rotors. This step is critical to having quiet brakes that stop the vehicle in a short distance. Shops that do cheap brake jobs may not use quality parts. Also they may not have professional brake mechanics that know the correct procedures for a quality brake service.
We mention in the episode the importance of using brake pads made of the correct material. Pat pointed out that there are a lot of brake pads that can fit on your car, but the material the pads are made of can be the wrong material. Pads that are too hard can cause brake noise and pads that are too soft can extend stopping distances.
One last point we make about brake noise is that improper use of your brakes like over-heating them can cause permanent damage to pads and rotors. Overheated pads get hard which can result in excess rotor wear and brake squeal when applied. The fix is usually pad replacement and turning rotors or replacing them.
Introduction to 4 Wheel Anti-lock Brakes (ABS)
Here is an introduction about what 4 wheel anti-lock brakes (ABS) do and why we need them to work properly:
- Tires that are skidding on the road cause increased stopping distances. They also take away the ability of the driver to steer the front wheels when skidding.
- Anti-lock brakes, as the name sounds, are designed to keep the brakes from “locking” or skidding on the road surface.
- They do this by watching the speed of each wheel with sensors. When a wheel starts to slow too quickly or lock, the system reduces brake pressure to that wheel to keep it from locking.
- Computers can pulse brakes quicker than we can with our foot, so we have reduced stopping distances and better steering during hard braking.
Pat presented a case study of a Dodge diesel truck that had an anti-lock brake warning light on when it came into the shop. The anti-lock brake system was working correctly but the truck had a loose wheel bearing that caused the ABS wheel speed sensor to read incorrectly and turn on the ABS warning light.
Introduction to Traction Control (TC) Systems
Here is a brief introduction to traction control systems. We said earlier that ABS is design to give good traction on slippery roads or quick stops during braking. Traction Control (TC) is designed to keep your wheels from slipping on slick road surfaces while accelerating and driving on snowy, icy or wet roads.
The TC system works in conjunction with the ABS system. If a wheel starts to slip or spin on acceleration or while driving, the TC system can engage the engine, transmission or brakes to reduce the slippage. Depending on how the vehicle is made it can:
- Reduce engine power by shutting off cylinders
- Apply the brakes at the slipping wheel
- Reduce power output at the transmission
Another note about Traction control systems is that they have a button on the dash or steering column area to turn the system off. In some conditions you may not want it to work.
Conclusion of car and truck brake systems
This wraps up our three part series on car and truck brakes. You are most likely listening to the Tune Tech Downtown – Auto Care Podcast on a smart phone. You can also listen on our website.
We hope you found this 3 part series on automotive brakes helpful. In this series we presented the importance of brake inspections, brake fluid contamination, brake warning sensors, brake system warning lights, anti-lock brakes and traction control systems.
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What you’ll learn from this episode about brake noise, anti-lock brakes and traction control
- Brake systems have brake pad warning sensors
- Brake noise is caused by high frequency vibrations of disc brake pads
- Wrong brake pad materials can cause brake squeal
- Poor quality brake jobs can cause brake noise
- Anti-lock brakes reduce skidding and improve steering on quick stops
- Traction Control systems reduce tire slip while driving and accelerating