New brake service safety and technologies

Q: We used to turn away pad replacements on cars with rear disc brakes because of having to retract the caliper pistons. Is there a tool to make this easier?

A: You certainly don't want to send this lucrative service work away. Numerous companies offer tools that help to rotate the caliper pistons back into the housing, thereby providing the clearance needed for new pad installation. Some kits fit a wide range of cars such as Audi, Chrysler, Ford, GM, Honda, Jaguar, Mazda, Mini Cooper, Mitsubishi, Nissan, Saturn, Subaru, Toyota, Volkswagen and Volvo. Remember to always follow the exact steps outlined in a reliable shop manual when servicing rear disc brake systems.



Q: To save labor, we're considering an on-car brake lathe. Are there any new developments in this area?

A: Yes, one of the latest breakthroughs in on-car lathes features faster and easier setup to enhance overall service. A two-way adjustable compensation adapter that works with computerized compensation adjusts for lateral runout of the hub in seconds. This capability allows for shops to refinish rotors within OEM specifications in a matter of minutes.

Other advancements include ACT (Anti-Chatter Technology) to minimize finish irregularities by virtually eliminating chatter. ACT oscillates the speed of the lathe to prevent the build-up of vibration that can occur on any fixed-speed lathe, ensuring a smooth surface finish. ServoDrive technology also enables you to vary the spindle speed and rotational torque of the lathe while in operation. This unique ability allows “on-the-fly” speed adjustments without compromising the final surface finish. Also, reverse rotation proves beneficial when servicing some vehicles with limited-slip differentials, which produce excessive drag on the driveshaft, preventing normal lathe operation.


Q: A shop manual calls for checking an ABS wheel speed sensor’s bias voltage. What is it and how do we measure it?

A: The speed sensor’s bias voltage enables fault detection in the sensor circuit and also raises the voltage to help reduce signal interference. The voltage varies depending on manufacturer, but is often the typical 5-volt reference found in other computer circuits. You can measure bias voltage easily with your Digital Multimeter (DMM) by following the connection points outlined in service information.


Thanks for checking out this month’s Tool Q&A column. Remember, this is your column, because it’s based off your questions. So, let PTEN know what’s on your mind when it comes to tools and equipment.