Brakes: We need them. They, along with tires, are crucial to your car's performance and your survival while driving. What happens when your brake light warning turns on? This is a 2008 Porsche Boxster S and today we're going to examine the elements of brake service and why they're important.
The brake warning light illuminated and the owner of this Boxster paid us a visit to find out why. We lifted the vehicle and removed the wheels.
This is a close-up of the brake components with the wheel removed. The rotor is connected to and turns with the wheel/tire. When you press the brake pedal, hydraulic pressure is applied to the pads via the caliper and the friction created by the pads clamping the rotor from both sides stops the vehicle.
Here is another view of the caliper and the pads. As you can see, there is a pad on each side of the rotor surface that is pressed upon by the caliper in the direction of the arrows. When the pad material wears below a specified threshold, the rotor will contact the sensor which will turn the light on in the instrument cluster.
If the light is on and the pads are visibly worn to the point that the sensor is contacting the rotor, we know the pads will need to be replaced. The rotor is then measured for thickness and inspected for cracks, wear and damage. If it is beyond it's wear tolerances, it must be replaced.
The holes in this rotor identify it as being cross-drilled. These holes allow heat and gases to escape during braking, effectively reducing heat which will ensure optimum braking performance and increase the lifespan of your components. When inspecting these rotors, it's important to check for cracks around the holes. Porsche fits cross-drilled rotors to a wide array of their cars. If your car was not originally equipped with them, they can be retrofitted and serve as an excellent upgrade!
Here is another photo of the brake components with the sensors, pins and anti-rattle springs removed. The weights attached to the pads help absorb vibration.
Here the caliper has been removed from the vehicle and cleaned. The pads and silencers have also been removed.
The caliper to spindle mating surfaces are cleaned to ensure proper fitment. If the surfaces are dirty, the caliper may not fit squarely which can cause issues down the road. This step is often overlooked during a brake service.
The rotor is removed from the hub, which is also cleaned thoroughly. The hub is the component that the rotor and wheel are fitted to. If there is any dirt or debris present on it's mounting surface, this can cause lateral runout which will wear the brakes and tires unevenly and may exhibit vibration issues.
A close-up of a clean hub. Hubs can become worn or damaged as a result of impact during a collision or simply running over a curb or pothole. If the hub becomes bent, it cannot be straightened and must be replaced. Inspecting, replacing(if necessary) and even cleaning a hub is an important step often overlooked in diagnosis or repairs.
Overview of the replacement parts is shown here. Often times, the bolts that connect the brake caliper to the spindle are found to be bent. The force applied to them during braking causes fatigue and they eventually cause the caliper's position to shift. We replace these bolts during every brake service to ensure the caliper is seated where it is supposed to be.
This is a close-up of the new silencer and the new pad. The silencers are adhesive backed and stick to the back of the pad. The two dowels(shown) fit in to the inside of the caliper pistons when installed. Their purpose is to reduce vibration and thus reduce braking noises such as grinding and squealing. Porsche recommends that they be replaced when pads are replaced. Most repair shops, even dealerships, don't adhere to this advice and reuse old silencers. We replace them every time new brakes are fitted to your car. A Porsche not only requires new silencers, Porsche's deserve new silencers.
A new rotor is fitted and the caliper is mounted with new bolts and torqued to specification.
Side view of the caliper in position. Ready for silencers to be installed. Note the holes in the caliper pistons.
New silencers have been installed in the calipers. The adhesive backing has been peeled up. We're ready for pads, ladies and gentlemen!
Pads installed, along with the sensors, anti-rattle springs and pins. The springs place constant tension on the pad backing plates to aid in reducing vibration and noise. The sensors wiring is routed and fastened to prevent rubbing on other components.
Porsche recommends replacing brake fluid once every two years.
This concludes the briefing in a standard ATX Autosport brake service! Remember- not all brake jobs are created equal. The work that one repair facility performs may differ from another. Consider all elements in the equation: the type and quality of the service, parts/labor, desired out come-all of these are important.