Boxster Project: Brakes: Introduction

Porsche has endowed the Boxster with a great braking system. I'd give the brakes a very high rating in three important areas:

1. Brake fade is a term that describes something that happens when brakes are asked to work hard repeatedly. The brake pedal feel becomes softer and softer, and the brakes have less and less stopping power. It happens usually due to heat buildup in the system, either from the pads getting so hot that their ability to grab the rotor diminishes, or from the brake fluid nearest the caliper heating to the point of boiling, creating air bubbles in the brake lines. Brake fluid is not compressible, but air is highly compressible: air in the brake lines means that when you press the brake pedal your initial effort does nothing but compress the air rather than move the piston. While the Boxster is not immune to brake fade, especially on the most demanding race tracks under repeated lapping, its braking system resists fade much longer than many other high performance cars. Thank you Porsche and Brembo!

2. Pedal feel obviously refers to how the brake pedal feels under your foot. I put pedal feel into three categories. Compared to the Boxster, most cars have a very soft pedal, which does not give a feeling of confidence. Other cars, sometimes with a performance-oriented image, have a harder, grabbier pedal, but with less distance between "no braking" and "full braking", making the brakes feel strong at first touch but not actually giving you as much control. The Boxster has a pedal feel that is firm but not grabby, yet has a nice amount of room for controlling (modulating) the amount of pressure you deliver to the pedal with your foot.

3. Serviceability is not all that important in a typical street car, but if you do your own work, and especially if you take your car to the track and will have to do it often, you'll appreciate how easy it is to work on the Boxster's brakes, and how quickly you can do the job. It makes the standard shop rates charged by the dealer seem outrageous. I suspect that this kind of design comes from Porsche's endurance racing experience, in environments where it is critical to be able to replace worn brake parts as quickly as possible. You want your pit crew to be able to slap new rotors and pads on in a few moments so that you can get back on course without a lot of down time.

With that in mind, let's walk through a complete Boxster brake service: parts, pads, rotors, and fluid. You can also use these instructions to do just the pads, or just the fluid, or just the rotors. I'll describe the process in the order you could use if you were doing the entire service.