Brake job on Porsche Boxster S
After the last several months of travel, holidays, work, and family obligations, I found some time to get back to some projects that make use of my wrench collection. New year’s day, Jim and I tackled the brakes and rear axles on the wife’s 2002 Porsche Boxster S. Although now ten years old, the car has less than 50K miles on it and still had the factory brakes. Like many modern cars, the brake pads are now equipped with electronic sensors which indicate when the pads need to be changed – a big improvement over the mechanical “squealers” that were attached to the pads of cars in the past.
While we had the car on the lift, we noted that the rubber boots at both ends of each rear axle had split all the way through and were leaking grease. Torn boots not only allow the axle grease to escape, but dirt and water to enter and attack the CV joints. Left un-repaired, these would eventually start to wear and make clunking or popping noises while cornering, and would eventually fail. Best to replace them now.
We removed the wheels, brake pads, and then the calipers and rotors all the way around the car and hung the calipers from the struts using elastic cord. You could substitute wire, or some old coat hangers – anything that will support them and avoid damaging the brake hoses.
We then removed the brake rotors which were retained with two screws. We marked left and right rotors with soap stone and prepared them for resurfacing.
The rotors on the S model are cross drilled for heat dissipation and are pretty robust pieces and were not particularly stressed during my wife’s commute to work, and occasional road trips. If the car were driven hard, or used in autocross or tracked, the rotors would likely have needed replacement at this point – from wear or potentially due to warping or cracking from excessive heat.
I inspected the surface of each rotor carefully and found no micro cracks. Checking the rotors on the brake lathe, I found about 10 thousands wear on either surface, and was able to true them up removing and additional 8-10 thousandths on each face. Resurfacing, trues the face of the rotor so that it is even and square and will mate properly to the new pads. After the final cut on the lathe, I finished each rotor with a fine cross hatch pattern to eliminate any spiraling from the lathe. This helps ensure quiet brake operation as the new pads are bedded in.
With the brakes apart, it was a good time to tackle the rear axles. Use of an impact wrench speeds removal of the 6 Allen head bolts that retain each axle to the transmission. I tried the first side by hand, and wound up a bit arm weary – if you have air tools, it really helps. Next, we disconnected the sway bar end link, the strut rod at the rear of the spindle, and the lower ball joint. Getting the lower ball joint to release was a chore, but once free the spindle and strut could be swung out and up, allowing the axle to slide inward and be released. (After removing the axle nut and tapping the end of the axle with a brass hammer).
Here, the new axle is installed, the spindle back in place, the strut rod and sway bar reconnected, and the caliper and rotor back in place.