Pad Replacement Procedure
Brake pads come in several different compounds depending on the intended application. For street use, I have found the Axxis Metalmasters do just fine. OEM pads are very good, but shed lots of dust. They cost a bit more too. Here is one of those rare cases where OEM is not always best. I would get the pads from a 928OC supporter, like 928 Specialists, 928 Int'l, or DEVEK.
Today I removed the the front and rear calipers in anticipation of replacing the pads. Really no trouble removing them; 10mm allen bolts in the front and two 19mm bolts on the rear. Having said this, what is the procedure for removing the actual pads and replacing them. Have never done this on the Porsche although I've done it on numerous other cars. I always expect some sort of "Gotcha" whenever doing a 928 anything.
Patrick L.('87 S4)
Good thing you removed the calipers as it is necessary to get the pads installed with the appropriate dampers. That is one of the "Gotchas". Often times, dampers are not used when pads are replaced and the pads may move or squeal in the caliper. I would replace the wear pad sensors at the same time. Be careful, they break easily.
1) remove pad retaining spring with channel lock pliers
2) remove wear pad sensors paying attention to their routing through the retaining spring
3) remove old pads which should have dampers on their backs
4) thoroughly clean calipers inside and out with brake cleaner
5) When dry, place new dampers in the pistons WITH the covers on and make certain they hold in place.
6) Use large "C" clamp with fender washers to push pistons (now covered with dampers) back into calipers to allow room for new pads to fit. You may want to remove some brake fluid to keep it from spilling out of its reservoir (another "gotcha")
7) Clean the back of the pad with brake cleaner
8) CHECK THE PAD PLACEMENT. Place a new pad into the carrier over the dampers (still with protective covers) to see how it properly fits into the caliper.
9) Pull the pad back out and peel back the protective cover on the damper and fit a pad into it's carrier on one side, be certain that it is placed correctly the first time as once the back of the pad touches the damper, the adhesive will do its job and adjustments are extremely difficult (don't ask how I know).
9) Now peel the dampers from the other side and fit the other pad (that has a clean back).
10) now the tough part - If the pistons have moved the pads closer together, you'll have to widen the gap between the pads to get them over the rotor. Use your best judgment on an appropriate tool to push back the pads. A "C" clamp with large contact points (spot weld on some fender washers) would work well.
11) Once the caliper is in place with the new pads, you can snug up the bolts and put in the new pad wear sensors before putting the retaining spring back in place (remember the routing of the pad sensor wire?)
12) Torque caliper bolts to spec
13) After all four are changed, now is a good time to bleed the brakes.
14) Congratulate yourself on a job well done, have a beer.
Joe Rausa '89S4
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