Boxster Project: Brakes: Changing Brake Rotors
by Trygve Isaacson, copyright c2000-2002
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Tools
OK, we're assuming you've already gone through the first part of [ Changing Brake Pads ] so your brake pads have been removed and you are ready to pull the caliper off so that you can replace the rotor.
The basics for replacing rotors:
- 10mm hex key socket for caliper bolts (for use with torque wrench)
- 10mm wrench or socket to remove the brake line attachment screw
- new caliper bolts (2 per caliper, get them at the Porsche parts counter)
- anti-seize paste
- Philips head screwdriver(an impact driver is highly recommended)
- and of course the new rotors
Removing the Caliper
1. Using the 10mm wrench, detach the little screw and bracket that holds the section of metal brake line between the caliper and the flexible brake line to the suspension strut. You need to do this because when you remove the caliper this section of metal brake line will have to move with it. See figure A.
Figure A. The brake line bracket bolt, colorized green. We're peeking behind the caliper. You can see the top caliper bolt close to the camera, and the inner bleeder screw above it. The bolt is farther back, at the suspension strut.
2. Using the 10mm hex head socket, remove the two big long caliper bolts. As you back them out, the caliper itself will come loose from the hub. You'll need a big wrench to break them loose, and after a few turns you can use a smaller wrench to back them out quickly. When they're all the way out you can move the caliper aside and set it on something behind the rotor (a box or something like that). See figures B, C, and D.
Yes, it's that simple.
Figure B. Removing the upper caliper bolt.
Figure C. Removing the lower caliper bolt.
Figure D. The caliper off the car and moved aside, resting on a box. It's still connected by the brake line.
Removing the Rotor
The rotor is held in place with real force by the lug bolts, which came off with the wheel. So what's left are two little Philips head screws that hold it in place lightly. Simply take these two little screws out and the rotor comes off. However, you need to be careful with these screws because they are somewhat soft and they can become stuck in place from corrosion and heat. I strongly recommend that if the screws don't come off with a little bit of easy force, you use an "impact driver" to unscrew them. You strike the impact driver with a hammer, and it applies a twisting force while under impact, such that the screw gets loosened without stripping it. Then you can easily unscrew it the rest of the way. See figures E and F.
Figure E. Striking the impact driver to loosen the little rotor screws. There are two screws holding the rotor on the hub.
Figure F. Once loosened by the impact driver, you can remove the two screws easily.
That's it, the rotor comes right off the hub. See figures G, H, and J.
Figure G. Pulling the old rotor off the hub.
Figure H. The hub, sans rotor.
Figure J. Closeup of the hub.
Installing the New Rotor
1. Put a light coating of anti-seize paste on the inside of the rotor, where it comes in contact with the hub. If you look at your old rotor, you'll see the outline of the hub and you can use that as a guide.
Figure K. Outside rotor surfaces.
Figure L. Inside rotor surfaces.
Figure M. Anti-seize paste where the new rotor will contact the hub.
2. Hold the rotor in place against the hub and screw in the two little Philips screws. Don't screw them in too tight. You want them to come out easily next time, and they serve no purpose other than to hold the rotor in place while you have all this stuff taken apart and the lug bolts aren't there to do the job. See figures N, P, and Q.
Figure N. Placing the new rotor in position on the hub.
Figure P. Tightening the first rotor screw while holding the rotor in position.
Figure Q. Tightening the other rotor screw. All done with the rotor!
Replacing the Caliper
1. Before you put the caliper back, this is a good time to inspect the piston seals. Over time they can dry out and start to crack. I'm not sure what amount of cracking is OK and not OK. I understand that it's possible to get the outer seal parts and even replace them yourself, but that the inner seals may require a more elaborate caliper rebuild by the dealer.
Figure R. Close inspection of the caliper piston seals.
2. Grab the two new big caliper bolts and put them through the mounting holes in the caliper. Place the caliper into position and start screwing in the bolts using the 10mm hex head socket. Once they're in fully, torque them to 63 ft-lbs.
Figure S. Putting the caliper back in place to be bolted on.
Figure T. Holding the caliper while starting the caliper bolts.
Figure U. Screwing in the caliper bolts.
Figure V. Torquing the caliper bolts to 63 ft-lbs.
3. Using the 10mm wrench, re-attach the screw and bracket that hold the brake line to the suspension strut. See figure W.
Figure W. Re-attaching the little bolt that holds the brake line to the suspension.
OK, you're done with the rotor and caliper, and are ready to go back and finish up with [ Installing the New Pads ].
Or: [ next: Bleeding and Flushing ]
Or: [ back to contents ]
