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Replacing Porsche 911 Carrera Brake Discs
 
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Pelican Technical Article:

Replacing Porsche 911 Carrera Brake Discs

Time:

3 hours3 hrs

Tab:

$600

Talent:

***

Tools:

Phillips head socket tool, rubber mallet, socket set, micrometer

Applicable Models:

Porsche 996 Carrera models (1999-05)
Porsche 996 Turbo, GT2, GT3 (2001-05)
Porsche 997 Carrera models (2005-12)
Porsche 997 Turbo, GT2, GT3 (2007-13)

Parts Required:

Brake discs, new pads, new emergency brake shoes (if required)

Hot Tip:

Adjust your emergency brake while you have access

Performance Gain:

Better, safer braking

Complementary Modification:

Replace brake pads, emergency brake shoes, install stainless steel brake lines, install new wheel bearings

Brake discs (or rotors as they are often called) are a very important part of the braking system. The brake pads rub against the discs to create a friction force that is responsible for slowing the car down. If the rotors become too thin or develop grooves in them, then their ability to stop the car decreases.

When replacing your brake pads, you should always measure the thickness of your brake discs. If they fall below the specified value for your car, then they should be replaced with new ones. Check for grooves in the rotor, and make sure that you take several measurements of the disc in several different places. This will guarantee that you get an accurate reading. If the brake disc has a groove in it, then it should most certainly be removed and resurfaced by a machine shop or simply replaced with a new one. Discs with grooves not only brake less efficiently, but they also heat up to higher temperatures and reduce your overall braking ability.

The measurements that you take with your micrometer should be made from the center of the disc. It is common for OEM rotors to have the minimum thickness stamped on the rotor hub (as is the case with the ceramic PCCB brake option). If you can't find this information, use the following chart to determine if your rotors need to be replaced.

 TYPE Front Rotor CarreraRear Rotor CarreraFront Rotor CS4Rear Rotor CS4
 NEW 28.0 mm 24.0 mm 34.0 mm 28.0 mm
 MIN THICKNESS 26.0 mm 22.0 mm 32.0 mm 26.0 mm

If you do find that you need to replace your rotors, the process is a relatively simple one. The procedure for the front or the rear rotors is very similar, but for the sake of this project, we'll look at replacing the rears, which is slightly more complicated due to the addition of the rear parking/emergency brake. With the rear rotors, if the parking brake shoes are very worn, then you may need to back off the adjustment sprocket in order to be able to remove the rear disc (see Project 51 for more details).

The first step is to jack up the car and remove the road wheel. If you haven't already, remove the brake pads from the caliper. Refer to Project 49 on replacing brake pads for more details. The flexible rubber brake hose is attached to the trailing arm of the car via a large clip. This clip retains both the flexible line and the hard line that connects to the rear caliper. Remove this clip so that you will be able to remove the caliper without bending the hard metal brake line.

Now, unbolt the caliper from the trailing arm where it is mounted. There should be two bolts that mount the caliper and hold it in place. After you remove these two bolts, you should be able to slightly move the caliper out of the way of the disc. Exercise caution when moving the caliper around-make sure that you do not let the caliper hang from the rubber brake line, as this will most certainly damage the line.

Once you have the caliper out of the way, remove the small screw that holds on the brake disc. You will need a Phillips head socket tool for this task (you can try using a big screwdriver, but odds are the screw will be on too tight and you may end up stripping it). At this point, make sure that the parking brake is off. You should now be able to pull the disc off of the hub. If there is any resistance, use a rubber mallet to tap the brake disc off. Sometimes the disc will require some heavy smacks with your rubber mallet to get it off.

If you are having a difficult time getting the disc off, it's probably because the parking brake shoes are stuck on the back of the disc. You might need to adjust the parking brake so that it's not gripping the disc. For more information on this process, see Pelican Technical Article: Parking Brake Adjustment - Porsche 911 Carrera.

Installation of the new brake disc is a snap; simply push it onto the hub. Before you install the new disc, take a close look at your parking brake shoes and see if they warrant replacing. If you can see metal on the shoes, or if the previous owner had a hard time remembering to remove the emergency brake, then it might be a good time to replace these. After you install the new discs on both sides, you should test your parking brake and adjust it if necessary. Refer to Project 53 and Project 51 for more details.

After the new disc is installed, replace the retaining screw, reattach the caliper, and install new brake pads. Your new rotors should last a long time, and you should see an improvement in your braking after the wear-in period for your new brake pads.

The front and rear brake discs look almost identical.
Figure 1

The front and rear brake discs look almost identical. The rear brake discs have an inner "drum" area that acts as the surface for the emergency brake to press against. While all the Carreras have disc brakes at all wheels, the rear parking brake mechanism is most similar to a drum brake system. You may want to paint the inner hats and edges of the discs with some high-temp paint. This will keep them from rusting after you install them.

Before you remove your brake discs, it is important to first measure them to see if they need to be replaced.
Figure 2

Before you remove your brake discs, it is important to first measure them to see if they need to be replaced. Use a micrometer to perform the measurement. If you use a dial caliper, then you might get a false reading because the disc wears on the area where the pads make contact, not on the edges of the disc. Make sure that you take several measurements in a few different places on the disc in order to compensate for potential low or high spots.

Removal of the caliper is accomplished by unbolting the two hex bolts that mount it to the arm (yellow arrow).
Figure 3

Removal of the caliper is accomplished by unbolting the two hex bolts that mount it to the arm (yellow arrow). The caliper (green arrow) can be pushed out of the away and doesn't need to be physically disconnected from the brake line. Hang the caliper from a string or coat hanger (blue arrows) so that you don't put unnecessary tension on the rubber brake line (orange arrow).

There are two small locator screws that hold the brake disc in place.
Figure 4

There are two small locator screws that hold the brake disc in place. Use a big screwdriver or a Phillips head socket tool to remove this screw, and the brake disc should slide off of the hub. Keep in mind that the lug nuts that hold on the wheel apply the majority of the force that constrains the disc to the hubâÂ"not this screw.

The new disc can be tapped on with a rubber mallet.
Figure 5

The new disc can be tapped on with a rubber mallet. If installing the rear discs, make sure that you have your parking brake shoes adjusted away from the inside drum, or they might interfere with the installation of the disc. New discs may not be perfectly flat and may take a few hundred miles of break-in to achieve their maximum braking efficiency.

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Comments and Suggestions:
Long Islander Comments: Thanks for the tech instructions. Disc removal and reinstallation are very simple. I should note, however, that there is no way to remove the brake pad from the caliper without first removing the caliper from the disc. This is because the back of each pad has a cylinder attached to it which keeps it from being pushed out of the caliper. You need to push the pad toward the center of the caliper to clear the recess that this cylinder fits into, then you can slide the pad out. Since removing the caliper from the disc consists of simply removing the caliper bolts, this is no big deal.
February 25, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Long Islander Comments: The photo shows the caliper prior to removal with the pads already removed. Is it necessary to remove the brake pads before the caliper can be pulled away from the disc? If so, do you need to push the pads away from the disc first to give enough wiggle room? Thanks.
February 8, 2016
  Followup from the Pelican Staff: The pads come out before the caliper. Only issue may be the vibration damper holding them in. If this is happening, compress the caliper pistons until you can get it out. - Nick at Pelican Parts  
Undecided Comments: Sorry, 06 997S.
February 12, 2015
  Followup from the Pelican Staff: it is the same for 997s, For a 996, caliper to wheel carrier: 85Nm. - Nick at Pelican Parts  
Undecided Comments: What is the torque spec for the caliper bolts?
February 11, 2015
  Followup from the Pelican Staff: Not sure what vehicle you have. For a 996, caliper to wheel carrier: 85Nm, the bolts have to be replaced with new. - Nick at Pelican Parts  

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Page last updated: Wed 12/7/2016 02:32:45 AM