Checking Thickness of Brake Pads

Printed in Germany - II, 1991

Removing and installing brake pads Note

The brake pads are changed in the usual manner known from other Porsche models fitted with four-piston fixed calipers. This is why only a short description of the operations Is given. Please make sure the following is observed at all times:

use correct brake pad quality (refer to spare parts catalog).

Replace damping plates or vibration dampers with new parts whenever the brake pads are changed.

The damping plates and vibration dampers are protected by an adhesive sheet. Pull off this protective sheet before fitting the pads.

Do not grease the pad backing plates (rear of brake pads).

Extend warning contact lead at brake caliper and pull warning contact out of the brake pad plate.

Note

Replace warning contacts if the lead has been ground through to the bare wire. If grinding marks are limited to the plastic section of the warning contact, the warning contact may continue to be used.

Pull out brake pads using a brake pad slide hammer puller, absolutely observing the following points:

Expand brake pads complete with damping plates or vibration dampers, respectively. If this is not possible (depending on the degree of wear of the brake pads), use a spatula to separate the damping plates / vibration dampers from the brake backing plate prior to removal of the pads. Push back brake pads as far as possible in both cases, using the piston retracting tool. If required, start by drawing off some brake fluid from the reservoir.

Removal

Compress spreader spring in the middle and disengage from its mounting. At the same time, i.e. before starting to compress it, press spreader spring towards brake disc in the retainer plate area (to take the load off the spring). This prevents damage to the retainer plate.

Installation

If required, use piston retracting tool to push piston back into home position.

Clean seating and guiding surface of the brake pads inside the caliper with some white spirits and a cylinder brush or special brush.

Make sure the dust seals of the brake pistons are not damaged.

Insert new damping plates or vibration dampers, respectively, into the pistons. Since the damping plates and vibration dampers are protected by an adhesive sheet, this protective sheet must be pulled off before the pads are fitted.

Fit brake pads. Be sure to use the correct pad quality.

Note

The brake backing plates (back of brake pads) must not be greased. To prevent the brake pads from corroding in the brake caliper, apply a thin grease coat to the seating and guide surfaces.

Use Optimoly HT (Cu paste) or Plastilube (supplied by Messrs. Schillings, P.O. Box 1703, D-7080 Aalen) for this purpose.

Grease mounting eyelets of the spreader spring with Optimoly TA or Plastilube.

If required, fit a new spreader spring, making sure the flat side points towards the brake disc.

Make sure the spreader spring engages correctly (arrow). Do not force the spring into position as this may cause the retainer plate to be damaged.

Brake disc t

Outside

Outside

Fit warning contact lead and warning contact. The spreader spring may have to be disengaged once again to allow the warning contact lead to be fitted.

Actuate the brake pedal several times forcefully with the vehicle stationary to allow the brake pads to move to their normal operating position.

Then check brake fluid level and top up if required.

Running in the brake pads

New brake pads require a running-in period of approx. 200 kms (120 miles). It is only after this mileage that they reach optimum friction and deceleration values. Except for emergency situations, avoid hard braking from high speeds during this time.

Adjusting the brake pushrod Note

Adjustment of the brake pushrod is only required in the following cases:

when the brake booster is replaced if the clevis of the brake pushrod has been removed if the pushrod or the clevis has been rotated.

1103-46

The brake pedal does not have a stop. As there is no resting position for the brake pedal if the brake pushrod is adjusted correctly, the correct built-in free play in the brake booster is provided for. If the brake pedal is actuated manually a pushrod play of approx. 10 mm may be felt at the pedal plate of the brake pedal.

1103-46

2. Tighten lock nut.

3. Check adjustment of stop light switch again (refer to page 46-6).

Readjusting the pushrod at the joint clevis causes the position of the brake pedal to be changed. The adjustment of the stop light switch must then be checked as well.

Adjusting

1. Adjust length of brake pushrod by turning the clevis. The length (dimension a) must be 207 + 1 mm when measured from the contact surface of the booster on the spacer (mounting flange) to the center of the clevis pin.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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