Rear Without PCCB
Removing and installing rear brake pads
1. Remove wheel.
Removing rear brake pads
The brake calliper must be removed in order to remove the brake pads. Do not open the brake hydraulic system while doing this!
Brake fluid level
Before removing the brake pads, a small amount of brake fluid must generally be removed by suction (from the reservoir). This depends on the brake fluid level and the amount of wear on the brake pads.
1. Remove warning contact wire at the brake calliper and expanding spring -arrows-. Remove warning contacts from brake pads -arrows-.
Remove brake calliper at the wheel carrier (fastening screws -1-). Do not open the brake hydraulic system while doing this!
To remove the brake pads, place the brake calliper in a suitable place (e.g. on a hydraulic lift.).
Rear brake calliper
Removing brake pads
2. Pull the brake pads -1- out of the brake-pad guide pins -2-.
Brake-piston damping plate (connecting plate)
Generally, the brake-piston damping plates -3- (if fitted) are also removed at the same time (these are bonded to the brake pad backing plate). If this is not the case, remove the brake-piston damping plates -3- separately.
3. Remove expanding spring on the brake calliper -arrows-.
Expanding spring
Installing rear brake pads - 911 Turbo
1. Before installing the brake pads, check the amount of wear on the brake discs.
2. Push the brake pistons back to their original position using the brake piston resetting fixture NR.144.
3. Fit a new expanding spring on the brake calliper.
Do not deform expanding spring when inserting it. Make sure that the expanding spring is positioned perfectly in the brake calliper -arrows-.
Expanding spring
Information
^ Replace the brake calliper fastening screws each time the pads are changed.
^ Brake-piston damping plates (connecting plates with vibration balancers) are used in the grey cast-iron brakes on the rear axle of the 911 Turbo (status as at July 2008). Use new brake-piston damping plates (connecting plates with vibration balancers).
Brake-piston damping plate (connecting plate with vibration balancers)
Brake pad fitted
^ Important information for installing brake-piston damping plates (connecting plates): The connecting plates must be seated perfectly in the brake pistons and the brake pads must be positioned correctly on the guide pins (prescribed guide pin position). The connecting plates must also be bonded securely to the brake-pad backing plates. When test driving the vehicle, do not brake too severely at the beginning to ensure subsequent/optimal driving comfort.
4. Fit new brake-piston damping plates (connecting plates with vibration balancers) -3- into the pistons. Observe the following procedure:
4.1. Cut the protective film on the connecting plates -3- closely around the screw heads -1- (using a suitable knife blade). As a result, the protective film can be pulled off safely (make sure there are no bits of protective film left on the bonding surface because these will prevent full-area contact).
Fitting brake-piston damping plate (connecting plate)
4.2. Lightly grease surface areas of the aluminium vibration balancers -2- on the connecting plates with brake cylinder paste before fitting.
4.3. Carefully insert connecting plates -3- with protective film as far as they will go into the pistons without trapping the O-rings.
4.4. Clean the backs of the brake pads by giving them a quick wipe with a suitable solvent (to remove any dust and grease).
4.5. Pull protective film completely off the connecting plates.
When doing this, make sure not to touch the bonding surfaces or the cleaned backs of the brake pads with your fingers.
5. Fit brake pads.
5.1. Position brake pads before pressing them onto the bonding surface of the connecting plates.
First fit the brake pads -1- onto the guide pins and press them towards the brake disc run-off side -5- until the brake pads are touching the guide pins (curved surface) -broken arrow-.
Then press the brake pads -1- straight onto the connecting plates. Do not pretension the expanding spring -2- while doing this. This means that the pads must be positioned radially on the pins when bonding them, -arrows at the sides- (with the spring force of the expanding spring -2-).
1 - Brake pad (position straight on the guide pin/arrows)
2 - Expanding spring
3 - Ventilation valve (top)
4 - Run-in side of brake disc (rear axle)
5 - Run-off side of brake disc (rear axle) Positioning brake pads (rear axle)
Pfeil dunn - Brake disc turning direction (forward)
Pfeile - Required brake pad position on guide pin Broken arrow = Position on guide pin (by pressing the pad towards the brake disc run-off side). Two arrows at the sides = Position on guide pin (with spring force of expanding spring)
6. Fit brake calliper on the wheel carrier. As a general rule, use new fastening screws -1-.
Observe the following procedure:
Screw in fastening screws -1- (only fit loosely at first).
Immediately after fitting the brake calliper, fit the brake pads on the brake discs. To do this, press the brake (brake pedal) with average brake pressure for approx. 5 seconds to allow the brake-piston damping plates (connecting plates) and brake pads to connect securely.
Using slight brake pressure (approx. 10 bar/brake pedal pressed slightly), tighten the fastening screws -1- to 85 Nm (63 ftlb.). A second fitter is required or use a brake pedal support.
Then insert the warning contact wire and warning contacts -arrows-.
Rear brake calliper
Brake fluid level
7. Check the brake fluid level and correct it if necessary. The brake fluid level must be between the MIN and MAX markings.
Bedding in the brake pads
New brake pads require a bedding-in period of approx. 200 km (125 miles). Only then do they achieve their maximum braking effect. The slightly reduced braking effect must be compensated for by increased pressure on the brake pedal. The same also applies after a brake disc change.
Subsequent work
1. Fit wheel.