Overhaul
Removal
1. Remove one wheel nut, mark the wheel relative to the stud, and remove the remaining wheel nuts. Remove the road wheel and tire assembly.
2. Carefully remove the caliper retaining spring (1). Remove the pad wear sensor multi-plug from the retaining clip, then disconnect the harness multi-plug (2).
3. Loosen the caliper feed pipe union nut. Remove the caliper securing bolt dust caps then remove the socket head securing bolts (3). Remove the caliper from the carrier
4. Remove the brake pads (4),
5. Fully unscrew and remove the caliper from the brake hose. Install a suitable plug to the brake caliper hose to prevent loss of fluid and the ingress of dirt. Use of a Hose Clamp will help reduce the loss of fluid.
6. Unscrew the carrier securing bolts and remove the carrier.
NOTE: If both front calipers have been removed from the car, take care not to mix up left and right hand caliper bodies. Remove all brake dust from the caliper, carrier and disc. Thoroughly clean the pad abutment areas, avoid damaging the piston and dust cover.
WARNING: Brake lining dust can contain asbestos which if inhaled, can damage your health. always use a vacuum brush to remove dry brake lining dust. never use an air line.
Disassembly
1. Eject the piston by gently applying low pressure air to the inlet port. Use a piece of wood to prevent the piston from being damaged.
2. The piston dust cover cannot be removed until the piston has been ejected. Remove the piston, pull out the dust cover and extract the piston seal from the bore.
3. Remove the bleed screw and clip from the caliper body.
Cleaning and Inspection
CAUTION: When cleaning brake components never use gasoline. Use of gasoline, or other mineral based fluids can prove dangerous.
4. Examine all the components for signs of wear, damage and corrosion. Pay particular attention to the piston and cylinder bore. Remove body corrosion with a wire brush or wire wool. No attempt should be made to clean a badly corroded or scored cylinder bore.
5. Inspect the caliper securing bolts, ensure that they are not corroded or seized and that the caliper is free to move on them. If the bolts are difficult to remove or are corroded, they must be replaced together with new dust covers.
CAUTION: No attempt should be made to clean corroded bolts.
Reassembly
1. All parts must be in good working order. Where doubt exists new parts should be fitted.
CAUTION: Ensure that working surfaces and hands are clean. Use only brake fluid of the correct specification (DOT 4) to lubricate the new seals when installing.
2. Lubricate the new piston seal, carefully fit to the inner groove of the piston bore.
3. Lubricate, and fit the dust cover over the piston. Continue pulling the dust cover along the piston, extending the convolutions, until the inner sealing lip is almost at the end of the piston.
4. Install the piston and dust cover assembly into the piston bore. Locate the dust cover lip in the groove of the piston bore. Gently but firmly push the piston fully home through the dust cover.
NOTE: Ensure that the dust cover is not trapped between the piston and the bore, and that the inner lip of the dust cover is correctly located in the inner groove in the piston bore.
5. Refit the bleed screw to the caliper body.
6. Lubricate the securing bolts and bores with the special grease, Molykote 111 supplied in the Service Kit.
CAUTION: Do not use any other type of grease.
7. Fit and align the carrier to the vertical link. Tighten the carrier securing bolts TO 102-128 NM (75-94 FT LB).
Installation
1. Place the caliper to the front of the carrier then remove the plugs from the caliper and hose.
2. Install but do not fully tighten the caliper feed hose. Remove the hose clamp.
3. Ensure the caliper piston is fully retracted then fit the brake pads to the caliper.
NOTE: If the pads are worn to the minimum thickness, new pads must be fitted.
4. Reposition the caliper/pad assembly to the carrier then install and tighten the caliper securing bolts to 131-175 Nm (97-129 ft lb).
5. Install and fully seat the dust covers.
6. Final tighten the feed hose union nut to 7-12 Nm (5-8.8 ft lb).
7. Install and fully seat the caliper retaining spring. Connect the brake pad sensor harness multi-plug then reposition the plug into the retaining clip. Ensure that the harness cannot foul or chafe.
8. Install the road wheel.
9. Bleed the brake system. Service and Repair
NOTE: It may be necessary to run the engine to give power assistance to the brake pedal.
10. Pump the brake pedal several times to move the brake pads to their operating positions.
WARNING: Application of the brake pedal must be carried out, as the brake will not operate efficiently until the pads are correctly positioned.
11. Apply pressure to the brake pedal and inspect all connections.