Front Brake Caliper Overhaul (GXP)
Front Brake Caliper Overhaul (GXP)
Disassembly Procedure
Important: Fabricate blocks of soft wood with the following dimensions which are to be used to perform the procedure below:
* BLOCK ONE: 19 mm (3/4 in) X 51 mm (2 in) X 51 mm (2 in)
* BLOCK TWO: 19 mm (3/4 in) X 51 mm (2 in) X 127 mm (5 in)
1. Inspect the brake fluid level in the brake master cylinder reservoir.
Warning: Refer to Brake Fluid Irritant Warning (Brake Fluid Irritant Warning).
Caution: This brake caliper is coated with a specialized paint. Use care when handling and servicing to ensure the paint does not get chipped or scratched. Clean any brake fluid from painted surfaces with denatured alcohol, or equivalent, as soon as possible.
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution (Brake Fluid Effects on Paint and Electrical Components Caution).
Note: Do not completely empty the brake master cylinder reservoir.
Note: The brake fluid level must be midway between the maximum brake fluid level marking and the minimum brake fluid level marking.
2. If required, use J 23738-A to remove some brake fluid until the brake fluid level is midway between the maximum brake fluid level marking and the minimum brake fluid level marking.
Danger: To avoid any vehicle damage, serious personal injury or death when major components are removed from the vehicle and the vehicle is supported by a hoist, support the vehicle with jack stands at the opposite end from which the components are being removed and strap the vehicle to the hoist.
Warning: Refer to Safety Glasses Warning (Safety Glasses Warning).
3. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle (Service and Repair).
4. Remove the front wheel. Refer to Tire and Wheel Removal and Installation (Service and Repair).
5. Install 2 opposite wheel nuts (1), with the flat side of the wheel nut against the brake rotor to retain the brake rotor to the wheel hub.
Caution: This brake caliper is coated with a specialized paint. Use care when handling and servicing to ensure the paint does not get chipped or scratched. Clean any brake fluid from painted surfaces with denatured alcohol, or equivalent, as soon as possible.
6. Remove the front brake pads from the brake caliper. Refer to Front Disc Brake Pads Replacement (Base and GT) (Front Disc Brake Pads Replacement (Base and GT))Front Disc Brake Pads Replacement (GXP) (Front Disc Brake Pads Replacement (GXP)).
7. Remove the brake caliper from the vehicle. Refer to Front Brake Caliper Replacement (Base and GT) (Front Brake Caliper Replacement (Base and GT))Front Brake Caliper Replacement (GXP) (Front Brake Caliper Replacement (GXP)).
8. Drain the brake fluid from the brake caliper into an approved container.
Note: Use plastic vise caps or similar to protect the brake caliper mounting bosses from marring.
9. Suitably support the brake caliper in a vise.
Caution: Use clean cloths to pad interior of caliper housing during piston removal. Use just enough air to ease the pistons out of the bores. If the pistons are blown out, even with the padding provided, it may be damaged.
Note: Make a note matching the brake caliper bores with their respective brake caliper pistons.
10. Place BLOCK TWO over 2 adjacent pistons and secure in place with a non-marring C-clamp.
11. Place BLOCK ONE over one of the opposing piston bores and secure BLOCK ONE in place with a non-marring C-clamp.
12. Use clean workshop towels to pad the interior of the brake caliper housing before removing the brake caliper piston.
13. Remove the brake caliper piston by directing low pressure compressed air into the brake caliper brake fluid inlet hole. If the dust boot seal came off the brake caliper piston, reinstall the dust boot seal to the brake caliper.
14. Move BLOCK ONE over the empty piston bore and secure it in place with a non-marring C-clamp.
15. Use clean workshop towels to pad the interior of the brake caliper housing before removing the second piston.
16. Remove the brake caliper piston by directing low pressure compressed air into the brake caliper brake fluid inlet hole. If the dust boot seal came off the piston, reinstall the dust boot seal to the brake caliper.
17. Repeat steps 10 through 17 for the adjacent brake caliper pistons.
Note: Do not scratch or mar the painted surfaces or brake caliper piston bore.
18. Remove all the dust boot seals (1) using a suitable flat-bladed tool.
19. Discard the dust boot seals (1).
Caution: Do not remove the caliper external crossover tube or separate the 2 caliper halves. If the crossover tube and/or the caliper halves are separated, corrosion and damage to the caliper may result.
20. Using a suitable wooden or plastic tool, remove the brake caliper piston seals (3) from the piston bores.
21. Discard the piston seals (3).
22. Remove the brake caliper bleeder caps (1).
23. Remove the brake caliper bleeder valves (2).
24. Remove the brake caliper (4) from the vise and clean the brake caliper (4) with denatured alcohol, or equivalent.
25. Dry the brake caliper piston bores with non-lubricated filtered air.
26. Make sure that the external crossover pipe (5) and the internal fluid ports are clean and free of obstructions.
Note: DO NOT clean the brake caliper piston bores by honing or using abrasive materials.
27. Inspect the brake caliper cylinder bores and piston seal counter-bores for scratches, cracks, pitting, and/or corrosion.
28. If the brake caliper piston bores are marred, cracked, or pitted, or if corrosion cannot be cleaned with denatured alcohol, replace the brake caliper assembly (4).
Assembly Procedure
Note:
* Replace all the components included in the repair parts kit supplied to service the brake caliper.
* Lubricate the rubber parts with NEW DOT 4 or NEW Super DOT 4 brake fluid to assist in the assembly of the rubber parts.
* If any hydraulic components has been removed or disconnected, bleed the hydraulic brake system.
* The torque values specified are for dry, non-lubricated fasteners.
* Perform the service operations on a clean bench, free from all mineral oil materials.
Note: Make sure the dust boot seal (3) is correctly seated in the dust boot seal groove of the brake caliper pistons (4),.
1. Install the NEW piston dust boot seals (3) over the brake caliper pistons (4).
2. Lubricate the NEW piston seals (5) with NEW DOT 4 or Super DOT 4 brake fluid from a clean, sealed brake fluid container.
Note: Make sure that the piston seals (5) are not twisted.
3. Install the lubricated, NEW piston seals (5) into the brake caliper bore seal grooves.
4. Apply a thin coat of NEW DOT 4 or NEW Super DOT 4 brake fluid from a clean, sealed brake fluid container, onto the brake caliper piston bores and the outer surface of the brake caliper pistons (4).
5. Match the pistons of one side of the brake caliper with their respective bores and install the brake caliper pistons.
Note: Do not force the brake caliper pistons into the brake caliper bores. The pistons should slide easily into the brake caliper bores.
6. Carefully press the pistons (4) and dust boot seals (3) of the inserted pistons all the way into the brake caliper bores by hand.
7. Make sure that the dust boots (3) and pistons (4) of the inserted pistons are fully seated in the brake caliper by placing BLOCK TWO over 2 adjacent piston bores and apply light pressure with a non-marring C-clamp..
8. Repeat steps 5 through 7 for the opposite brake caliper pistons.
Caution: Refer to Fastener Caution (Fastener Caution)
9. Install the brake caliper bleeder valves (2) and tighten to 14 Nm (124 lb in).
10. Install the brake caliper bleeder valve caps (1).
11. Install the front brake pads to the brake caliper. Refer to Front Disc Brake Pads Replacement (Base and GT) (Front Disc Brake Pads Replacement (Base and GT))Front Disc Brake Pads Replacement (GXP) (Front Disc Brake Pads Replacement (GXP))
12. Install the brake caliper to the vehicle. Refer to Front Brake Caliper Replacement (Base and GT) (Front Brake Caliper Replacement (Base and GT))Front Brake Caliper Replacement (GXP) (Front Brake Caliper Replacement (GXP)).
13. Remove the 2 opposite wheel nuts (1) from the wheel studs.
14. Install the front wheel. Refer to Tire and Wheel Removal and Installation (Service and Repair).
15. Lower the vehicle to the ground.