Service Manual2004 FRONT DISC BRAKES

SECTION 4D

FRONT DISC BRAKES

DESCRIPTION AND OPERATION

BRAKE CALIPER

The caliper has a single bore and is mounted to the steering knuckle with two mounting bolts. Hydraulic pressure, created by applying the brake pedal, is converted by the caliper to a stopping force. This force acts equally against the piston and the bottom of the caliper bore to move the piston outward and to slide the caliper inward, resulting in a clamping action on the rotor. This clamping action forces the linings against the rotor, creating friction to stop the vehicle.

Important :

Replace all components included in the repair kits used to service the caliper.

Lubricate the rubber parts with clean brake fluid to ease assembly.

Do not use lubricated shop air on brake parts, as damage to the rubber components may result.

If any hydraulic component is removed or disconnected, it may be necessary to bleed all or part of the brake system. Refer to Section 4A, Hydraulic Brakes.

Replace the pads in axle sets only.

The torque values specified are for dry, unlubricated fasteners.

Perform the service operations on a clean bench, free from all oily material.

COMPONENT LOCATOR

FRONT CALIPER BRAKE

Front Brake Caliper Assembly
Front & Grease Pin Set
Brake Pad
Brake Pad Spring
Pin Bolt
Piston Boot
Piston
Piston Seal
Caliper Bolt
Bleeder Screw

DIAGNOSTIC INFORMATION AND PROCEDURES

LINING INSPECTION

Raise and suitably support the vehicle.
Remove the front wheel. Refer to Section 2E, Tires and Wheels.
Visually check the linings for minimum thickness and wear.

Measure the thickness.

Important : The minimum thickness to the inner or outer pad is 2 mm(0.0787 inch).

Install the pads in axle sets only.
Install the front wheels. Refer to Section 2E, Tires and Wheels.
Lower the vehicle.

FRONT DISC BRAKE ROTOR INSPECTION

Thickness variation can be checked by measuring the thickness of the rotor at four or more points around the circumference of the rotor. All measurements must be made at the same distance in from the edge of the rotor.

A rotor that varies by more than 0.03 mm(0.0012 inch) can cause pedal pulsations and/or front end vibration during brake applications. A rotor that does not meet these specifications should be refinished to specifications or replaced.

During manufacturing, the brake rotor and the tolerances of the braking surface regarding flatness, thickness variation, and lateral runout are held very close. The maintenance of close tolerances on the shape of the braking surfaces is necessary to prevent brake roughness.

In addition to these tolerances, the surface finish must be held to a specified range. The control of the braking surface finish is necessary to avoid pulls and erratic performance and to extend lining life.

Using a commercially available dial indicator, check lateral runout as follows:

Notice : permissible lateral runout is a maximum 0.03 mm(0.0012 inch). If lateral runout exceeds the specification, ensure that there is no dirt between the rotor and the hub and that contact surfaces are smooth and free from burrs.

Position the transaxle in NEUTRAL.
Remove the front wheel. Refer to Section 2E, Tires and Wheels.
Fasten the brake rotor to the wheel hub with two wheel nuts.

Fasten a dial indicator to the brake caliper.
Set the gauge probe tip to approximately 10 mm (0.39 inch) from the outer edge of the brake rotor, perpendicular to the disc and under slight preload.
Remove the dial indicator and the wheel nuts that connect the rotor to the hub.

Important : Since accurate control of the rotor tolerances is necessary for proper performance of the disc brakes, refinishing of the rotor should be done only with precision equipment.

Refinish the rotor, if required, with precision equipment. Discard the rotor if it fails to meet the above specifications after refinishing.
Install the front wheel. Refer to Section 2E, Tires and Wheels.

REPAIR INSTRUCTIONS

ON-VEHICLE SERVICE

SHOE AND LINING (BRAKE PADS)

Removal and Installation Procedure

Raise and suitably support the vehicle.
Remove the front wheels. Refer to Section 2E, Tires and Wheels.
Remove the lower guide pin bolt of the caliper assembly.

Important : Caliper assembly removal is not necessary to service the brake pads.

Installation Notice

Tightening Torque

27 N•m (20 lb-ft)

Take care not to damage the piston seal when the retaining frame is pulled down.

Pull the caliper piston housing up.
Remove the brake pads.

Installation Notice

Measure the minimum brake pad thickness. Refer to "Lining Inspection" in this section.
Always change the all pads on one wheel at a time.

CALIPER ASSEMBLY

Removal and Installation Procedure

Raise and suitably support the vehicle.
Remove the front wheels. Refer to Section 2E, Tires and Wheels.
Remove the nut and seal rings attaching brake hose to the caliper.
Disconnect the brake hose and plug the openings in the caliper and the brake hose to prevent fluid loss and contamination.

Installation Notice

Tightening Torque

40 N•m (30 lb-ft)

Bleed the brake system. Refer to Section 4A, Hydraulic Brakes.
Check the brake system for leaks.

Remove the caliper mounting bolts from the steering knuckle, and remove the caliper assembly.

Installation Notice

Tightening Torque

95 N•m (70 lb-ft)

Notice :

Do not move the vehicle until a firm pedal is obtained or improper braking action will result.

Repeatedly press the brake pedal to bring the pads in contact with the rotor.

FRONT DISC BRAKE ROTOR

Removal and Installation Procedure

Notice : Do not hang the caliper assembly from the brake hose. Any resulting internal hose restriction will impede uniform braking action.

Important : To guarantee uniform braking on both sides, both rotors must have identical surfaces regarding smoothness and scoring depth. For this reason always replace both rotors.

Remove the caliper assembly without disconnecting the brake hoses. Refer to "Caliper Assembly" in this section.
Remove the rotor-to-front wheel hub detent screw.
Remove the front disc brake rotor.

Installation Notice

Tightening Torque

4 N•m (3 lb-ft)

Inspect the rotor Refer to "Rotor Inspection" in this section.

SPLASH SHIELD

Removal and Installation Procedure

Remove the front disc brake rotor. Refer to "Front Disc Brake Rotor" in this section.
Remove the bolts for splash shield from the steering knuckle.
Remove the splash shield.

Installation Notice

Tightening Torque

5 N•m (4 lb-ft)

UNIT REPAIR

CALIPER OVERHAUL

Disassembly and Assembly Procedure

Remove the caliper assembly. Refer to "Caliper Assembly" in this section.
Remove the guide pin bolts, connecting the caliper piston housing to the retaining frame.

Installation Notice

Tightening Torque

27 N•m (20 lb-ft)

Remove the front pad brake set, including the pad springs, from the caliper. Refer to "Shoe and Lining (Brake Pads)" in this section.
Pull out the guide pins and the rubber boots.

Important : Make sure the pad springs are properly installed.

Remove the bleeder valve protector and the bleeder valve.

Installation Notice

Tightening Torque

9 N•m (6 lb-ft)

Remove the outer seal.

Caution : Do not place fingers in front of the piston inan attempt to catch or protect it when applying compressed air. This could result in serious injury.

Important : Insert a piece of hardwood into the caliper housing interior when removing the piston.

Using compressed air, blow out the piston from housing.

Remove the inner seal from the caliper piston bore.

Installation Notice

Clean all the parts in denatured alcohol or brake fluid.
Dry the parts with unlubricated compressed air and blow out all the passages in the housing and the bleeder valve.
Inspect the piston and the caliper for scoring, nicks and corrosion. Replace the components if these elements are found.
Lubricate a new piston inner seal.
Rubber parts and retaining ring must be discarded and replaced with new parts.
Lubricate the piston with clean brake fluid.

SPECIFICATIONS

GENERAL SPECIFICATIONS

Application		Unit	Description
Rotor	Outer Diameter	mm (inch)	256 (10.08)
	Thickness	mm (inch)	24 (0.95)
	Discard Thickness	mm (inch)	22 (0.87)
	Runout	mm (inch)	0.03 (0.0012)
Caliper	Pad Thickness	mm (inch)	11 (0.4331)
	Pad Discard Thickness	mm (inch)	2 (0.0787)
	Diameter of the Piston	mm (inch)	57 (2.2441)

FASTENER TIGHTENING SPECIFICATIONS

Application	N•m	Lb-Ft	Lb-In
Caliper Guide Pin Bolt	27	20	-
Brake Hose-to-Caliper Bolt	40	30	-
Steering knockle-to-Caliper Mounting Bolt	95	70	-
Rotor-to-Front Wheel Hub Detent Screw	4	3	35
Splash Shield Bolt	5	4	44
Bleeder Valve	9	6	80