Service Manual2004 HYDRAULIC BRAKES

SECTION 4A

HYDRAULIC BRAKES

Caution : Disconnect the negative battery cable before removing or installing any electrical unit or when a tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise noted.

DESCRIPTION AND OPERATION

GENERAL DESCRIPTION

Brake fluid should meet the DOT-3 specification. Use only clear fluid from a sealed container.

Fluid that is exposed to the air will absorb moisture. Water in the brake fluid will cause the fluid to boil and the rubber components to deteriorate.

Thoroughly clean the master cylinder reservoir cap before removing it. Do not let any dirt or foreign material fall into the fluid reservoir.

There is a brake fluid level sensor under the master cylinder reservoir. This brake system uses a BRAKE warning lamp in the instrument panel cluster. When the ignition switch is in the START position, the BRAKE warning lamp should go off when the ignition switch returns to the ON position.

The following conditions will active the BRAKE warning lamp:

The lamp should be on whenever the parking brake is applied and the ignition switch is in the ON position.
A low fluid level in the master cylinder will turn the BRAKE lamp on.

The correct brake fluid level is marked on the both side of the brake fluid reservoir. If the fluid level is below the MIN indicator mark, check the hydraulic brake system for leaks. Fix any leaks. Then refill the reservoir to the MAX indicator mark.

COMPONENT LOCATOR

BRAKE SYSTEM (ABS)

Brake Booster
Master Cylinder
ABS Module
Front Brake Hose
Rear Brake Hose
Brake Pipe

BRAKE SYSTEM (NON-ABS)

Brake Booster
Master Cylinder
Front Brake Hose
Rear Brake Hose
Brake Pipe

DIAGNOSTIC INFORMATION AND PROCEDURES

BRAKE SYSTEM TESTING

Brakes should be tested on a dry, clean, reasonably smooth and level roadway. A true test of brake performance cannot be made if the roadway is wet, greasy, or covered with loose dirt which can cause tires not to grip the road unequally. Testing also will be inaccurate on a crowned roadway because the wheels tend to bounce.

Test the brakes at different vehicle speeds with both light- and heavy-pedal pressure; however, avoid locking the brakes and sliding the tires. Locked brakes and sliding tires do not indicate brake efficiency since heavily braked but turning wheels will stop the vehicle in less distance than locked brakes. More tire-to-road friction is present with a heavily braked, turning tire than with a sliding tire.

Because of the high deceleration capability, a firmer pedal may be felt at higher deceleration levels.

There are three major external conditions that affect brake performance:

Tires having unequal contact and grip of the road will cause unequal braking. Tires must be equally inflated, and the tread pattern of the right and the left tires must be approximately equal.
Unequal loading of the vehicle can affect the brake performance since the most heavily loaded wheels require more braking power, and thus more braking effort, than the others.
Misalignment of the wheels, particularly conditions of excessive camber and caster, will cause the brakes to pull to one side.

To check for brake fluid leaks, hold constant foot pressure on the pedal with the engine running at idle and the shift lever in NEUTRAL. If the pedal gradually falls away with the constant pressure, the hydraulic system may be leaking. Perform a visual check to confirm any suspected leaks.

Check the master cylinder fluid level. While a slight drop in the reservoir level results from normal lining wear, an abnormally low level indicates a leak in the system. The hydraulic system may be leaking either internally or externally. Refer to the procedure below to check the master cylinder. The system may appear to pass this test while still having a slight leak. If the fluid level is normal, check the vacuum booster pushrod length. If an incorrect pushrod length is found, adjust or replace the rod. Check the master cylinder using the following procedure:

Check for a cracked master cylinder casting or a brake fluid leak around the master cylinder. Leaks are indicated only if there is at least one drop of fluid. A damp condition is not abnormal.
Check for a binding pedal linkage and for an incorrect pushrod length. If both of these parts are in satisfactory condition, disassemble the master cylinder and check for an elongated or swollen primary cylinder or piston seals. If swollen seals are found, substandard or contaminated brake fluid should be suspected. If contaminated brake fluid is found, all the components should be disassembled and cleaned, and all the rubber components should be replaced. All of the pipes must also be flushed.

Improper brake fluid, or mineral oil or water in the fluid, may cause the brake fluid to boil or cause deterioration of the rubber components. If the primary piston cups in the master cylinder are swollen, the rubber parts have deteriorated.

If deterioration of the rubber is evident, disassemble all the hydraulic parts and wash the parts with alcohol. Dry these parts with compressed air before reassembly to keep the alcohol out of the system. Replace all the rubber parts in the system, including the hoses. When working on the brake mechanisms, check for fluid on the linings. If excessive fluid is found, replace the linings.

If the master cylinder piston seals are in satisfactory condition, check for leaks or excessive heat conditions. If these conditions are not found, drain the fluid, flush the master cylinder with brake fluid, refill the master cylinder, and bleed the system.

BRAKE HOSE INSPECTION

The hydraulic brake hoses should be inspected at least twice a year. The brake hose assembly should be checked for road hazard damage, cracks, chafing of the outer cover, and for leaks or blisters. Inspect the hoses for proper routing and mounting. A brake hose that rubs on a suspension component will wear and eventually fail. A light and a mirror may be needed for an adequate inspection. If any of the above conditions are observed on the brake hose, adjust or replace the hose as necessary.

WARNING LAMP OPERATION

This brake system uses a BRAKE warning lamp in the instrument panel cluster. When the ignition switch is in the START position, the BRAKE warning lamp should glow and go OFF when the ignition switch returns to the START position.

The following conditions will active the BRAKE warning lamp:

Parking brake applied. The light should be ON whenever the parking brake is applied and the ignition switch is in the ON position.
Low fluid level. A low fluid in the master cylinder will turn the BRAKE lamp ON.
DDRP system is disabled. The light should be ON when the DDRP system is malfunctioning.

BRAKE LAMP WARNING CIRCUIT DIAGNOSIS

Test Description

The numbers below refer to steps on the diagnostic table.

When the ignition is turned ON, the brake lamp should initially illuminate and then dim for ABS equipped vehicles. This is done as a bulb check. On vehicles that are not equipped with ABS, the brake warming lamp should only illuminate when either the brake fluid reservoir is low or the parking is applied.
The brake fluid level switch is a normally open switch. If the BRAKE warning lamp is OFF after disconnecting the switch, the brake fluid level switch is stuck closed.
If the BRAKE warning lamp is still on after disconnecting the parking brake switch, there is a short to ground in the wire to the parking brake switch.
If the other checks have been properly performed and the BRAKE warning lamp is OFF after disconnecting the electronic brake control module (EBCM) connector, the EBCM is faulty.
If the BRAKE warning lamp dose not operate while performing any of the functions, the fault should be in the ignition feed to the circuit.
This step determines if the problem is in the ignition feed to the circuit or in the instrument cluster.
The BRAKE warning lamp should illuminate when jumper the parking brake connector to ground.
If the BRAKE warning lamp is on after jumper the brake fluid level switch terminals, the switch is faulty.

Brake Lamp Warning Circuit

Step	Action	Value(s)	Yes	No
1	Start the engine and leave it running. Is the BRAKE warning lamp always on?	-	Go to Step 2	Go to Step 18
2	Check the ABS warning lamp. Is the ABS warning lamp also on?	-	Go to Step 3	Go to Step 4
3	Use a scan tool to check for diagnostic trouble codes(DTCs) and follow the procedures for any DTCs found. Were any DTC(s) stored current or history?	-	Go to the table for the (DTCs)	Go to Step 4
4	Release the parking brake fully. Is the BRAKE warning lamp off?	-	System OK	Go to Step 5
5	Check the brake fluid level. Is the fluid level OK?	-	Go to Step 7	Go to Step 6
6	Fill the brake fluid reservoir with clean DOT-3 hydraulic fluid. Check the cap on the fluid reservoir. Start the engine and leave it running. Is the BRAKE warning lamp on?	-	Go to Step 7	System OK
7	Disconnect the wiring harness connector from the brake fluid level switch. Is the BRAKE warning lamp on?	-	Go to Step 9	Go to Step 8
8	Replace the brake fluid lever switch. Is the repair complete?	-	System OK	-
9	Connect the brake fluid level switch. Disconnect the parking brake switch. Start the engine and leave it running. Is the BRAKE warning lamp on?	-	Go to Step 11	Go to Step 10
10	Replace the parking brake switch. Is the repair complete?	-	System OK	-
11	Connect the parking brake switch. Is the vehicle equipped with ABS?	-	Go to Step 12	Go to Step 14
12	Turn the ignition OFF. Disconnect the electronic brake control module (EBCM) connector. Turn the ignition ON. Is the BRAKE warning lamp on?	-	Go to Step 14	Go to Step 13
13	Replace the EBCM. Is the repair complete?	-	System OK	-
14	Turn the ignition OFF. Connect the EBCM connector. Check for a short to ground in the wiring between the instrument cluster terminal B9 and the brake fluid level switch. Is the problem found?	-	Go to Step 17	Go to Step 15
15	Check for a short to ground in the wiring between the instrument cluster terminal B9 and the parking brake switch. Is the problem found?	-	Go to Step 17	Go to Step 16
16	Check for a short to ground in the wiring between the instrument cluster terminal B9 and the EBCM connector terminal B3. Is the problem found?	-	Go to Step 17	Go to Step 18
17	Repair the wiring harness as needed. Is the repair complete?	-	System OK	-
18	Check the brake lamp after doing each of the following functions: Apply the parking brake Remove the cap from the brake fluid reservoir. On vehicles equipped with ABS, command the lamp on using a scan tool. Does the BRAKE warning lamp operate for all of these conditions?	-	System OK	Go to Step 19
19	When the operations listed in step 18 were performed, the brake warning lamp did not function. Did the BRAKE warning lamp fail to light for all of the operations listed in step18?	-	Go to Step 20	Go to Step 27
20	Turn the ignition OFF. Inspect the fuse F16. Is the fuse OK?	-	Go to Step 22	Go to Step 21
21	Replace the fuse F16. Is the repair complete?	-	System OK	-
22	Inspect the BRAKE warning lamp bulb. Is the bulb OK?	-	Go to Step 24	Go to Step 23
23	Replace the bulb. Is the repair complete?	-	System OK	-
24	Disconnect the instrument cluster connector. Turn the ignition ON. Measure the voltage at the instrument cluster connector terminal B9. Dose the voltage measure within the value specified?	11-14 V	Go to Step 25	Go to Step 26
25	Turn the ignition OFF. Repair the open in the instrument cluster. Is the repair complete?	-	System OK	-
26	Turn the ignition OFF. Repair the open in the wiring between the instrument cluster connector terminal B9 and the ignition switch. Is the repair complete?	-	System OK	-
27	Apply the parking brake again. Dose the parking brake warning lamp operate with the parking brake applied?	-	Go to Step 28	Go to Step 30
28	Remove the brake fluid reservoir cap. Dose the parking brake warning lamp operate with the cap from the brake fluid reservoir removed?	-	Go to Step 29	Go to Step 30
29	Check for an open between the instrument cluster connector terminal B8 and the EBCM connector terminal B3. Is the problem found?	-	Go to Step 17	Go to Step 13
30	Turn the ignition ON. Disconnect the parking brake switch. Jumper the parking brake switch connector terminal to ground. Is the BRAKE warning lamp on?	-	Go to Step 10	Go to Step 31
31	Turn the ignition OFF. Repair the open in the wiring between the instrument cluster connector terminal B8 and the parking brake switch connector terminal. Is the repair complete?	-	System OK	-
32	Disconnect the brake fluid level switch. Turn the ignition ON. Jumper the brake fluid level switch connector terminal. Is the BRAKE warning lamp on?	-	Go to Step 8	Go to Step 33
33	Turn the ignition OFF. Connect a test light between battery positive and the wiring harness terminal of the brake fluid level switch. Is the BRAKE warning lamp on?	-	Go to Step 34	Go to Step 35
34	Repair the open in the wiring between ground and the brake fluid level switch. Is the repair complete?	-	System OK	-
35	Repair the open in the wiring between the instrument cluster connector terminal B8 and brake fluid level switch. Is the repair complete?	-	System OK	-

REPAIR INSTRUCTIONS

ON-VEHICLE SERVICE

MANUAL BLEEDING THE BRAKES

Removal and Installation Procedure

Remove the booster reserve by applying the brakes several times with the engine off until all the reserve is depleted.

Important : If the master cylinder is known or suspected to have air in the bore, then it must be bend before any wheel cylinder or caliper is bend.

Fill the master cylinder reservoir with brake fluid. Keep the master cylinder reservoir at least one-half full during the bleeding operation.

Disconnect the brake line at the top of the master cylinder.
Allow the brake fluid to fill the master cylinder until it begins to flow from the port.
Connect the brake line at the top of the master cylinder.

Slowly push and hold the brake pedal

Loosen the brake line at the top of the master cylinder to purge the air from the cylinder.
Tight the brake line, as in Step 5, and then release the brake pedal slowly. Wait 15 seconds before proceeding to the next step.
Repeat Steps 6-8, including the 15 seconds wait, until all the air is removed from the master cylinder bore.
Tighten the brake line fitting.

Installation Notice

Tightening Torque

16 N•m (12 lb-ft)

Notice : Care must be taken to prevent the brake fluid from contacting any painted surface to prevent damage to the paint finish

After the air has been removed at the top connection, bleed the master cylinder at the side connection in the same manner as with the top connection.

Important : For vehicles equipped with a non-antilock braking system, the bleeding sequence is as follows: right rear, left front, left rear, and right front. For ABS vehicles, refer to Section 4F, Antilock Brake System for the correct sequence and bleeding procedure.

Attach a transparent tube over the bleeder valve. Allow the tube to hang submerged in the brake fluid in a transparent container

Slowly push and hold the brake pedal one time. Avoid rapid pumping of the brake pedal.
Remove the bleeder valve dust cover and loosen the bleeder screw to purge the air from the cylinder.
Tighten the bleeder screw.

Installation Notice

Tightening Torque

9 N•m (6 lb-ft)

Slowly release the brake pedal. Wait 15 seconds before proceeding with the next step.

Important : Rapid pumping of the brake pedal pushes the master cylinder secondary piston down the bore in a manner that makes it difficult to bleed the system.

Repeat Steps 13-16, including the 15 seconds wait, until all the air is removed. It may be necessary to repeat the sequence 10 or more times to remove all the air.
Locate the front bleeder caps.
Proceed to bleed the front brakes following the appropriate sequence, beginning with step 13.
Check the brake pedal for sponginess. Repeat the entire bleeding procedure to correct this condition.
Replace the bleeder valve dust cover.

FRONT BRAKE HOSE

Removal and Installation Procedure

Raise and suitably support the vehicle.
Disconnect the brake line fitting nut from the brake hose support bracket on the wheel housing on each side of the vehicle.
Remove the E-ring retainer.

Installation Notice

Tightening Torque

16 N•m (12 lb-ft)

Disconnect the brake hose from the "C" bracket on the strut assembly.

Remove the bolt from the brake caliper.
Remove the seal rings and the brake hose.

Installation Notice

Tightening Torque

40 N•m (30 lb-ft)

Bleed the brake system. Refer to "Manual Bleeding the Brakes" in this section.
Check the brake system for leaks.

REAR BRAKE HOSE

Removal and Installation Procedure

Raise and suitably support the vehicle.
Disconnect the brake line fitting nuts from the brake hoses at the body and the rear axle brackets.

Installation Notice

Tightening Torque

16 N•m (12 lb-ft)

Bleed the brake system. Refer to "Manual Bleeding the Brakes" in this section.
Check the brake system for leaks.

Remove both brake hose E-ring retainers.
Remove the brake hoses from the brackets.

STOPLAMP SWITCH

Removal and Installation Procedure

Disconnect the negative battery cable.
Separate the stoplamp switch from the connector.
Remove the stoplamp switch nut.
Turn the stoplamp switch connector assembly counterclockwise and remove it from the brake pedal bracket.

BRAKE PEDAL

Removal and Installation Procedure

Remove the lower instrument trim panel. Refer to Section 9E, Instrumentation/Driver Information.
Remove the stoplamp switch. Refer to "Stoplamp Switch" in this section.

Disconnect the spring retaining clip and the pin from the brake booster pushrod clevis.

Installation Notice

Apply the grease around the hold of clevis pin.

Remove the brake pedal-to-dash panel bracket nut and the bolt.
Remove the brake pedal from the dash panel bracket.
Remove the spring from the brake pedal.

Installation Notice

Tightening Torque

18 N•m (13 lb-ft)

Apply the grease around the hold of brake pedal shaft.

Remove the brake pedal cover.

SPECIFICATIONS

GENERAL SPECIFICATIONS

Application	Description
Capacity	0.5 Liter (0.53 qt)
Lubricant	DOT-3

Application	Millimeters	Inches
Front Disc Brake Rotor:
Diameter	256.00	10.08
Thickness(New)	24.00	0.95
Discard Thickness	22.00	0.87
Lateral Runout(Installed)	0.03	0.0012
Rear Drum Brake:
Inside Diameter	230.00	9.06
Maximum Rebore Diameter	231.00	9.09
Out-of-Round	0.1	0.0039
Booster:
Diameter	180 + 205	7 + 8
Servo Force Ratio	6 : 1	-
The Distance From The Booster To Fork Bin	162.4	6.39
Master Cylinder:
Bore Diameter	23.81	0.9374
Caliper:
Minimum Piston Diameter (Front)	57.0	2.2441
Wheel Cylinder:
Diameter	20.64	0.8126
Brake Pedal
Free Play	MAX. 10	MAX. 0.3937
Height	162 ± 10	6.3779 ± 0.3937
Stroke	MIN. 120	MIN. 4.7244

FASTENER TIGHTENING SPECIFICATIONS

Application	N•m	Lb-Ft	Lb-In
Brake Line Fitting Nut (Master Cylinder)	16	12	-
Bleeder Screw	9	6	80
Brake Hose-to-Caliper Bolt	40	30	-
Brake Pedal-to-Dash Panel Bracket Bolt and Nut	18	13	-
Brake Line Fitting Nut (Brake Hose)	16	12	-