Service Manual2004 POWER BOOSTER

SECTION 4C

POWER BOOSTER

DESCRIPTION AND OPERATION

GENERAL DESCRIPTION

The power booster is a single-diaphragm, vacuum-suspended unit. In normal operating mode, with the service brakes in the release position, a vacuum-suspended booster operates with a vacuum on both sides of its diaphragm. When the brakes are applied, air at atmospheric pressure is admitted to one side of the diaphragm to provide the power assist. When the brakes are released, atmospheric air is shut off from that side of the diaphragm.

The air is then drawn from the booster through the vacuum check valve by the vacuum source.

Important : If any hydraulic component is removed or disconnected, it may be necessary to bleed all or part of the brake system. Refer to Section 4F, Antilock Brake System and Traction Control System.

DIAGNOSTIC INFORMATION AND PROCEDURES

POWER BOOSTER FUNCTIONAL CHECK

With the engine stopped, eliminate vacuum in the booster by pumping the brake pedal several times.
Push the pedal down and hold in this position.
Start the engine.
The booster is OK if the pedal drops further because of extra force produced.

If the brake pedal does not drop, the vacuum system (vacuum hoses, check valve, etc.) is probably defective and should be checked.

If no defect is revealed by checking the vacuum system, the defect is in the booster itself.

CHECK VALVE FUNCTIONAL CHECK

Remove the vacuum hose.
Suck the vacuum hose to power booster. And also, suck the vacuum hose to engine.
If the air pass through the check valve or not, replace the check valve. And if the vacuum hose to engine is only sucked, the check valve OK.

REPAIR INSTRUCTIONS

ON-VEHICLE SERVICE

VACUUM HOSE

(Left-Hand Drive Shown, Right-Hand Drive Similar)

Removal and Installation Procedure

Remove the air intake tube from the air filter housing. (Right-Hand Drive Only)
Remove the clips on the vacuum hose connection to the intake manifold and the brake booster.
Remove the vacuum hose.

Installation Notice

Check the function of the booster. Refer to the "Power Booster Function Check" in this section.

POWER BOOSTER ASSEMBLY

(Left-Hand Drive Shown, Right-Hand Drive Similar)

Removal and Installation Procedure

Remove the engine. Refer to Section 1C, DOHC Engine Mechanical.(Right-Hand Drive Only).
Remove the master cylinder. Refer to Section 4B, Master Cylinder.
Remove the vacuum hose from the brake booster. Refer to the "Vacuum Hose" in this section.

Remove the clevis pin and disconnect the pedal and brake booster push rod.
Disconnect the retaining clip and the pin from the brake booster pushrod clevis.
Remove the brake booster mounting nuts from studs protruding from dash panel and remove the brake booster.

Installation Notice

Tightening Torque

25 N•m (18 lb-ft)

Apply the grease around the hole of pushrod clevis pin.

Remove and discard the gasket.

Remove the pushrod clevis.

Remove the hex nut from the pushrod.

Installation Notice

Tightening Torque

18 N•m (13 lb-ft)

Install the new gasket.

Remove the spring clip.

Remove the rubber boot.

Measure the distance from the booster to the center of the fork bin bore. This measurement should be 162.4 mm(6.39 inches).
Right-Hand Drive: 127.4mm(5.02 inches)
Check the function of the booster. Refer to the "Power Booster Function Check" in this section.
After the installation, bleed the brake system. Refer to Section 4A, Hydraulic Brakes.
Check the brake system for leaks.
Care must be taken to prevent the brake fluid from contacting any painted surface to prevent damage to the paint finish.

SPECIFICATIONS

GENERAL SPECIFICATIONS

Application		Unit	Description
Power Booster	Type	-	Vacuum-Suspended
	Diameter	mm (inch)	180 (7) + 205 (8)
	Servo Force Ratio	-	5 : 1
	The Distance From The Booster To Fork Bin	mm (inch)	LHD: 162.4 (6.39) RHD: 127.4 (5.02)

FASTENER TIGHTENING SPECIFICATIONS

Application	N•m	Lb-Ft	Lb-In
Dash Panel-to-Brake Booster Mounting Nut	25	18	-
Pushrod Clevis Nut	18	13	-