Nissan Versa

 Sedan Service Manual

Brakes » Brake system (BR) » Brake booster and check valve
Inspection and Adjustment

INSPECTION BEFORE REMOVAL

Brake System Vacuum Inspection

CAUTION: Check the vacuum condition when the master cylinder and the brake booster are installed.

1. Check the vacuum using a suitable tool.

At vacuum of −66.7 kPa (−500 mmHg, −19.69 inHg) : Vacuum should decrease within 3.3 kPa (24.8 mmHg, 0.98 inHg) for 15 seconds.

    2.   If the vacuum cannot be maintained, perform the following operation.

a. Check that dirt and dust are not present on the brake booster and brake master cylinder mating surfaces.

Clean the mating surfaces if necessary.

b. Check the O-ring on the master cylinder. If anything is found, replace the O-ring. Refer to BR "Removal and Installation".

c. Check the vacuum condition again. If the condition still cannot be maintained, replace the brake booster.

INSPECTION AFTER REMOVAL

Check Valve Vacuum Inspection

1. Check the vacuum using a suitable tool.

When connected to the booster side : Vacuum should decrease within 1.3 kPa (9.8 mmHg, 0.38 inHg) for 15 seconds under a vacuum of −66.7 kPa (−500 mmHg, − 19.69 inHg).

When connected to the vacuum hose side :Vacuum should not exist.

    2.   If the vacuum still cannot be maintained, replace the check valve.

Input Rod Length Inspection

1. Loosen the lock nut (1) and adjust the input rod (2) to the specified length (A).

(A) : Refer to BR "Brake Booster".

    2.   Tighten the lock nut to the specified torque.

INSPECTION AFTER INSTALLATION

Operation

Depress the brake pedal several times at 5-second intervals with the engine stopped. Start the engine with the brake pedal fully depressed. Check that the clearance between brake pedal and dash lower pane decreases.

NOTE: A slight impact with a small click may be felt on the pedal when the brake pedal is fully depressed. This is a normal phenomenon due to the brake system operation.

Air Tight

1. Run the engine at idle for 1 minute to apply vacuum to the brake booster, and stop the engine. Then depress the brake pedal several times at 5-second intervals until the accumulated vacuum is released to atmospheric pressure. Check that the clearance between brake pedal and dash lower panel gradually increases each time the brake pedal is depressed when performing this operation.
2. Depress the brake pedal with the engine running. Then stop the engine while holding down the brake pedal. Check that the brake pedal stroke does not change after holding down the brake pedal for 30 seconds or more.

ADJUSTMENT AFTER INSTALLATION

Perform the brake pedal adjustment after installing the brake pedal assembly. Refer to BR"Inspection and Adjustment".

Removal and installation

Inspection and Adjustment