Hyundai Tucson: Brake Booster Operating

Components

1. Reservoir cap
2. Reservoir
3. Brake booster
4. Master cylinder
5. Push rod

Test

1. Run the engine for one or two minutes, and then stop it. If the pedal depresses fully the first time but gradually becomes higher when depressed succeeding times, the booster is operating properly, if the pedal height remains unchanged, the booster is inoperative.

2. With the engine stopped, step on the brake pedal several times.

   Then step on the brake pedal and start the engine. If the pedal moves downward slightly, the booster is in good condition. If there is no change, the booster is inoperative.

3. With the engine running, step on the brake pedal and then stop the engine.Hold the pedal depressed for 30 seconds. If the pedal height does not change, the booster is in good condition, if the pedal rises, the booster is inoperative.

If the above three tests are okay, the booster performance can be determined as good.

Even if one of the above three tests is not okay, check the check valve, vacuum hose and booster for malfunction.

Removal

1. Turn ignition switch OFF and disconnect the negative (-) battery cable.
2.  Remove the battery and battery tray.

   (Refer to Engine Electrical System - "Battery")

3. Remove the air duct and air cleaner assembly.

   (Refer to Intake and Exhaust System - "Air Cleaner")

4. Remove the master cylinder.

   (Refer to Brake System - "Master Cylinder")

5. Remove the fixing clip and the vacuum hose (A) from the brake booster.

6. Disconnect the brake booster vacuum pressure sensor connector (A).

1. Remove the snap pin (B) and the clevis pin (A).

8. Remove the brake booster (B) after loosening the mounting nuts (A).

Tightening torque : 16.7 - 25.5 N.m (1.7 - 2.6 kgf.m, 12.3 - 18.8 lb-ft)

Inspection

1. Inspect the vacuum hose.
2. Check the boot for damage.

Installation

1. Installation is the reverse of removal.

WARNING

• Before installing the pin. apply the grease to the joint pin.
• Use a new snap pin whenever installing.

2. After installation, bleed the brake system.

   (Refer to Brake System - "Brake Bleeding Procedures")

3. Check the brake oil leakage and pedal operating condition.

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