Brake system maintenance (Hyundai Tucson LM)

Checking the brake booster

To simply check the operation of the vacuum booster, you need to do the following.

1. Start the engine, let it run for 1-2 minutes, and stop it. Press the brake pedal several times with normal force. If the pedal goes down the first time you press it, but gradually rises the second or third time you press it, the brake booster is working properly. If the pedal height does not change, the booster is faulty.



2. With the engine off, press the brake pedal several times and check the change in pedal height. Then press the pedal and start the engine. If the pedal moves down a little, the booster is working properly. If the pedal height remains the same, the booster is faulty.



3. With the engine running, press the brake pedal and stop the engine. Keep the pedal depressed for 30 seconds. If the pedal height does not change during this time, the booster is OK. If the pedal rises, the booster is faulty.



The original text is available on the website (HyundaiBook)

If any of the above checks reveal a fault, check the check valve, vacuum hose and booster and correct the faults. If the checks are positive, the booster is in good condition.

Pumping the system

Attention.

• Do not reuse brake fluid.
• Always use only the recommended DOT 3 or DOT 4 brake fluid. Using non-original brake fluid can lead to corrosion and significantly reduce the service life of the brake system.
• Make sure the brake fluid is free of impurities and contaminants.
• Do not allow brake fluid to come into contact with the body surfaces, as this may damage the paintwork. If brake fluid does come into contact with the body, wash it off immediately with water.
• The brake fluid level in the expansion tank should always be at the MAX mark. It is necessary to check the level regularly and add brake fluid to the system if necessary.

1. Make sure that the brake fluid level in the expansion tank is at the "MAX" mark.

2. Attach a vinyl hose to the bleed nipple on the wheel cylinder, lower the other end of the hose into a container of brake fluid.



3. Press the brake pedal several times.

4. With the pedal fully depressed, loosen the bleed screw (A) until brake fluid begins to flow out, then tighten the screw.





5. Repeat steps 3 and 4 until there are no air bubbles in the flowing liquid.

6. Tighten the air bleed screw.

7. Perform the specified operations on the remaining wheels in the order shown in the figure.



8. Fill the expansion tank of the master brake cylinder to the "MAX" mark.