Which of the following incorrect service procedures can lead to brake lock-up?

The adjustment of the master cylinder push rod is crucial for the proper function of the braking system. When the push rod is adjusted too long, it can prevent the brake piston from fully returning to its resting position. This can cause the brake pads to remain in contact with the rotors, leading to increased friction, overheating, and ultimately brake lock-up.

This scenario can create a situation where the brakes continuously apply pressure, even when the driver is not engaging the brake pedal. Therefore, a long push rod will not allow the brake system to achieve the necessary clearance, resulting in unintended brake application and potential lock-up during operation. It highlights the importance of precise adjustment to avoid malfunctions and ensure safe vehicle operation.