Rotary joints are essential components, in many industrial applications, to transfer fluids under pressure between a fixed and a rotating part. However, like any mechanical component, they can be vulnerable to failure or malfunction. Identifying and understanding the main causes of these problems is crucial to extend their service life, improve performance, and reduce maintenance costs. Here, we explore the most common causes of failures in rotary joints and how to prevent them.     1.    Incorrect Installation   Improper installation is one of the most common causes of malfunction in rotary joints. Common faults include:   1- Improper alignment: Poor alignment between the joint and the cylinder or spindle can generate mechanical stresses and accelerate wear of internal parts.