The rear leak bag for the Citroën GSA, GS, and BX is a specially designed rubber or plastic component in the hydraulic suspension system of Citroën vehicles. These leak bags ensure that hydraulic fluid can circulate effectively and maintain pressure for smooth and comfortable suspension operation. Over time, they may develop leaks due to wear and tear, leading to suspension malfunctions. It is essential to periodically check and replace them if necessary to maintain the car's performance and driving experience. Replacement ensures optimal safety and driving comfort.