The expansion bolt K 34129 is a specialized fastening component designed to secure the piston skirt within the operating piston assembly of the Sulzer ZV40/48 engine. Its primary function is to provide a strong, vibration-resistant mechanical connection capable of maintaining secure clamping forces despite thermal expansion and cyclic operating loads. Manufactured from high-strength alloy steel with excellent fatigue and corrosion resistance, the expansion bolt is engineered to perform reliably under demanding marine and industrial operating conditions. Precision machining ensures accurate preload, uniform load distribution, and dependable long-term fastening performance. By preventing loosening and preserving structural integrity, the K 34129 expansion bolt contributes to reliable piston operation, improved mechanical stability, reduced maintenance requirements, and extended service life of the operating piston assembly.