Mack Screw Cap 25091811, 1AX509

This is a hexagon screw (often referred to as a bolt or screw cap) used in heavy-duty truck applications.

Technical Overview

Average Weight: ~ 0.35 kg

Supersession: 1AX509 > 25091811

Specifications: 5/8-18 x 8-1/2 Grade 5 bolt.

Primary Application: It is widely used in heavy-duty suspension systems, specifically associated with torque rods and rod bushings on Mack truck chassis.

SL: 1C

Key Information

This is a high-tensile fastener designed for critical structural applications. It is frequently associated with components like torque rods, suspension linkages, and other chassis mounting points where high vibration and mechanical stress occur.

Being a genuine Mack replacement part, it is engineered to meet specific hardness, tensile strength, and corrosion-resistance requirements. In heavy-duty trucking, fasteners are not interchangeable with standard hardware-grade bolts; using the wrong grade can lead to fastener failure, which is especially dangerous in suspension or engine mounting scenarios.