S155
Hexagon Head Cap Screw
Cummins®

The S155 Hexagon Head Cap Screw, manufactured by Cummins, is a specialized fastener designed for use in commercial trucks and various Cummins engines. This part plays a significant role in the assembly and maintenance of engine components, ensuring structural integrity and operational efficiency.

Basic Concepts of Hexagon Head Cap Screws

A Hexagon Head Cap Screw is characterized by its hexagonal head, which allows for efficient tool engagement. This design ensures secure fastening, minimizing the risk of cam-out and providing precise torque application. The hexagonal shape is advantageous in applications requiring strong, reliable fastening solutions ¹.

Role of S155 Hexagon Head Cap Screw in Truck and Engine Operation

In commercial trucks and Cummins engines, the S155 screw is utilized in the assembly of truck frames, body panels, and various mechanical components. It provides a strong, reliable fastening solution that can withstand the rigors of heavy-duty operation. The screw’s design ensures it remains securely in place under significant stress and vibration ².

Key Features

The S155 Hexagon Head Cap Screw is distinguished by several key features:

• Made from high-strength materials like alloy steel, providing necessary tensile strength for heavy-duty applications.
• Features a coarse thread for quick and easy installation, offering a strong grip.
• May be treated with a special coating to improve corrosion resistance, ensuring longevity in various operating conditions ³.

Benefits

Using the S155 Hexagon Head Cap Screw offers several advantages:

• Improved fastening security, reducing the likelihood of loosening over time.
• Resistance to vibration, beneficial in the dynamic environment of a commercial truck.
• Durability to withstand harsh operating conditions, providing long-term reliability.

Troubleshooting and Maintenance

To maintain the performance and longevity of the S155 screw, it is important to:

• Conduct regular inspections to identify screws at risk of loosening, allowing for timely re-tightening.
• Clean and apply protective coatings in cases of corrosion to prevent further degradation.
• Ensure correct torque specifications are used during installation to contribute to the screw’s reliability.

Cummins Engines Utilizing S155 Screw

The S155 screw is used in various Cummins engines, including:

• 4B3.9, 6B5.9, 6C8.3, C8.3 G, K19, K38, K50, QSC8.3 CM554, QSB5.9 CM850, QSK19 CM2350 K114
• C GAS PLUS CM556, ISC CM554, ISC CM850, ISL CM554, ISL9 CM2150 SN, KTA19GC, KTA19GC CM558, KTA38GC CM558
• N14 CELECT, N14 CELECT PLUS, N14 G, N14 MECHANICAL, NH/NT 855, GTA38 G CMEICS G116C, G855

In these engines, the S155 screw is integral to securing engine blocks, cylinder heads, turbochargers, and other auxiliary systems, ensuring precise alignment and stability for efficient operation.

Common Applications

Across all these engines, the S155 screw is consistently used in areas requiring high strength and precision. Its design allows for easy installation and removal, facilitating maintenance and repair processes. The use of this screw in Cummins engines underscores the company’s commitment to quality and durability in its engine components.

Role of S155 Hexagon Head Cap Screw in Engine Systems

The S155 screw is integral to the assembly and functionality of various engine components, including:

• Cylinder Air Compressor: Secures the compressor housing to the engine block.
• Accessories and Air Starting: Mounts various components to the engine.
• Air Cleaner Mounting and Strap: Ensures a tight and secure fit for the air filtration system.
• Base Parts and Expansion Tank: Fastens these components to the engine framework.
• Fuel Inlet Assembly and Generator: Secures components for efficient fuel delivery and generator operation.
• Heat Exchanger and Connections: Ensures tight fastening for efficient heat transfer.
• Hydraulic Mounting Pump and Idler Assembly Fan: Secures these components for smooth operation.
• Oil Pan and Mounting Adapter: Maintains the structural integrity of the oil pan.
• Oil Cooler Brace and Plumbing: Ensures secure fluid pathways for engine lubrication and cooling.
• Power Take-Off Housing and Remote Mounting Governor: Secures these components for correct operation.
• Fuel Water Separator and Turbocharger Conversion Kit: Maintains efficiency of fuel delivery and turbocharger operation.
• Water Manifold: Ensures secure connections for the engine’s cooling system.

Conclusion

The S155 Hexagon Head Cap Screw is a vital component in the assembly and maintenance of Cummins engines and commercial trucks. Its design and features ensure secure fastening, resistance to vibration, and durability under harsh operating conditions. Regular maintenance and correct installation practices are essential to maximize its performance and longevity.