3903990
Hexagon Flange Head Cap Screw
Cummins®

Introduction

The Hexagon Flange Head Cap Screw, specifically the 3903990 model by Cummins, is essential for the assembly and maintenance of commercial trucks. This screw provides secure fastening in heavy-duty applications, ensuring the integrity and durability of truck components. Its unique design and robust construction make it a vital component in various truck assemblies.

Basic Concepts and Functionality

The Hexagon Flange Head Cap Screw is characterized by its hexagonal socket and flanged head. The hexagonal socket allows for efficient torque application using a socket wrench, while the flange head provides a larger bearing surface that distributes the load more evenly, reducing the risk of damage to the fastened material ¹. Typically made from high-strength materials such as alloy steel, these screws are designed to withstand significant stress and vibration. The mechanical principles at play involve the screw’s thread engaging with the material, creating friction that holds components together securely ².

Role in Truck Operation

In truck operation, the 3903990 Hexagon Flange Head Cap Screw is utilized in various components and assemblies. It is commonly found in engine mounts, transmission housings, and chassis components where secure and durable fastening is required. The screw contributes to the overall functionality and durability of the vehicle by ensuring that critical components remain firmly in place, even under heavy-duty conditions.

Key Features

The 3903990 Hexagon Flange Head Cap Screw boasts several key features that enhance its performance and reliability. Its flange design provides a larger contact area, which helps in distributing the load and preventing the screw from pulling through the material. The material properties, often including alloy steel with a high tensile strength, ensure that the screw can withstand significant stress. The thread type is typically a coarse or fine thread, depending on the application, which affects the screw’s holding power and ease of installation. Additionally, special coatings or treatments may be applied to improve corrosion resistance and longevity.

Benefits

The benefits of using the 3903990 Hexagon Flange Head Cap Screw include improved fastening security, resistance to vibration loosening, ease of installation and removal, and durability under heavy-duty conditions. The design of the screw allows for secure fastening that can withstand the dynamic loads and vibrations encountered in truck operations. Its ease of installation and removal makes it a practical choice for maintenance and repair tasks. Furthermore, the durability of the screw ensures long-term performance, reducing the need for frequent replacements.

Troubleshooting and Maintenance

Common issues associated with Hexagon Flange Head Cap Screws include corrosion, stripping, or loosening. To address these issues, regular inspections should be conducted to identify any signs of wear or damage. If corrosion is detected, cleaning and reapplying a protective coating may be necessary. In cases of stripping, replacing the screw is typically the best course of action. To prevent loosening, ensuring proper torque settings during installation is crucial. Regular maintenance, including inspections and torque checks, will help ensure the longevity and performance of the screw.

About Cummins

Cummins Inc. is a global power leader that designs, manufactures, and distributes diesel and natural gas engines, as well as related technologies. With a history of innovation and a commitment to quality, Cummins has established itself as a trusted provider of critical components for the commercial vehicle industry. The company’s expertise in engine technology and component manufacturing is reflected in products like the 3903990 Hexagon Flange Head Cap Screw, which is designed to meet the demanding requirements of heavy-duty truck applications.

Cummins Engine Compatibility with Hexagon Flange Head Cap Screw Part 3903990

The Cummins part 3903990, a Hexagon Flange Head Cap Screw, is designed to fit a variety of Cummins engines. This screw is integral in securing various components within the engine assembly, ensuring structural integrity and proper function. Below is a detailed look at the compatibility of this screw with different Cummins engine models.

15N CM2380 M104B

The 15N CM2380 M104B engine benefits from the 3903990 screw in securing critical components, ensuring the engine’s operational efficiency and longevity.

4B3.9, 6B5.9, 6C8.3

These engines, including the 4B3.9, 6B5.9, and 6C8.3, utilize the 3903990 screw for fastening parts that require a robust and reliable connection, maintaining the structural integrity of the engine.

B4.5 Series

The B4.5, B4.5 CM2350 B129B, and B4.5 RGT engines all incorporate the 3903990 screw in their assembly. This screw is essential for securing various engine components, ensuring they remain tightly fastened and in place.

B5.6, B5.9 Series

Engines such as B5.6 CM2670 B152B, B5.9 CM2670 B166C, B5.9 G, and B5.9 GAS PLUS CM556 use the 3903990 screw to secure critical parts, ensuring the engine’s components are held firmly together.

B6.7 Series

The B6.7 CM2350 B135B, B6.7 CM2670 B153B, B6.7 CM2670 B164C, B6.7 G CMOH6.0 B125, B6.7S, and C GAS PLUS CM556 engines all feature the 3903990 screw in their design. This screw is vital for maintaining the structural integrity of these engines by securing various components.

D4.0 CM2620 D103B

The D4.0 CM2620 D103B engine utilizes the 3903990 screw to ensure that critical components are securely fastened, contributing to the engine’s overall performance and durability.

F2.8, F3.8 Series

Engines such as F2.8 CM2620 F135B, F3.8 CM2350 F120B, F3.8 CM2350 F128C, F3.8 CM2620 F137B, F3.8 F102, and F4.5 CM2620 F139B all incorporate the 3903990 screw. This screw is essential for securing various parts within these engines, ensuring they remain tightly fastened and in place.

Each of these engines relies on the 3903990 screw to maintain the structural integrity and operational efficiency of their components. This screw is a critical part of the engine assembly, ensuring that all parts are securely fastened and functioning as intended.

Understanding the Role of Part 3903990 Hexagon Flange Head Cap Screw in Engine Systems

The part 3903990 Hexagon Flange Head Cap Screw is a versatile component utilized in various engine systems to ensure secure and reliable connections. Its application spans across multiple components, contributing to the overall efficiency and performance of the engine.

Accessory Drive Pulley and Accessory Support

In the accessory drive system, the Hexagon Flange Head Cap Screw is employed to fasten the accessory drive pulley to the accessory support. This secure attachment ensures that the pulley operates smoothly, driving essential accessories like the alternator and water pump. The screw’s flange head provides additional surface area, enhancing the stability and reducing the risk of loosening under operational stress.

Vibration Damper and Belt System

The vibration damper is critical for reducing engine vibrations, and the Hexagon Flange Head Cap Screw plays a role in mounting this component to the engine block. Additionally, in belt-driven systems, these screws are used to secure the belt tensioner, ensuring optimal belt tension for efficient power transmission to accessories like the compressor and refrigerant system.

Compressor and Refrigerant System

Within the refrigerant system, the Hexagon Flange Head Cap Screw is utilized to secure the compressor to its mounting points. This ensures that the compressor remains firmly in place, allowing for consistent and reliable operation. The screw’s design helps in withstanding the dynamic forces generated during compression cycles.

Connection and Water Inlet

For components like the water inlet and cover, the Hexagon Flange Head Cap Screw provides a robust connection to the engine block. This is vital for maintaining the integrity of the cooling system, ensuring that coolant flows efficiently through the system without leaks.

Cam Follower and Doser

In systems involving cam followers and dosers, such as those found in fuel injection systems, the Hexagon Flange Head Cap Screw is used to secure these components. This ensures precise operation and timing, which are essential for optimal engine performance and emissions control.

Fluid Drive and Fan

The fluid drive system, including the fan and heat exchanger, relies on the Hexagon Flange Head Cap Screw to maintain secure connections. This is particularly important in ensuring that the fan operates efficiently to dissipate heat, contributing to the overall thermal management of the engine.

Expansion Tank Mounting and Fuel Pump

For the expansion tank mounting and fuel pump, the Hexagon Flange Head Cap Screw provides a stable attachment to the engine or frame. This is essential for maintaining the structural integrity of these components, ensuring they function correctly under varying operational conditions.

Lubricating Oil Pump and Mounting Adapter

In the lubricating oil pump system, these screws are used to secure the pump to its mounting adapter. This ensures that the pump operates within specified tolerances, providing consistent lubrication to engine components.

Nitrogen Oxide Sensor and Thermostat Housing

The nitrogen oxide sensor and thermostat housing are critical for monitoring and regulating engine performance. The Hexagon Flange Head Cap Screw is used to secure these components, ensuring they remain in place and function accurately.

Regulator and Fuel Pressure Support

For the fuel pressure regulator and support systems, the Hexagon Flange Head Cap Screw plays a role in maintaining secure connections. This is essential for ensuring consistent fuel pressure, which is critical for engine efficiency and performance.

Alternator and Ignition System

Finally, in the alternator and ignition system, these screws are used to secure various components, ensuring they operate reliably. This contributes to the overall electrical system’s stability, which is vital for engine starting and operation.

The Hexagon Flange Head Cap Screw’s role in these engine systems underscores its importance in maintaining secure, reliable connections across a wide range of components.

Conclusion

The 3903990 Hexagon Flange Head Cap Screw by Cummins is a critical component in the assembly and maintenance of commercial trucks and various engine systems. Its robust design, key features, and benefits make it an indispensable part in ensuring the secure fastening of critical components, contributing to the overall durability and performance of the vehicle. Regular maintenance and proper installation are essential to maximize the screw’s longevity and effectiveness.