3900631
Hexagon Flange Head Cap Screw
Cummins®

The Hexagon Flange Head Cap Screw, specifically part #3900631 manufactured by Cummins, plays a significant role in the assembly and maintenance of commercial trucks. This screw is designed to provide secure fastening in various truck components, ensuring the structural integrity and operational efficiency of the vehicle.

Basic Concepts

The Hexagon Flange Head Cap Screw is a type of fastener characterized by its hexagonal head and flanged base. The hexagonal head allows for efficient torque application using standard tools, while the flange provides additional surface area to distribute load and prevent the screw from sinking into the material. In the automotive industry, these screws are commonly used to fasten metal components, providing both strength and stability. The screw operates by threading into a pre-drilled hole, creating a secure connection that can withstand significant stress and vibration ¹.

Purpose and Function

This Cummins part is integral to the operation of a truck by securing various components together. It contributes to the assembly and integrity of truck parts by providing a robust fastening solution that can endure the harsh conditions encountered in commercial vehicle applications. This screw is often used in areas where vibration and dynamic loads are present, ensuring that critical components remain firmly attached ².

Key Features

The 3900631 Hexagon Flange Head Cap Screw boasts several key features that enhance its performance and durability. Its hexagonal head design allows for easy and precise torque application, reducing the risk of stripping or over-tightening. The flange characteristic provides additional bearing surface, which helps distribute the load more evenly and prevents the screw from pulling through the material. Additionally, the screw is made from high-quality materials that offer excellent resistance to corrosion and wear, ensuring long-lasting performance in demanding environments ³.

Benefits

The 3900631 Hexagon Flange Head Cap Screw offers several benefits that make it a preferred choice for commercial truck applications. One of the primary advantages is improved fastening security, which is crucial for maintaining the structural integrity of truck components. The design of the screw also provides resistance to vibration loosening, a common issue in vehicles subjected to rough road conditions. Furthermore, the ease of installation and removal makes it a convenient option for both initial assembly and maintenance procedures.

Troubleshooting and Maintenance

Common issues associated with Hexagon Flange Head Cap Screws include corrosion, stripping, and vibration loosening. To address these problems, regular inspection and maintenance are recommended. Ensuring that the screws are properly torqued during installation can prevent stripping and loosening. Additionally, applying a corrosion-resistant coating or using screws made from stainless steel can mitigate the risk of rust and degradation. If corrosion is detected, the affected screws should be replaced to maintain the integrity of the fastening.

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 spanning over a century, Cummins has established itself as a trusted name in the commercial vehicle industry. The company is committed to innovation and quality, consistently delivering products that meet the rigorous demands of commercial applications. Cummins’ expertise in engine and component design ensures that their fasteners, like the 3900631 Hexagon Flange Head Cap Screw, are reliable and perform well under various operating conditions.

Hexagon Flange Head Cap Screw 3900631 in Cummins Engines

The Hexagon Flange Head Cap Screw 3900631, manufactured by Cummins, is a crucial component in several of their engine models. This screw is integral to the assembly and maintenance of various engine parts, ensuring secure fastening and alignment.

Engine Models Utilizing 3900631

• 15N CM2380 M104B
• 4B3.9
• 6B5.9
• 6C8.3
• B3.9 G
• B4.5
• B4.5 CM2350 B129B
• B4.5 RGT
• B5.6 CM2670 B152B
• B5.9 CM2670 B166C
• B5.9 G
• B5.9 GAS PLUS CM556
• B6.7 CM2350 B135B
• B6.7 CM2670 B153B
• B6.7 CM2670 B164C
• B6.7 G CMOH6.0 B125
• B6.7S
• C GAS PLUS CM556
• C8.3 G
• D4.0 CM2620 D103B
• F2.8 CM2620 F135B
• F3.8 CM2350 F120B
• F3.8 CM2350 F128C
• F3.8 CM2620 F137B
• F3.8 F102

Grouping of Engine Models

The engines listed can be grouped based on their specifications and usage scenarios:

Group 1: Smaller Engines

• 4B3.9
• 6B5.9
• B3.9 G
• B4.5
• B4.5 CM2350 B129B
• B4.5 RGT
• F2.8 CM2620 F135B
• F3.8 F102

Group 2: Medium Engines

• 6C8.3
• B5.6 CM2670 B152B
• B5.9 CM2670 B166C
• B5.9 G
• B5.9 GAS PLUS CM556
• B6.7 CM2350 B135B
• B6.7 CM2670 B153B
• B6.7 CM2670 B164C
• B6.7 G CMOH6.0 B125
• B6.7S
• C GAS PLUS CM556
• C8.3 G
• F3.8 CM2350 F120B
• F3.8 CM2350 F128C
• F3.8 CM2620 F137B

Group 3: Larger Engines

• 15N CM2380 M104B
• D4.0 CM2620 D103B

Each group represents engines with similar power outputs and applications, making the Hexagon Flange Head Cap Screw 3900631 a versatile and essential part across Cummins’ engine lineup.

Role of Part 3900631 Hexagon Flange Head Cap Screw in Engine Systems

The 3900631 Hexagon Flange Head Cap Screw is integral to the assembly and securement of various components within engine systems. Its design allows for a robust connection, ensuring that parts remain firmly in place under the demanding conditions of engine operation.

Aftercooler Plumbing

In the aftercooler plumbing system, the 3900631 screw is used to secure fittings and connections, maintaining the integrity of the cooling process for compressed air. This ensures efficient temperature reduction before the air enters the engine.

Air Cleaner and Air Cleaner Brace

For the air cleaner and its brace, the screw plays a role in attaching the air cleaner to the engine block or other structural components. This securement is vital for maintaining the air cleaner’s position and function in filtering incoming air.

Alternator Support Kit

Within the alternator support kit, the screw is employed to fasten the alternator to the engine, providing the necessary stability for the alternator to generate electricity without vibration or movement that could lead to failure.

Auxiliary Cooling Plumbing

In auxiliary cooling systems, the screw is utilized to attach plumbing components, ensuring a leak-free and secure connection that aids in the dissipation of heat from engine components.

Camshaft Gear

The screw is also found in the attachment of the camshaft gear, where it secures the gear to the camshaft, ensuring precise timing and operation of the valve train.

Cylinder Block Cover

For the cylinder block cover, the screw is used to fasten the cover to the cylinder block, providing a seal that prevents coolant or oil leaks and protects internal components.

EBM-Plumbing

In EBM (Engine Block Mounted) plumbing, the screw secures various plumbing components to the engine block, ensuring a stable and leak-free system for fluid transfer.

Turbocharger

The turbocharger utilizes the screw to secure its components, such as the oil drain mounting, ensuring that the turbocharger operates efficiently and remains securely attached to the engine.

Engine Cooling System

Within the engine cooling system, the screw is used to fasten components such as the water pump arrangement and flexible hose connections, maintaining the system’s integrity and efficiency in dissipating heat.

Exhaust Recirculation

For exhaust recirculation systems, both air and water plumbing, the screw secures components that reroute exhaust gases back into the engine for reduced emissions, ensuring a tight and secure fit.

Flexible Hose

In applications involving flexible hoses, the screw is used to connect hoses to fittings, providing a secure and leak-free connection that can withstand the dynamic movements and pressures within the engine system.

Flywheel

The screw is also instrumental in securing the flywheel to the crankshaft, ensuring that the flywheel operates smoothly and efficiently in storing and releasing rotational energy.

Fuel Pump and Drive

In the fuel pump and drive system, the screw is used to attach the fuel pump to the engine, ensuring a stable supply of fuel under pressure to the engine’s combustion chambers.

Fuel Supply Plumbing

For fuel supply plumbing, the screw secures connections and fittings, ensuring a leak-free and stable fuel delivery system to the engine.

Hydraulic Drive Housing

Within the hydraulic drive housing, the screw is used to fasten components, ensuring the housing remains intact and functions correctly in transmitting hydraulic power.

Kit, Fuel Pump Conv and Kit, Fuel Pump Conv.

In conversion kits for fuel pumps, the screw is utilized to secure new components, ensuring a smooth transition and operation of the fuel system with the upgraded pump.

Kit, On Board Spares

For on-board spares kits, the screw is used to secure spare parts within their storage compartments, ensuring they are readily available for maintenance or repair without risk of loss or damage.

Long Block

In the assembly of a long block, the screw is employed to fasten various components, ensuring the engine’s structural integrity and operational efficiency.

Oil Pan Service Kit

The screw is used in oil pan service kits to secure the oil pan to the engine block, ensuring a sealed environment for the engine’s lubrication system.

Throttle Valve

For the throttle valve, the screw secures the valve to its housing, ensuring precise control over the airflow into the engine for optimal performance.

Water Pump Arrangement

In the water pump arrangement, the screw is used to fasten the water pump to the engine, ensuring efficient circulation of coolant throughout the engine for temperature regulation.

Conclusion

The 3900631 Hexagon Flange Head Cap Screw is a critical component in the assembly and maintenance of Cummins engines. Its robust design, resistance to corrosion and vibration, and ease of use make it an indispensable part in ensuring the structural integrity and operational efficiency of commercial trucks. Regular maintenance and proper installation are essential to maximize the benefits of this screw and ensure the longevity of the engine components it secures.