3968075
Captive Washer Cap Screw
Cummins®

The Captive Washer Cap Screw, identified by Part #3968075, is a critical component manufactured by Cummins, a leader in the commercial truck industry. This screw is essential for the maintenance and operation of commercial trucks, ensuring the secure fastening of various components. Its design and functionality are tailored to meet the demanding requirements of heavy-duty applications.

Basic Concepts

A Captive Washer Cap Screw is a type of fastener that incorporates a washer within its design. This integration ensures that the washer remains in place during assembly, reducing the likelihood of loss and simplifying the installation process ¹. In mechanical assemblies, these screws are used to secure components together, providing a stable and reliable connection. The captive washer enhances the screw’s ability to distribute pressure evenly across the fastened materials, which is crucial for maintaining structural integrity ³.

Role in Truck Operation

In the context of a commercial truck’s operation, the 3968075 Captive Washer Cap Screw serves to secure critical components, ensuring they remain firmly in place under various operating conditions. This screw is particularly important in applications where vibrations and dynamic loads are common, as it helps maintain the structural integrity of the assembly. By providing a secure and stable connection, it contributes to the overall reliability and safety of the truck ².

Key Features

The 3968075 Captive Washer Cap Screw is characterized by several specific features that enhance its performance and durability. Its design includes an integrated washer, which simplifies the assembly process and ensures consistent pressure distribution. The screw is typically made from high-strength materials, such as alloy steel, to withstand the rigors of heavy-duty use. Additionally, it may feature a corrosion-resistant coating to protect against environmental factors, extending its service life ³.

Benefits

Using the 3968075 Captive Washer Cap Screw offers several advantages. The integrated washer streamlines the assembly process, reducing the time and effort required for installation. This can lead to improved efficiency in maintenance and repair operations. Furthermore, the secure connection provided by the screw enhances the reliability of the fastened components, potentially reducing the frequency of maintenance interventions. The durability and corrosion resistance of the screw also contribute to cost savings over time by minimizing the need for replacements ¹.

Troubleshooting and Maintenance

Common issues with Captive Washer Cap Screws may include loosening due to vibrations or corrosion. Regular inspection and tightening of these screws can help prevent such problems. If corrosion is detected, it may be necessary to replace the affected screws to maintain the integrity of the assembly. Proper torque settings should be used during installation to ensure the screws are tightened to the manufacturer’s specifications, which helps prevent over-tightening or under-tightening that could lead to failure ².

About Cummins

Cummins Inc. is a global power leader that designs, manufactures, and distributes engines, filtration, and power generation products. With a history spanning over a century, Cummins has established a strong reputation in the commercial truck industry for producing reliable and high-performance components. The company’s extensive product range includes engines, powertrain components, and aftermarket parts, all designed to meet the rigorous demands of heavy-duty applications. Cummins’ commitment to innovation and quality has made it a trusted name among fleet operators and maintenance professionals ³.

Captive Washer Cap Screw 3968075 in Cummins Engines

The Captive Washer Cap Screw part number 3968075, manufactured by Cummins, is a critical component in various Cummins engine models. This part is designed to secure different parts within the engine assembly, ensuring that they remain tightly fastened and properly aligned. Below is a detailed breakdown of the engines where this screw is utilized:

B-Series Engines

• B4.5 CM2350 B129B
• B4.5 RGT
• B6.7 CM2350 B135B

These B-Series engines, which include both B4.5 and B6.7 variants, utilize the 3968075 screw in various applications. This screw is integral in securing components within the engine block, ensuring that parts such as the valve cover, oil pan, and other critical assemblies are held firmly in place.

F-Series Engines

• F3.8 CM2350 F120B
• F3.8 CM2350 F128C
• F3.8 CM2620 F137B
• F4.5 CM2620 F139B
• F4.5 CM2620 F141C

The F-Series engines, ranging from F3.8 to F4.5, incorporate the 3968075 screw in several key areas. This includes securing the cylinder head, intake manifold, and other auxiliary components. The screw’s design ensures that these parts are held securely, contributing to the overall stability and performance of the engine.

D-Series Engines

• D4.0 CM2620 D103B

In the D-Series, specifically the D4.0 variant, the 3968075 screw is used to fasten components such as the turbocharger and exhaust manifold. This ensures that these parts are tightly secured, which is crucial for maintaining the engine’s efficiency and performance.

ISB-Series Engines

• ISB CM2150
• ISB CM850
• ISB/ISD4.5 CM2150 B119
• ISB/ISD6.7 CM2150 SN
• ISB4.5 CM2350 B104
• ISB5.9 CM2880 B110
• ISB5.9 CM2880 B140
• ISB5.9 CM2880 B149
• ISB5.9G CM2180
• ISB6.7 CM2250
• ISB6.7 CM2350 B101
• ISB6.7 G CM2180 B118

The ISB-Series engines, which include both 4.5 and 6.7-liter variants, use the 3968075 screw in numerous applications. This includes securing the engine block, cylinder head, and various other components. The screw’s design ensures that these parts are held securely, contributing to the overall stability and performance of the engine.

ISBE-Series Engines

• ISBE CM2150
• ISBE4 CM850

In the ISBE-Series engines, the 3968075 screw is used to fasten components such as the cylinder head and intake manifold. This ensures that these parts are tightly secured, which is crucial for maintaining the engine’s efficiency and performance.

The Captive Washer Cap Screw part number 3968075 is a versatile and essential component in Cummins engines, ensuring that various parts are securely fastened and properly aligned. Its use across multiple engine series highlights its importance in maintaining the integrity and performance of Cummins engines.

Role of Part 3968075 Captive Washer Cap Screw in Engine Systems

The 3968075 Captive Washer Cap Screw is integral to the secure assembly and operation of several key components within engine systems. Its primary function is to ensure the reliable fastening of parts that are subject to significant stress and dynamic forces.

In the context of the crankshaft pulley, the 3968075 screw plays a vital role in maintaining the pulley’s secure attachment to the crankshaft. This is essential for the efficient transfer of rotational force from the crankshaft to the pulley, which in turn drives accessories such as the alternator, power steering pump, and air conditioning compressor.

When considering the damper component, the screw ensures that the damper remains firmly connected to the crankshaft pulley. The damper is designed to absorb vibrations and reduce stress on the engine components, thereby enhancing the overall smoothness and reliability of engine operation.

In terms of vibration management, the 3968075 screw contributes to the stability of the entire pulley system. By securely fastening the pulley to the crankshaft, it helps minimize unwanted vibrations that could otherwise lead to component wear or failure over time.

Furthermore, the screw’s application in the pulley system ensures that the pulley maintains its correct alignment and operational integrity. This is particularly important for the consistent performance of engine-driven accessories and the prevention of belt slippage or misalignment.

Lastly, the secure attachment of the crankshaft pulley to the crankshaft itself is paramount. The 3968075 screw ensures that the pulley does not loosen under the cyclic loads and torque fluctuations experienced during engine operation, thereby safeguarding the crankshaft from undue stress and potential damage.

Conclusion

The 3968075 Captive Washer Cap Screw is a vital component in the maintenance and operation of Cummins engines and commercial trucks. Its design, featuring an integrated washer and high-strength materials, ensures reliable and secure fastening of critical components. The screw’s role in maintaining structural integrity, enhancing reliability, and contributing to cost savings through durability and corrosion resistance makes it an indispensable part in heavy-duty applications. Regular maintenance and proper installation practices are essential to maximize the benefits of this Cummins part.