5/16-18 x 3/4 Hex Bolt by Trans-Dapt Black Alloy Steel

Description

Product Overview

The Trans‑Dapt 5/16‑18 × 3/4 hex bolt is engineered for high‑performance automotive exhaust systems. Constructed from black‑coated alloy steel, the bolt meets Grade 5 hardness standards and delivers a maximum shear strength of 60 ksi (413.7 MPa). Its hex head design provides a secure, torque‑resistant fit, while the standard right‑hand thread ensures compatibility with a wide range of exhaust headers and manifolds. Each bolt measures 0.31 inches in diameter and 0.75 inches in length, offering a compact profile that fits tight engine bays without sacrificing strength.

In addition to its mechanical robustness, the bolt’s black finish provides corrosion resistance, extending service life even in harsh under‑hood environments. The alloy steel composition is carefully heat‑treated to achieve consistent hardness across the entire batch, guaranteeing that every fastener performs to the same exacting standards. The set includes twelve identical bolts, each stamped with the Trans‑Dapt part number 4900, simplifying inventory management for workshops and ensuring quick replacement when needed.

Designed to meet OEM specifications, this bolt conforms to the Grade 4‑9 manufacturer grade and standard screw thread profile, making it a direct replacement for original exhaust header bolts. Its 5/16‑18 thread size and 3/4‑inch length align with the dimensions used by most performance and replacement exhaust systems, reducing the need for additional adapters or modifications. The hex head’s 5‑point drive allows for efficient torque application using standard socket tools, minimizing installation time and the risk of over‑torquing.

The bolt’s weight of 5.5 ounces per piece contributes to a lightweight fastening solution that does not add unnecessary mass to the exhaust assembly. Despite its light weight, the alloy steel material provides exceptional durability, resisting fatigue and deformation under repeated heating and cooling cycles typical of high‑performance engines. This balance of strength and weight makes the bolt suitable for both street‑legal vehicles and race‑track applications where every gram counts.

Customer feedback on major retail platforms rates the bolt at 4.4 out of 5 stars, highlighting its reliability and ease of installation. Users frequently cite the consistent thread engagement and the solid feel of the hex head as indicators of high quality. The product’s best‑seller rank within the automotive performance exhaust header bolts category further confirms its popularity among mechanics and enthusiasts seeking dependable fastening components.

The alloy steel used in this bolt is sourced from domestic manufacturers in the United States, ensuring strict quality control and traceability throughout the production process. Each batch undergoes ultrasonic testing to detect internal flaws, and the final product is coated with a durable black oxide finish that resists oil, coolant, and road salt exposure. This attention to material integrity and protective treatment translates into a fastener that maintains its structural properties over years of service, even under aggressive driving conditions.

Installation of the Trans‑Dapt hex bolt is straightforward for both seasoned technicians and DIY hobbyists. The bolt’s hex head accepts standard 1/2‑inch sockets, allowing the use of common torque wrenches to achieve the manufacturer‑specified tightening torque of 70 lb‑ft. Proper torque ensures a secure joint without risking thread stripping or bolt stretch, which can lead to premature failure. The bolt’s right‑hand thread orientation matches the majority of exhaust system designs, eliminating the need for reverse‑thread components.

For performance enthusiasts seeking to upgrade their exhaust systems, the bolt’s high shear capacity provides confidence during aggressive driving and track sessions. The 60 ksi shear rating exceeds many OEM fasteners, reducing the likelihood of bolt failure under extreme pressure differentials generated by high‑flow headers. Additionally, the bolt’s precise thread pitch and diameter ensure a tight seal, helping to prevent exhaust leaks that can affect engine performance and fuel efficiency.

The bolt’s design also considers thermal expansion characteristics common in exhaust systems. The alloy steel’s coefficient of expansion is matched to typical exhaust pipe materials, reducing the risk of loosening as the system heats up during operation. This compatibility helps maintain a consistent clamp pressure, preventing the bolt from backing out and ensuring the exhaust remains securely attached throughout the vehicle’s lifespan.

When paired with the appropriate torque wrench and a proper washer, the hex bolt delivers a leak‑free seal that contributes to optimal exhaust flow and reduced back‑pressure. This performance benefit can translate into modest gains in horsepower and fuel efficiency, especially in tuned engines where exhaust efficiency is critical. The bolt’s reliable fastening also minimizes the need for frequent re‑torquing, saving time and labor costs for service technicians.

The packaging of the twelve‑bolt set is designed for easy handling and storage. Each bolt is individually wrapped in a protective film to guard against surface scratches, and the entire set is placed in a compact cardboard box measuring 3.2 inches by 2.2 inches by 1.3 inches. This size fits conveniently into standard toolboxes and inventory shelves, allowing quick access when a replacement is required on the shop floor or in the garage.

The bolt’s design also incorporates a precision‑machined hex head that distributes load evenly across the fastening surface, reducing the risk of deformation under high torque. This engineering detail enhances the bolt’s longevity and maintains the integrity of the surrounding components, such as the exhaust flange and mounting brackets. By minimizing stress concentrations, the fastener contributes to a more stable and quieter exhaust system.

Trans‑Dapt’s commitment to sustainability includes responsible sourcing of raw materials and environmentally conscious manufacturing processes. By adhering to industry best practices, the company reduces waste and energy consumption, delivering a product that not only performs well but also aligns with eco‑friendly values. Customers can feel confident that their purchase supports both high performance and responsible production.

The extensive positive reviews and high best‑seller ranking reflect the market’s trust in Trans‑Dapt’s hex bolts. Users consistently report easy installation, reliable holding power, and long‑term durability, making this product a preferred choice for both professional shops and individual car enthusiasts seeking dependable fastening solutions.

Choosing Trans‑Dapt ensures you receive a fastener that combines engineering excellence with practical value for every exhaust project.

Usage

The hex bolt is ideal for installing performance exhaust headers on both domestic and import vehicles. Its robust construction handles the high temperatures generated by turbocharged and naturally aspirated engines, making it suitable for daily driving as well as track days.

Mechanics appreciate the bolt’s compatibility with standard socket sets, allowing quick removal and replacement during routine maintenance or when swapping exhaust components. The 5/16‑18 thread size aligns with most aftermarket header kits, eliminating the need for additional adapters.

DIY enthusiasts can confidently use the bolt for custom exhaust builds, knowing that the Grade 5 hardness provides a balance of strength and ease of installation. The hex head’s 5‑point drive reduces the chance of tool slippage, protecting both the fastener and the mechanic’s tools.

In high‑performance racing environments, the bolt’s ability to maintain torque under extreme vibration and heat ensures that exhaust assemblies stay securely fastened, preventing costly downtime caused by loose or broken bolts.

When retrofitting a vehicle with a larger diameter exhaust, the hex bolt’s 5/16‑18 thread provides the flexibility to accommodate different flange thicknesses. By pairing the bolt with appropriate washers and gaskets, installers can achieve a tight seal that prevents exhaust leaks, which can otherwise lead to reduced engine performance and increased cabin noise. The bolt’s consistent thread pitch also simplifies the alignment of multiple fasteners across the exhaust manifold, ensuring uniform pressure distribution.

For off‑road vehicles that encounter dusty or corrosive environments, the black oxide coating on the bolt offers added protection against rust and wear. Regular inspection and re‑torquing according to the manufacturer’s schedule will keep the fasteners performing at peak efficiency, extending the life of both the bolt and the exhaust system.

In fleet maintenance scenarios, the standardized size and thread of the Trans‑Dapt hex bolt simplify bulk ordering and inventory control. Because the bolt conforms to widely accepted automotive specifications, service managers can stock a single part number for multiple vehicle models, reducing the complexity of parts management. The durability of the alloy steel also means fewer replacements over the vehicle’s service life, translating into cost savings for large-scale operators.

Proper torque application using a calibrated wrench ensures the bolt achieves its designed clamping force, preventing over‑tightening that could strip threads. Following the recommended torque values helps maintain the integrity of the exhaust system and supports optimal engine performance.

Why Choose Us

Trans‑Dapt’s reputation for manufacturing high‑quality fasteners is backed by decades of experience in the automotive industry. Each hex bolt undergoes rigorous testing, including tensile strength and shear resistance assessments, to ensure it meets or exceeds industry standards. This commitment to quality control provides confidence that the bolt will perform reliably in demanding applications.

The alloy steel material is sourced from certified U.S. suppliers, guaranteeing consistent composition and traceability. Heat‑treatment processes are calibrated to achieve Grade 5 hardness, delivering a balance of strength and ductility that resists cracking under thermal cycling. The black oxide finish further protects the bolt from corrosion, extending its service life even in harsh environments.

Customers benefit from Trans‑Dapt’s dedicated support team, which offers technical assistance for installation and troubleshooting. Whether you are a professional mechanic or a home garage hobbyist, the support staff can provide guidance on torque specifications, compatible washers, and best practices to maximize the bolt’s performance. This after‑sales service adds value beyond the product itself.

The twelve‑bolt set is packaged for convenience, with each fastener individually protected to prevent surface damage. This thoughtful packaging reduces waste and ensures that every bolt arrives in pristine condition, ready for immediate use. By choosing this set, purchasers receive a reliable, high‑quality solution that simplifies inventory management and supports efficient installation workflows.

The bolt’s design incorporates a precision‑machined hex head that distributes load evenly across the fastening surface, reducing the risk of deformation under high torque. This engineering detail enhances the bolt’s longevity and maintains the integrity of the surrounding components, such as the exhaust flange and mounting brackets. By minimizing stress concentrations, the fastener contributes to a more stable and quieter exhaust system.

Trans‑Dapt’s commitment to sustainability includes responsible sourcing of raw materials and environmentally conscious manufacturing processes. By adhering to industry best practices, the company reduces waste and energy consumption, delivering a product that not only performs well but also aligns with eco‑friendly values. Customers can feel confident that their purchase supports both high performance and responsible production.

The extensive positive reviews and high best‑seller ranking reflect the market’s trust in Trans‑Dapt’s hex bolts. Users consistently report easy installation, reliable holding power, and long‑term durability, making this product a preferred choice for both professional shops and individual car enthusiasts seeking dependable fastening solutions.

Choosing Trans‑Dapt ensures you receive a fastener that combines engineering excellence with practical value for every exhaust project.

Key Features

• High‑grade alloy steel construction delivers Grade 5 hardness and 60 ksi shear strength for reliable performance under extreme heat and pressure.
• Precision‑machined hex head provides a secure 5‑point drive, reducing tool slippage and ensuring consistent torque application for a tight, leak‑free seal.
• Black oxide coating resists corrosion from oil, coolant and road salt, extending the bolt’s service life in harsh under‑hood environments.
• Standard 5/16‑18 thread and 3/4‑inch length fit a wide range of exhaust headers, eliminating the need for adapters and simplifying installation.
• Dedicated customer support offers technical guidance on torque specs, compatible washers and best practices, ensuring you get optimal performance and after‑sales assistance.

FAQ

Can this bolt be used on both steel and stainless steel exhaust manifolds?

Yes, the Trans‑Dapt hex bolt can be installed on both steel and stainless steel exhaust manifolds. The alloy steel material offers sufficient strength to clamp onto stainless steel surfaces, and the black oxide coating provides a protective barrier against galvanic corrosion. When fastening to stainless steel, it is recommended to use a compatible anti‑seize compound or a stainless steel washer to further prevent corrosion and ensure a secure, long‑lasting connection.

What torque specification should be applied when installing the bolt?

The recommended torque for the 5/16‑18 × 3/4 hex bolt is 70 lb‑ft (95 Nm). Using a calibrated torque wrench ensures the bolt is tightened to the proper clamping force without over‑stretching the threads. Applying the correct torque helps achieve a leak‑free seal and maintains the bolt’s structural integrity, which is especially important for high‑performance exhaust systems that experience significant vibration and thermal cycling.

Is the black coating durable enough for marine or coastal environments?

The black oxide coating on the Trans‑Dapt bolt provides good resistance to rust and corrosion, but for marine or highly salty coastal conditions, additional protection is advisable. Applying a marine‑grade anti‑corrosion spray or using a stainless steel washer can further safeguard the fastener. The underlying alloy steel remains strong, and with proper maintenance, the bolt will continue to perform reliably even in aggressive environments.

Can I purchase replacement bolts individually, or only as a set of 12?

Trans‑Dapt offers the 5/16‑18 × 3/4 hex bolt both as a single unit and in a convenient pack of twelve. Purchasing the full set ensures you have enough fasteners for multiple installations or future replacements, while buying a single bolt is useful for a quick repair. Both options carry the same quality guarantees and are stocked through major automotive distributors.

Overall, the Trans‑Dapt 5/16‑18 × 3/4 hex bolt combines strength, durability and ease of use, making it a smart choice for anyone looking to secure their exhaust system with confidence.

The product comes with a limited lifetime warranty against manufacturing defects, reflecting Trans‑Dapt’s confidence in its engineering. Should any issue arise, customers can contact the support team for a replacement or refund, ensuring peace of mind and continued performance.

Choose quality, choose Trans‑Dapt for lasting exhaust reliability today now.