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The ZQ32808 Type 1 Non-Metallic Insert Hex Lock Nut (commonly known as a nylon‑insert lock nut) is a critical component in SINOTRUK Sitrak assemblies where vibration and thermal cycling could otherwise loosen standard fasteners. Its design incorporates a durable nylon ring near the top of the nut that deforms elastically over the mating threads, creating a prevailing torque that resists back‑off. This locking mechanism does not rely on thread deformation, allowing repeated reuse without significant loss of performance (though OEM recommends single‑use in safety‑critical applications).
Each ZQ32808 nut is manufactured from high‑strength carbon steel, heat‑treated to meet or exceed Grade 10 (ISO 898‑2) mechanical properties. The nylon insert is made from a specially formulated polyamide that resists oils, fuels, and most chemicals commonly encountered in heavy truck environments. The hex body is zinc‑plated with a clear trivalent passivation, providing corrosion protection (240‑480 hours salt spray) while maintaining consistent torque‑tension characteristics.
In applications such as spring hangers, suspension links, engine mounts, and crossmembers, the ZQ32808 lock nut eliminates the need for additional locking devices like split washers or adhesives. Its compact design allows for installation in tight spaces, and the uniform clamping force reduces the risk of joint fatigue. Fleet maintenance records show that using genuine OEM lock nuts reduces fastener‑related failures by over 40% compared to aftermarket alternatives.
Nylon insert provides consistent locking torque (0.5‑3 Nm per inch) independent of bolt tension. Resists loosening from vibration, shock, and thermal expansion.
Nylon insert functions from -50°C to +120°C, maintaining locking ability throughout the operating range of heavy trucks. No brittle failure at low temperatures.
Zinc plating + passivation meets 480 h salt spray. The nylon insert also prevents galvanic corrosion by isolating the nut from the bolt in certain conditions.
Rolled threads (ASME B18.16.6) provide consistent strength and reduced stress concentrations. Class 6H tolerance ensures smooth installation on OEM bolts.
The ZQ32808 Type 1 Non-Metallic Insert Hex Lock Nut is used extensively throughout SINOTRUK Sitrak C7H, T7H, A7, and HOWO models. Typical applications include: suspension U‑bolt nuts, spring shackle bolts, crossmember attachments, engine mounting brackets, transmission support bolts, and cab tilt mechanism fasteners. It is designed for use with Grade 10.9 or Grade 12.9 bolts of corresponding thread size (M8, M10, M12, M14, M16, etc. – specific size should be verified). The nut conforms to international standards (DIN 985, ISO 10511) and is interchangeable with those specifications.
For fleet managers, standardizing on genuine ZQ32808 lock nuts ensures that all fasteners meet the original engineering requirements for prevailing torque and tensile strength. Aftermarket nylon‑insert nuts often use lower‑grade steel or inferior nylon that softens at moderate temperatures, leading to loss of locking ability. In contrast, the OEM component is validated through Sinotruk’s fastener test program, which includes 500 hours of vibration testing on a resonant fixture.
When replacing fasteners during chassis repairs, always use the ZQ32808 lock nut in combination with new bolts to ensure proper thread engagement. The nut’s nylon insert can be reused up to three times in non‑critical applications, but for safety‑related joints (steering, brakes, suspension), install a new nut each time. The hex size is standard (e.g., 13 mm for M8, 17 mm for M10, 19 mm for M12), matching standard hand tools.
| Parameter | Specification |
|---|---|
| OEM Part Number | ZQ32808 |
| Product Name | Type 1 Non-Metallic Insert Hex Lock Nut |
| Brand | SINOTRUK Sitrak (Genuine OEM) |
| Thread Size (Nominal) | M10 x 1.5 (common variant; other sizes may exist under same base number) |
| Material | Carbon steel (C35E or equivalent) |
| Strength Grade | Grade 10 (ISO 898-2) |
| Surface Finish | Zinc plated (trivalent passivation), clear |
| Insert Material | Nylon 6/6 (polyamide), UV and oil resistant |
| Prevailing Torque (M10) | 2.0 – 5.0 Nm (after 5 installations) |
| Operating Temperature | -50°C to +120°C |
| Corrosion Resistance | >240 h salt spray (ASTM B117) |
| Thread Class | 6H (ISO 965) |
| Hex Width (M10) | 17 mm (across flats) |
| Height (M10) | 10.0 mm (typical) |
| Standards Met | DIN 985, ISO 10511, ASME B18.16.6 |
* Thread size may vary by application; the ZQ32808 part number typically corresponds to M10×1.5, but verify against original equipment. Always use matching grade bolts.
Installing the ZQ32808 lock nut is straightforward, but attention to detail ensures optimal performance. Start with clean threads on the mating bolt; any dirt or rust can damage the nylon insert. Thread the nut by hand until the insert contacts the bolt threads. Use a properly sized wrench or socket to tighten to the specified torque (for M10, typically 40–50 Nm for Grade 10.9 bolts). Do not exceed the torque; the locking function does not require extra torque. The nut will feel slightly stiffer during installation due to the insert, which is normal.
If the ZQ32808 nut must be removed, inspect the nylon insert for wear. If the insert shows cracking, discoloration, or if the prevailing torque drops below 1.0 Nm for M10, replace the nut. In safety‑critical applications (steering, brakes, suspension), always install a new nut. For non‑critical joints, the nut can be reused up to three times provided the insert remains intact and the nut shows no signs of thread damage. After multiple reuses, the nylon may lose its elastic memory; therefore, OEM recommends replacement.
Routine inspections should include checking for rust, especially on the exposed hex faces. If corrosion is present, replace the nut to maintain corrosion protection and to ensure that the nylon insert has not been affected by moisture ingress. For trucks operating in corrosive environments, consider replacing all lock nuts during major chassis overhauls. Proper torque markings (paint marks) help identify any loosening during pre‑trip inspections.
The market is flooded with counterfeit nylon‑insert lock nuts that use substandard materials. Low‑grade steel may not achieve Grade 10 strength, leading to thread stripping under load. The nylon insert in cheap nuts often melts or softens at moderate temperatures (e.g., near exhaust manifolds or brake components), causing complete loss of locking ability. Genuine ZQ32808 nuts are manufactured from certified steel and undergo 100% inspection of insert torque and dimensional conformance.
In addition, the plating on genuine nuts provides superior corrosion resistance. Aftermarket parts often have thin, porous zinc that rusts within months, leading to seized threads and difficult removal. Using OEM lock nuts reduces maintenance time and the risk of fastener failure. Fleet cost analysis shows that initial savings on cheaper nuts are quickly negated by premature re‑torquing, rusted fasteners, and potential component damage from loosening.
SINOTRUK genuine fasteners come with full traceability and are backed by the manufacturer’s warranty. When you choose ZQ32808, you are using the same fastener that originally secured your Sitrak truck from the factory. This consistency ensures that every joint performs as designed, contributing to the overall safety and longevity of the vehicle.
The ZQ32808 Type 1 Non-Metallic Insert Hex Lock Nut is a proven solution for vibration‑prone fastening on SINOTRUK Sitrak trucks. Its robust construction, reliable locking performance, and corrosion resistance make it the preferred choice for maintenance professionals. By using genuine parts, you ensure that every fastener meets the strict quality standards required for heavy‑duty commercial vehicles. Stock ZQ32808 in your inventory for chassis, suspension, and engine repairs.