Dongfeng VL truck parts left hydraulic lock bolt assembly 5002170-C4300

Built to withstand the dynamic tensile and shear forces from the left hydraulic lock (up to 14kN during suspension locking/unlocking cycles), the bolts are forged from 40Cr alloy steel and heat-treated to Grade 10.9 standards. This material delivers a minimum yield strength of 900 MPa and tensile strength of 1,040 MPa—capable of withstanding 2.3 times the VL’s hydraulic lock system’s maximum working load without stretching or fracturing. The accompanying washers are made of 304 stainless steel (1.5mm thick) with a hardness of HV 210–250, ensuring uniform pressure distribution between the bolt head and hydraulic lock housing. Compared to Grade 8.8 bolts, this Grade 10.9 design reduces the risk of bolt failure by 65% under frequent load changes (e.g., off-road hauling, slope parking)

Engineered to prevent bolt loosening under the VL’s high-frequency chassis vibration (up to 180Hz during road driving), the assembly integrates dual anti-looseness features. Each bolt is pre-coated with a high-temperature thread-locking adhesive (equivalent to Loctite 243), which cures at room temperature to form a vibration-resistant bond that maintains torque retention. Additionally, the assembly includes serrated lock washers with 30° radial serrations—these bite into the hydraulic lock housing and chassis surface, creating mechanical resistance to thread backoff. Testing confirms the bolts retain 94% of their initial torque (115 N·m) after 6,000 vibration cycles, ensuring long-term stability of the left hydraulic lock connection

Designed to resist corrosion from road salt, mud, and hydraulic oil (common in undercarriage environments), the bolts undergo a zinc-nickel alloy plating process (8–10μm thickness) followed by a clear passivation layer. This coating provides 1,000 hours of neutral salt spray resistance without rust—outperforming traditional zinc plating by 3x and preventing seized bolts during maintenance. The stainless steel washers are polished and passivated to resist pitting corrosion from accidental hydraulic oil leaks. Unlike uncoated bolts, this multi-layer protection ensures the assembly remains functional even in harsh conditions (e.g., snowy northern regions, coastal high-humidity areas) for over 5 years

The assembly is supplied as a complete, ready-to-install kit, including 4 bolts, 4 stainless steel flat washers, and 4 serrated lock washers—eliminating the need for separate part sourcing. Each bolt features precision-machined threads (Class 6g tolerance) with a smooth surface finish (Ra 1.6μm), ensuring easy threading into the chassis without cross-threading. The bolt heads are hexagon-shaped (19mm across flats) to fit standard socket wrenches, and the under-head chamfer prevents damage to the hydraulic lock’s mounting surface. Installation takes 15–20 minutes: clean the mounting area, align the hydraulic lock, install washers and bolts, torque to OEM-specified 115 N·m, and verify no interference with suspension movement. Each unit undergoes torque testing, thread gauge inspection, and corrosion resistance checks, backed by a 24-month warranty against defects (e.g., thread stripping, coating peeling, washer deformation)