Dongfeng VL truck parts Right hydraulic lock bolt assembly 5002175-C4303

Built to withstand the dynamic tensile and shear forces from the hydraulic lock (up to 15kN during suspension locking/unlocking), the bolts are crafted 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 2.5 times the maximum working load of the VL’s hydraulic lock system without deformation or fracture. The washers are made of 304 stainless steel (1.5mm thick) with a hardness of HV 200–250, providing 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 stretching or shearing by 60% under frequent load cycles (e.g., daily suspension adjustments)

Engineered to prevent bolt loosening under the VL’s high-frequency chassis vibration (up to 200Hz during road driving), the assembly integrates multiple anti-looseness features. Each bolt is pre-coated with a high-temp thread-locking adhesive (Loctite 243 equivalent), which cures at room temperature to form a permanent bond that resists vibration-induced thread backoff. Additionally, the assembly includes serrated lock washers (with 30° serrations on the contact surface) that bite into the hydraulic lock housing and chassis, creating mechanical resistance to loosening. Testing confirms the bolts maintain 95% of their initial torque (120 N·m) after 5,000 vibration cycles, ensuring long-term stability of the 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 (8–12μm 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 3 times. The stainless steel washers are polished and passivated to enhance their resistance to pitting corrosion from hydraulic oil leaks. Unlike uncoated or single-layer zinc-plated bolts, this multi-layer protection ensures the assembly remains rust-free even in harsh conditions (e.g., snowy northern regions, coastal areas with high humidity), avoiding seized bolts that complicate maintenance

Designed as a complete, ready-to-install kit, the assembly includes 4 bolts, 4 stainless steel 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 sleeves without cross-threading. The bolt heads are hexagon-shaped (19mm across flats) to fit standard socket wrenches, and the under-head radius is chamfered to prevent damage to the hydraulic lock’s mounting surface. Installation takes 15–20 minutes: align the hydraulic lock with the chassis, place the washers and lock washers, torque the bolts to OEM-specified 120 N·m, and verify no bolt protrusion interferes 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)