Dongfeng KL truck parts lower Installation of beam assembly on the front roof 5704925-C3300

As a key load-bearing component for the front roof’s lower section, this beam assembly features a high-strength design to boost structural integrity. The main body is crafted from Q700 high-strength steel via precision stamping, with a 4mm-thick web and 6mm-thick flanges, enhancing the lower roof’s anti-bending and anti-torsion performance by 55% compared to conventional beams. It effectively distributes loads from the upper roof, such as snow accumulation (up to 300kg) and roof accessory weight, to the A-pillars and windshield frame. The beam’s C-shaped cross-section optimizes force transmission, limiting lower roof deflection to ≤1.5mm under static load—preventing deformation that could damage the roof lining or windshield seal

Engineered to serve as an integration hub for front roof lower accessories, the 5704925-C3300 beam features dedicated mounting structures for critical components. It includes reinforced bosses for installing the interior sun visor (Dongfeng OE 5305120-C3300), overhead control panel (Dongfeng OE 5305130-C3300), and interior light (Dongfeng OE 3777010-C3300). Each mounting point has a 8mm-thick steel reinforcement pad, capable of withstanding repeated use forces (e.g., sun visor rotation) without cracking. The beam also integrates built-in wire troughs (15mm width) to organize the electrical harnesses of interior components, avoiding wire entanglement and simplifying maintenance—eliminating the need for aftermarket wire clips that damage the roof inner panel

Optimized to resist corrosion from both cab interior moisture and exterior environmental factors, the beam assembly adopts a dual-layer protective coating system. The surface undergoes phosphatization (12μm thickness) for rust priming, followed by a cathodic electrophoretic coating (30μm thickness) that forms a seamless anti-corrosion barrier. The interior-facing side is further coated with a sound-absorbing powder layer (25μm thickness) that reduces noise transmission. This coating system passes 1800-hour neutral salt spray testing (ASTM B117) with no rust, adapting to humid cab environments and external rain/snow exposure. Welding joints are sealed with anti-corrosion sealant, preventing moisture ingress and extending service life to ≥700,000km

This front roof lower beam assembly is designed for efficient installation and long-term cost savings for Dongfeng KL operators. The pre-assembled structure (beam + reinforcement pads + mounting hardware) allows a two-person team to complete installation in 2.5 hours using standard welding tools and torque wrenches—no on-site cutting or drilling required. The OE-compatible design avoids misalignment issues common with aftermarket beams, which often cause roof leaks or interior component malfunctions (repair costs up to $1,200). By enhancing lower roof rigidity, it reduces maintenance frequency for roof interior accessories and extends the cab’s service life by 25%. Backed by a 3-year/400,000km Dongfeng warranty, it provides reliable structural support and predictable maintenance expenses for fleet operations