FAW Frame: Why These 14 Critical Assemblies Define Truck Strength

Welcome to this critical technical guide on the FAW Frame (Part No. 2800010-96S). This is the absolute “backbone” of the entire FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This is not just a component; it is the structural foundation upon which every other system is built, from the engine and cab to the suspension and fifth-wheel.

The FAW Frame is a heavy-duty, high-tensile steel “ladder frame.” Its “logic” is to provide immense longitudinal strength (to support weight) and controlled torsional rigidity (to resist twisting). This assembly must handle the entire payload of the trailer, the torque of the engine, and the constant, violent shocks from the road.

This in-depth guide is an essential resource for chassis technicians, fleet managers, and body builders. We will deconstruct the entire FAW Frame assembly into its 14 main component groups, including the main rails, crossmembers, suspension hangers, 5th wheel mounts, and the critical “logic” of its rivet-and-bolt fastener system.

Core Structure: The “Ladder Frame” (2800010-96S)

The ‘Frame & bracket assy’ (2800010-96S) is the FAW Frame itself. This is a classic “ladder frame” design, which consists of two massive, parallel C-channel steel rails that run the entire length of the truck. These “side rails” are the main load-bearing members.

These two rails are connected by a series of lateral “crossmembers,” which form the “rungs” of the ladder. This parts list details the ‘Front crossmember assy’ (2801070-91W) and the ‘Middle crossmember assy’ (2801120-2000). This crossmember system is the core “logic” of the FAW Frame. It provides the crucial **torsional rigidity**—the resistance to twisting.

When a 6×4 tractor articulates over uneven ground (e.g., one front wheel high, one rear wheel low), the entire FAW Frame is subjected to immense twisting forces. Without these crossmembers, the C-rails would twist like ribbons, leading to component failure and unstable handling. The ‘Strengthening plate-front crossmember’ (2801073-22A) provides additional reinforcement at a high-stress point, ensuring the front of the FAW Frame can handle the forces from the engine and cab mounts.

Front-End Mounting Logic: Suspension and Recovery

The front section of the FAW Frame is engineered as the mounting foundation for the entire front end of the truck. The ‘Front bracket-front steel plate spring’ (2902441-91W) is the heavy-duty “hanger” that holds the front of the leaf spring suspension. This is a critical load point that transfers all road shocks into the FAW Frame.

Similarly, the ‘Front shock absorber upper bracket’ (2905411-1086) is the “shock tower” that anchors the top of the shock absorber. These mounting points must be perfectly located and incredibly strong.

This section also includes the ‘Towing pin seat’ (2806051-22A). This is the reinforced “socket” that accepts the truck’s heavy-duty tow pin. This component must be strong enough to withstand the entire weight of the truck being pulled. It is bolted directly to the FAW Frame‘s front crossmember.

Rear Logic: 5th Wheel & Tandem Axle Mounts

The rear half of the FAW Frame is designed to do the heavy work of a 6×4 tractor. The ‘Saddle base plate’ (2801213-52A), along with its ‘Left’ (2801211-2000) and ‘Right’ (2801212-2000) connection plates, forms the mounting base for the **5th wheel** (the “saddle”). This is the platform that accepts the kingpin from the semi-trailer, transferring the trailer’s entire weight and pull-force directly to the FAW Frame.

Just as important is the **tandem axle suspension**. The ‘Balance suspension hanger assy’ (2801170-2000) is the “trunnion” mount. This is the central pivot point for the “walking beam” suspension that connects the two rear drive axles. This assembly, along with its various connection plates (2801173-2000, 2801174-2000, etc.), allows the two rear axles to “articulate” or “walk” over obstacles, ensuring all eight rear wheels remain in contact with the ground for maximum traction. This is the core “logic” of a 6×4 FAW Frame.

The “Logic” of Fasteners: Rivets vs. Bolts

The parts list for the FAW Frame is dominated by a massive quantity of fasteners, and their “logic” is critical. The list includes 30 rivets (‘Flat head rivet’ Q4501436 and ‘Round head rivet’ Q4501434) and well over 100 high-tensile bolts and lock nuts.

**Rivets:** The ‘Flat head rivets’ (平圆头铆钉) and ‘Round head rivets’ (半圆头铆钉) are used for **permanent, high-shear-strength connections**. These are used to attach the main structural crossmembers (like 2801070-91W) to the C-channel side rails. A rivet, when “hot-set,” fills the hole completely and provides a vibration-proof, lightweight, and incredibly strong joint that is superior to a bolt in shear. This is the “permanent” part of the FAW Frame.

**Bolts & Lock Nuts:** The dozens of ‘Hex flange bolts’ (六角法兰面螺栓) and ‘Hex head flange lock nuts’ (六角头凸缘锁紧螺母) are used for components that are **serviceable** or **replaceable**. This includes all the suspension brackets (2902441-91W, 2801170-2000), the 5th wheel “saddle” mounts (2801213-52A), and all the various plumbing and wiring brackets. The “flange” and “lock nut” designs are essential for providing a high clamping force that will not vibrate loose over millions of miles. This “rivet vs. bolt” strategy is the core assembly “logic” of the FAW Frame.

FAW Frame Parts List (Marks 1-14)

The following table provides the complete, detailed breakdown of all 14 component groups identified in the ‘Frame’ (499) diagram for the FAW CA4251P66K24T1A3E5 tractor. This FAW Frame is the foundation of the entire vehicle.

Technical Specifications and Assembly Context

The specifications for the FAW Frame are defined by its function as the structural backbone of a heavy-duty 6×4 tractor. The FAW Frame is engineered for maximum strength and durability using a combination of permanent and serviceable fasteners.