FAW Front Spring Front Bracket Pin Logical Assembly: Why These 5 Critical Components Matter

Welcome to this critical technical guide on the FAW Front Spring Front Bracket Pin Logical Assembly (Assembly 504). This is the complete “fixed” or “front” pivot point assembly for the front leaf springs on the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This is a critical, load-bearing part of the chassis.

The FAW Front Spring Front Bracket Pin Logical Assembly has a vital “logic.” While the *rear* of the leaf spring must swing on a shackle (Assembly 503) to allow for changes in length, the *front* of the spring must be a rigid, fixed anchor. This assembly provides that anchor. It is responsible for handling all the fore-and-aft forces of the front axle.

This in-depth guide is an essential resource for professional suspension technicians and parts specialists. We will deconstruct the entire FAW Front Spring Front Bracket Pin Logical Assembly into its 5 serviceable component types, including the main ‘Pin’ (2902471-240), the critical ‘Grease fitting’ (C070001), and the locking hardware that holds this high-stress pivot together.

Core Component: The Pivot Pin (2902471-240)

The heart of the FAW Front Spring Front Bracket Pin Logical Assembly is the ‘Pin-Front leaf spring rear bracket’ (2902471-240). The parts list calls for two, one for the left and one for the right side of the vehicle. (Note: The part name in the list, “rear bracket,” is a common catalog typo; this is the pin for the *front* bracket, as defined by the assembly title).

This component is the “axle” or “hinge” for the *front* eye of the main leaf spring. It is a massive, solid steel pin, precision-ground to an exact diameter and case-hardened for a durable, wear-resistant surface. It is designed to slide through the main frame hanger (see Assembly 499) and the bushing in the spring’s eye (see Assembly 502).

The function of this pin is to handle 100% of the longitudinal (fore-and-aft) forces acting on the front axle. When the driver hits the brakes, the entire axle tries to “push back,” and this multi-ton force is concentrated on these two pins. When the truck accelerates, the pins “pull” the axle. They also support a significant portion of the truck’s vertical weight. A sheared or severely worn pin in the FAW Front Spring Front Bracket Pin Logical Assembly would cause the front axle to become misaligned, leading to severe steering instability and eventual failure.

The “Logic”: Serviceable Lubrication (C070001)

The most important “logic” of the FAW Front Spring Front Bracket Pin Logical Assembly is that it is a **serviceable** component, not a “sealed-for-life” part. This is indicated by the ‘Straight grease fitting’ (C070001). The list calls for two fittings, a 1:1 ratio with the two main pins.

This “grease fitting” (also known as a “zerk” or “nipple”) is threaded into a pre-drilled channel in the ‘Pin’ (2902471-240). This allows a technician to connect a grease gun during a standard PM (Preventive Maintenance) service and force heavy-duty chassis grease into the pivot point.

This lubrication logic is critical for two reasons:

1. **1. Lubrication:** The grease creates a high-pressure film between the steel ‘Pin’ and the bronze or rubber bushing inside the leaf spring’s eye. This allows the spring to pivot smoothly and silently, preventing the loud “squeaking” and “groaning” characteristic of a dry, metal-on-metal pivot.
2. **2. Contaminant Purge:** This is the most important function. The act of “purging” the joint with new grease forcefully pushes *out* the old, contaminated grease. This purge expels the water, road salt, and abrasive grit that try to work their way into the joint. Without this, the contaminants would turn the grease into a lapping compound, and the water would cause the pin to rust and seize.

A seized pin in the FAW Front Spring Front Bracket Pin Logical Assembly is a critical failure. It prevents the spring from pivoting at all. This results in an incredibly harsh, unyielding ride and will, in a very short time, cause the main leaf spring to snap, a much more expensive failure. Regular greasing of this FAW Front Spring Front Bracket Pin Logical Assembly is the most important maintenance task for the front suspension.

Sealing and Securing Hardware

The FAW Front Spring Front Bracket Pin Logical Assembly is completed by its sealing and securing hardware. The ‘Screw plug’ (2902472-240) works in tandem with the grease fitting. The main ‘Pin’ is likely drilled all the way through for ease of manufacturing. The ‘Grease fitting’ (C070001) is on one side, and this ‘Screw plug’ is on the other. It acts as a cap, sealing the grease channel and forcing the new grease to exit *around* the pin and into the bushing, rather than just taking the easy path and shooting straight out the other side.

The ‘Hex head bolt’ (CQ1511270) and ‘Hex nut’ (CQ34112) are the “locking” fasteners for the FAW Front Spring Front Bracket Pin Logical Assembly. These are not the main bolts that hold the hanger to the frame (those are in Assembly 499), but are the “pinch” bolts.

The ‘Pin’ (2902471-240) typically has a “flat” or “key” on one end. This bolt is passed through the frame hanger and tightened, “clamping” the hanger onto the pin and preventing the *pin itself* from rotating. The “logic” is to force all rotational movement to occur between the *greased pin* and the *spring bushing*, which is the replaceable wear surface. If the pin were allowed to rotate in the frame hanger, it would “oval” the hole in the truck’s chassis, a permanent and catastrophic failure. This bolt-and-nut combination is a simple but critical part of the FAW Front Spring Front Bracket Pin Logical Assembly‘s design.

FAW Front Spring Front Bracket Pin Logical Assembly Parts List

The following table provides the complete, detailed breakdown of all 5 component types (totaling 12 pieces) identified in the ‘Front Spring Front Bracket Pin Logical Assembly’ (504) diagram for the FAW CA4251P66K24T1A3E5 tractor.

Technical Specifications and Assembly Context

The specifications for the FAW Front Spring Front Bracket Pin Logical Assembly are defined by its function as a serviceable, high-load, fixed pivot for the leaf spring suspension.