A Critical Analysis: FAW Engine Mounting Bracket Soft Pad Assembly for the CA4251P66K24T1A3E5 Tractor

Welcome to this critical analysis of the FAW Engine Mounting Bracket Soft Pad Assembly, a vital system for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. These components are the essential link between the engine and the truck’s chassis.

This system, the FAW Engine Mounting Bracket Soft Pad Assembly, is not merely a set of supports. It is a highly engineered solution designed to perform two conflicting tasks: it must rigidly hold the entire powertrain in place against massive torque forces, while simultaneously isolating the cab and frame from the intense vibrations of the heavy-duty diesel engine.

This guide is an indispensable resource for technicians, fleet maintenance managers, and parts specialists. We provide a detailed breakdown of the complete assembly, from the primary front and rear soft pad units to the specific high-tensile fasteners that secure them, deconstructed to the smallest serviceable unit.

Front Suspension Bracket Soft Pad Assembly (1001040-92W)

The parts diagram specifies two units of the ‘Front Suspension Bracket Soft Pad Assembly’ (1001040-92W). These are the primary components responsible for controlling the engine’s “torque roll.” A diesel engine produces immense rotational force (torque), and upon acceleration, the entire engine block attempts to twist in the opposite direction.

These front mounts, which are a key part of the total FAW Engine Mounting Bracket Soft Pad Assembly, are specifically designed to be stiff in the lateral and rotational axes to counteract this force. They are constructed as a complex, bonded assembly of high-strength steel brackets and a specially formulated rubber or elastomer compound. This “soft pad” is engineered to absorb the rotational shock, preventing it from being transferred to the chassis while securely anchoring the front of the engine.

Rear Suspension Bracket Soft Pad Assembly (1001060-50A)

Supporting the powertrain from the opposite end are the two ‘Rear Suspension Bracket Soft Pad Assembly’ units (1001060-50A). These mounts are typically located on the transmission housing or the rear of the engine block. Their primary function is different from the front mounts; they are designed to bear the significant static weight of the entire engine and transmission.

These rear mounts are critical for maintaining the precise alignment of the entire powertrain. They ensure the transmission’s output shaft is perfectly angled relative to the driveshaft, preventing driveline vibration and premature wear on U-joints. While the front mounts handle torque, the rear mounts handle vertical load and alignment. Together, these front and rear units create the complete, stable FAW Engine Mounting Bracket Soft Pad Assembly system.

The Science of NVH: How the Soft Pad Assembly Works

The term “Soft Pad Assembly” is a modest description for what is a highly sophisticated piece of engineering. The primary goal of the FAW Engine Mounting Bracket Soft Pad Assembly is to control NVH (Noise, Vibration, and Harshness). A heavy-duty diesel engine, by its very nature, generates intense, low-frequency vibrations. If this energy were bolted directly to the vehicle’s frame, it would create an deafening, bone-jarring ride, and would quickly cause metal fatigue in the cab and chassis components.

These mounts are not simple blocks of rubber. They are often “hydro-mounts” or hydraulic engine mounts. This advanced design features an internal, sealed cavity filled with a special hydraulic fluid. The rubber part of the mount is bonded between two metal brackets (one for the engine, one for the frame) and contains this fluid-filled chamber.

As the engine idles, it vibrates, pushing and pulling on the mount. This action forces the hydraulic fluid back and forth through tiny, precisely-tuned passages or orifices inside the mount. This fluid movement effectively “damps” the vibration, much like a shock absorber smoothing out a bumpy road. This hydraulic damping is extremely effective at isolating the high-frequency vibrations that are most annoying to the driver.

This design gives the FAW Engine Mounting Bracket Soft Pad Assembly dual properties. At idle, when vibration is high but torque is low, the mount is “soft” and isolates the cab. When the truck accelerates, the large engine movement puts pressure on the fluid, which cannot pass through the orifices quickly enough, making the mount temporarily “stiff” to control the engine’s torque-roll.

A failed mount (either from collapsed rubber or a leak in the hydraulic fluid) is a critical issue. It will be immediately noticeable as a severe vibration in the cab at idle, or a loud “clunking” sound when accelerating or decelerating. More importantly, a failed mount forces other components—like radiator hoses, exhaust pipes, and driveshaft yokes—to endure stresses they were not designed for, leading to a cascade of other failures. Replacing worn mounts with the genuine FAW Engine Mounting Bracket Soft Pad Assembly is a critical preventative maintenance task.

High-Tensile Fasteners: Flange Bolts (Q184-TS Series)

A mount is only as strong as the bolts that secure it. The parts list calls for a large number of ‘Hex Flange Bolts, Coarse Rod (Standard Type)’ with the “TS” suffix:

• Q1841440TS (4 units)
• Q1841455TS (4 units)
• Q1841435TS (8 units)

These are not common bolts. The “Flange” design integrates a washer directly into the bolt head, which is essential for spreading the immense clamping force over a wider surface area. This prevents the bolt from damaging the softer metal of the bracket. The “TS” suffix likely indicates a specific high-tensile strength class (e.g., 10.9) and a specialized coating for corrosion resistance. These bolts must endure constant shear forces and vibration. They must be tightened to an exact torque specification to prevent them from loosening or stretching.

Specialized Fasteners: Convex Flange Bolts (Q185-TS Series)

The list also identifies two other specific fasteners: ‘Hex Head Convex Flange Bolt’ Q1851865TS (2 units) and Q1851875TS (2 units). These are different from the standard Q184 series bolts.

A “Convex Flange” bolt, sometimes called a “belled” flange bolt, has a curved or domed flange surface. This design is often used in applications where the bolt needs to self-center within an oversized or slotted hole, or where it must apply pressure at a specific point to lock a component against lateral movement. These four bolts likely serve a unique function within the FAW Engine Mounting Bracket Soft Pad Assembly, perhaps securing a locating pin or a specific sub-bracket that requires this type of specialized fastening.

FAW Engine Mounting Bracket Soft Pad Assembly Parts List

The following table provides the complete, detailed breakdown of all components identified in the ‘Engine Mounting Bracket Soft Pad Assembly’ diagram for the FAW CA4251P66K24T1A3E5 tractor.

Technical Specifications and Assembly Context

The specifications for the FAW Engine Mounting Bracket Soft Pad Assembly are centered on its critical role in NVH (Noise, Vibration, and Harshness) control and powertrain structural support.