- ChangChun City, Jilin Province, China
by 
This is the essential technical guide to the FAW Front Wheel Assembly (front end accessory drive system) for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This document provides a complete, detailed breakdown of the front-end pulley system, a critical assembly for engine operation.
The function of this system extends far beyond simply spinning. This assembly, referred to here as the FAW Front Wheel Assembly, is responsible for transmitting power from the engine’s crankshaft to all vital accessories, including the alternator, water pump, power steering pump, and air conditioning compressor.
This guide is designed for service technicians, parts departments, and fleet owners, deconstructing the assembly into its smallest serviceable units. We will analyze each component—from the main support bracket and belt to the automatic tensioner and idler pulleys—to ensure accurate diagnostics, maintenance, and parts ordering.
The entire FAW Front Wheel Assembly is built upon two foundational components: the ‘Front Pulley System Bracket’ (1023011-81D) and the ‘Poly-V Belt’ (1023021-81D). The bracket serves as the chassis for the assembly, bolting directly to the engine block. It is a high-strength casting, likely of aluminum or iron, that is precision-machined to provide exact mounting locations for the tensioner and idler pulleys. Its rigidity is essential to prevent flex, which could cause belt misalignment and premature wear.
The ‘Poly-V Belt’ is the component that does the work. As a “poly-v” or multi-ribbed belt, it features multiple small V-shaped ribs. This design offers significant advantages over older, single V-belts. It provides a much larger contact area for grip, allowing it to transmit high loads with less tension and a reduced chance of slippage. This design also allows the belt to be more flexible, enabling it to be routed in complex “serpentine” paths, driving multiple accessories from both its ribbed and flat sides.
Made from durable EPDM (Ethylene Propylene Diene Monomer) rubber, this belt is designed to resist heat, oil, and cracking for tens of thousands of kilometers. However, it is a primary wear item. Regular inspection for cracks, fraying, or glazing is a critical part of vehicle maintenance. A failure of this single belt will result in an immediate loss of power generation (alternator) and engine cooling (water pump), leading to a breakdown.
The single most sophisticated component in the FAW Front Wheel Assembly is the ‘Tensioner Pulley Assembly’ (1023010-36D). This device is critical for the system’s longevity and performance, as it solves a fundamental problem: the belt’s tension must remain constant, even as the belt stretches with age and heat, and as engine loads and RPMs fluctuate rapidly.
This is an automatic tensioner, meaning it is not manually set. Inside the main housing, a powerful, calibrated coil spring is mounted in a cartridge. This spring exerts a continuous, precisely calculated amount of force on an arm, which holds the tensioner pulley. This force automatically “takes up the slack” in the belt, ensuring it remains perfectly tensioned at all times. This prevents slippage, which causes squealing noises and poor accessory performance, and it also prevents over-tensioning, which can destroy the bearings in the alternator or water pump.
Modern tensioners like this one also include an internal damping mechanism. This works like a small, integrated shock absorber, which stops the tensioner arm from “fluttering” or “slapping” during rapid acceleration or deceleration (like shifting gears). This damping is crucial for reducing noise and dramatically extending the life of the belt and the tensioner’s own bearing. The ‘Combination Bolts’ (CQ1460835) are specified for its installation, likely featuring a captive washer for secure mounting.
The entire ‘Tensioner Pulley Assembly’ is considered a single serviceable unit. The two primary failure points are the internal spring (which can weaken over time, leading to a loose belt) and the pulley bearing (which can wear out, causing a grinding or whining noise). When a failure is diagnosed, the entire assembly (1023010-36D) is replaced to restore the FAW Front Wheel Assembly to its original factory specifications.
While the tensioner *applies* pressure, the ‘Idler Pulley Assemblies’ (1023015-36D) *guide* the belt. The parts list calls for two of these units. Unlike the tensioner, these idlers are fixed in place (bolted to the ‘Front Pulley System Bracket’) and do not move. Their purpose is purely directional.
Idler pulleys are used for two main reasons. First, they route the belt around obstacles. The front of an engine is a crowded space with engine mounts, coolant hoses, and other components. The idlers are placed to create a clear, non-interfering path for the belt.
Second, they are used to increase the “wrap angle” on other pulleys. For example, by placing an idler pulley near the alternator, the belt can be forced to wrap more than 180 degrees around the alternator’s pulley. This increased surface contact provides superior grip, allowing the alternator to be driven effectively without belt slippage, even under high electrical load.
Just like the tensioner, the ‘Idler Pulley Assembly’ is a simple device composed of a high-quality pulley (which can be flat or ribbed, depending on which side of the belt it contacts) and an internal, high-speed bearing. The bearing is the only wear item. Failure is typically indicated by a high-pitched whining or grinding sound that rises and falls with engine RPM. If an idler bearing seizes, it will instantly destroy the belt. Therefore, these are critical inspection points when servicing the FAW Front Wheel Assembly.
The integrity of the FAW Front Wheel Assembly is dependent on its fasteners. The parts list identifies two types. The ‘Hex Flange Bolt, Coarse Rod (Standard Type)’ (Q1841075) is a heavy-duty bolt, and the list calls for five. These are almost certainly the main bolts that secure the ‘Front Pulley System Bracket’ (1023011-81D) to the engine block. The flange design is important as it spreads the clamping load over a wider area without needing a separate washer, ensuring the bracket remains rigid and perfectly aligned.
The ‘Combination Bolt’ (CQ1460835), of which there are two, is specified for the ‘Tensioner Pulley Assembly’. A combination bolt typically has a captive washer (either a flat washer or a spring lock washer) pre-installed on the bolt. This simplifies installation and ensures the correct washer is always used, which is vital for a component that is under constant spring-loaded and vibrational stress. Using the correct, factory-specified bolts with the proper torque is not optional; it is mandatory for a safe and reliable repair of the FAW Front Wheel Assembly.
The following table provides the complete, detailed breakdown of all components identified in the ‘Front End Pulley System’ diagram for the FAW CA4251P66K24T1A3E5 tractor. Use these part numbers for accurate ordering and service.
| Mark | Part No. | Part Name | Quantity |
|---|---|---|---|
| 1 | 1023021-81D | Poly-V Belt | 1 |
| 2 | CQ1460835 | Combination Bolt | 2 |
| 3 | 1023010-36D | Tensioner Pulley Assembly | 1 |
| 4 | 1023015-36D | Idler Pulley Assembly | 2 |
| 5 | Q1841075 | Hex Flange Bolt, Coarse Rod (Standard Type) | 5 |
| 6 | 1023011-81D | Front Pulley System Bracket | 1 |
The specifications for the FAW Front Wheel Assembly (accessory drive) are defined by its interconnected components. This system operates as a single unit to power all engine-driven accessories.
| Vehicle Application | FAW Jiefang CA4251P66K24T1A3E5 6×4 Tractor |
| Component Group | Front End Accessory Drive (Pulley System) |
| Main Bracket Part No. | 1023011-81D |
| Belt Part No. & Type | 1023021-81D (Poly-V Belt / Serpentine Belt) |
| Tensioner Assembly | 1x Automatic Spring-Loaded (1023010-36D) |
| Idler Pulley Assemblies | 2x Fixed Idler Pulleys (1023015-36D) |
| Key Fasteners | Q1841075 (5x), CQ1460835 (2x) |
| Primary Function | Transmits rotational power from the crankshaft to engine accessories (e.g., alternator, water pump, power steering pump). |
FAW parts, including the Cylinder Block Assembly, are packaged with care to ensure safe delivery. Each component is secured in protective materials to prevent damage during transit. The logistics network guarantees timely shipments worldwide, supporting efficient maintenance operations. Below is an image illustrating the standard packaging for FAW truck parts, showcasing the attention to detail in handling and storage.
This packaging approach minimizes the risk of corrosion or impact damage, ensuring that parts like the FAW Cylinder Block Assembly arrive in perfect condition. Customers can rely on FAW’s logistics for consistent quality and reliability.
FAW is one of China’s oldest and largest automotive manufacturers, with registered capital of RMB 35.4 billion yuan and total assets of RMB 457.83 billion yuan.
CHINA FAW GROUP CO., LTD. (short for FAW), formerly China First Automobile Works, can trace its roots back to Jul 15, 1953, when its first assembly plant started to be constructed. FAW is one of China’s oldest and largest automotive manufacturers, with registered capital of RMB 35.4 billion yuan and total assets of RMB 457.83 billion yuan.
China heavy truck sales global “five in a row”, heavy truck sales global “six in a row”, tractor sales for 16 consecutive years absolute leading industry.
