- Ville de ChangChun, Province du Jilin, Chine
par 
Welcome to this expert technical guide on the Pompe de direction assistée FAW (Partie no. 3407020-93W-C00), the hydraulic heart of the steering system for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This component is essential for driver control and safety.
The function of the Pompe de direction assistée FAW is to provide hydraulic assistance, reducing the immense physical effort required to turn the front wheels of a fully-loaded tractor. It does this by generating high-pressure hydraulic fluid (often exceeding 1,500 PSI) that is fed to the steering gear.
This in-depth guide is a critical resource for professional technicians and fleet managers. We will deconstruct the entire Pompe de direction assistée FAW mounting assembly into its 3 smallest serviceable units: the main pump, its critical mounting gasket, and the high-tensile fasteners that secure it to the engine.
The main component is the ‘Power Steering Pump Assembly’ (3407020-93W-C00). This is the heart of the hydraulic assist system. For a heavy-duty diesel engine, le Pompe de direction assistée FAW is not a belt-driven accessory as in a passenger car. Instead, it is a robust, gear-driven pump that mounts directly to the engine’s timing gear case. This direct gear-drive is essential for reliability, as it eliminates the risk of a slipping or breaking belt, which would instantly make the truck incredibly difficult to steer.
Ce Pompe de direction assistée FAW is a positive-displacement pump, most likely a high-volume **gerotor** or **vane-type** pump. In a vane pump design, a slotted rotor spins inside an eccentric (off-center) housing. Vanes slide in and out of the rotor slots, creating expanding chambers on the inlet side (which draw in low-pressure fluid from the reservoir) and shrinking chambers on the outlet side. Ce “shrinking” action is what compresses the fluid and generates the high pressure needed for the steering gear.
A critical feature of the Pompe de direction assistée FAW is its internal **flow control valve**. This valve is essential because a gear-driven pump’s output volume increases with engine RPM. If uncontrolled, the steering would be overly sensitive at high speeds and normal at idle. The flow control valve, which is a spring-loaded spool valve, bleeds off excess fluid at higher RPMs, ensuring that the *volume* of fluid sent to the steering gear is constant. This provides a consistent, predictable steering “feel” whether the truck is idling or at highway speed.
Also housed within the Pompe de direction assistée FAW assembly is a **pressure relief valve**. This is a safety poppet valve. When the driver turns the steering wheel all the way to a “lock” (Par exemple, in a parking lot), the steering gear is blocked and can no longer accept fluid. The pressure in the hose would spike almost instantaneously, high enough to rupture the hose or damage the pump. The relief valve senses this pressure spike (Par exemple, >1500 PSI) and opens, dumping the high-pressure fluid directly back to the inlet side, protecting the entire system. Le “whine” you hear when holding the wheel at a full lock is the sound of this valve in operation. A failure of the Pompe de direction assistée FAW often means one of these internal valves has failed, or the gerotor/vane assembly itself is worn out, causing low pressure and stiff steering.
The ‘Gasket-Power Steering Pump’ (3407024-26D) is the single most critical serviceable part in this assembly. Because the Pompe de direction assistée FAW is gear-driven, it mounts directly to the engine’s timing gear case with a flange, just like the fuel injection pump or air compressor. This one gasket must seal this complex interface.
This gasket has two primary, high-stakes functions. First, it must seal the “clean” hydraulic steering fluid from the “dirty” engine oil. The main drive gear of the Pompe de direction assistée FAW is lubricated by the engine’s timing gear case, which is filled with engine oil. The pump’s main shaft must pass through this interface. This gasket (along with a shaft seal) prevents the two fluids from ever mixing. A failure here would contaminate the entire power steering system with abrasive engine oil and soot, destroying the steering gear.
Second, this gasket must also seal the pump’s internal hydraulic passages. Le Pompe de direction assistée FAW‘s flange has a low-pressure “inlet” port (drawing fluid from the reservoir) and a high-pressure “outlet” port (feeding the steering gear). This gasket creates a high-pressure seal for the outlet port, preventing 1,500+ PSI hydraulic fluid from leaking externally.
A failure of this gasket on the inlet side would cause the Pompe de direction assistée FAW to suck in air, leading to cavitation (a loud whining or grinding noise) and foamy, unresponsive steering. A failure on the outlet side would result in a massive, high-pressure hydraulic fluid leak. This gasket is a non-reusable, “replace-on-sight” component.
The final components listed are the two ‘Hex flange bolt, coarse rod (Modèle standard)’ (Q1841030) fasteners. These are the two high-tensile bolts that secure the entire Pompe de direction assistée FAW assembly to the engine’s gear case.
These bolts must perform a critical task: they must provide the precise and even clamping force required to compress the ‘Gasket-Power Steering Pump’ (3407024-26D) and create a perfect seal. En outre, they must resist the immense rotational “shearing” force that the drive gear exerts on the Pompe de direction assistée FAW.
Le “bride” head design is a deliberate engineering choice. The integrated washer head distributes the clamping load over a wider surface area of the pump’s mounting flange. This is critical to prevent the hard steel bolt from cracking the (likely) aluminum pump housing, and it also resists loosening from the constant vibration of the diesel engine. The integrity of the Pompe de direction assistée FAW‘s mount is entirely dependent on these two high-strength bolts.
The following table provides the complete, detailed breakdown of all 3 components identified in the ‘Power Steering Pump’ diagram for the FAW CA4251P66K24T1A3E5 tractor. A professional service of the Pompe de direction assistée FAW requires replacing the gasket.
| Mark | Partie no. | Nom de la pièce | Quantité |
|---|---|---|---|
| 1 | Q1841030 | Hex flange bolt, coarse rod (Modèle standard) | 2 |
| 2 | 3407020-93W-C00 | Power Steering Pump Assembly (as-per-sample) | 1 |
| 3 | 3407024-26D | Pompe de direction-power | 1 |
The specifications for the Pompe de direction assistée FAW are defined by its function as a high-pressure, gear-driven hydraulic pump. The reliability of the Pompe de direction assistée FAW is critical for vehicle control.
| Vehicle Application | FAW Jiefang CA4251P66K24T1A3E5 6×4 Tracteur |
| Component Group | Pompe de direction assistée FAW |
| Main Pump Assembly P/N | 3407020-93W-C00 |
| Pump Type | Positive Displacement (Vane or Gerotor Type) |
| Système d'entraînement | Direct-driven (from Engine Timing Gear) |
| Internal Regulation | Internal Flow Control Valve & Pressure Relief Valve |
| Main Gasket P/N | 3407024-26D (Mounting Flange Gasket) |
| Mounting Fasteners | 2x Hex Flange Bolts (Q1841030) |
| Associated Fluid | Power Steering Hydraulic Fluid |
| Primary Function | Generates high-pressure hydraulic fluid to provide steering assist, reducing driver effort. |
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 est l’un des constructeurs automobiles les plus anciens et les plus importants de Chine., avec un capital social de RMB 35.4 milliards de yuans et actif total en RMB 457.83 milliards de yuans.
CHINE FAW GROUP CO., LTD. (abréviation de FAW), anciennement China First Automobile Works, peut retracer ses racines jusqu'à juillet 15, 1953, lorsque sa première usine d'assemblage a commencé à être construite. FAW est l’un des constructeurs automobiles les plus anciens et les plus importants de Chine., avec un capital social de RMB 35.4 milliards de yuans et actif total en RMB 457.83 milliards de yuans.
Ventes mondiales de camions lourds en Chine “cinq de suite”, ventes de camions lourds dans le monde “six de suite”, ventes de tracteurs pour 16 années consécutives, leader absolu de l'industrie.
