

Welcome to this comprehensive technical guide on the Válvulas FAW, Conjuntos de mangueras y accesorios, the complete pneumatic control “logic” system for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This system is the “brains” that controls the “muscle” of the transmission’s range shifter.
El Válvulas FAW, Conjuntos de mangueras y accesorios are a critical, chassis-mounted system. It is responsible for taking the driver’s electronic “high/low range” command, passing it through a set of electro-pneumatic valves, and then routing high-pressure air through a specific set of hoses to the transmission’s sub-box shift cylinder.
This in-depth guide is an essential resource for professional technicians and parts specialists. We will deconstruct the entire Válvulas FAW, Conjuntos de mangueras y accesorios system into its 24 serviceable components, including the main control valves, the air filter, the high/low gear hoses, and all the brackets and fittings.
El “logic” of the Válvulas FAW, Conjuntos de mangueras y accesorios resides in its main control valves. The parts list identifies a ‘Pneumatic directional valve’ (1702355AA9P) and a ‘Control valve assembly’ (1702255AA9P). These are the electro-pneumatic “logic gates” of the system.
These valves are effectively electronic solenoids. When the driver flips the range selector switch (from Low to High), a low-voltage electrical signal is sent to these valves. This signal energizes an electromagnet, which pulls a “spool” o “poppet” valve open. This action, Sucesivamente, releases high-pressure (100+ PSI) air from the truck’s main air system and directs it into a specific port.
This is the “logic”: a small electrical signal from the driver is used to control a large, powerful pneumatic force. These valves are the heart of the Válvulas FAW, Conjuntos de mangueras y accesorios. They are sealed to their mounting bracket by the ‘Gasket-control valve’ (1702281AA9P), which is a critical seal. A leak here will cause the system to lose air pressure and fail to shift. A failure in the electronic solenoid will also render the Válvulas FAW, Conjuntos de mangueras y accesorios inoperable.
Once the control valves have directed the air, el “Manguera” component of the Válvulas FAW, Conjuntos de mangueras y accesorios takes over. The parts list specifically calls out an ‘Intake hose-low gear’ (1702431AA9P) and an ‘Intake hose-high gear’ (1702441AA9P).
These two hoses are the primary “actuación” lines. El “low gear” hose connects to the “push” side of the transmission’s shift cylinder, and the “high gear” hose connects to the “pull” lado (or vice-versa). When the control valve sends air down the ‘Intake hose-high gear’, it pressurizes the cylinder, physically moving the shift fork and engaging the high-range synchronizer.
These are part of a larger network of ‘Intake hoses’ (1702451AA9P, 1702421AA9P, 1702411AA9P) and ‘Elbow joints’ / ‘Pipe joints’ (1702245AA9P, 1702365AA9P, 1702265AA9P, 1702235AA9P, 1702295AA9P). This entire pneumatic “tubería” system is the muscle of the Válvulas FAW, Conjuntos de mangueras y accesorios.
A crack, split, or loose fitting in any of these high-pressure hoses is a critical failure. It will create a high-pressure air leak, which not only prevents the transmission from shifting ranges but also puts a constant, parasitic drain on the truck’s main air brake system, which is a major safety hazard. The integrity of every component in the Válvulas FAW, Conjuntos de mangueras y accesorios is vital.
The pneumatic valves in the Válvulas FAW, Conjuntos de mangueras y accesorios are high-precision components with very tight tolerances. They cannot be fed the “raw” air from the main tanks, which often contains small amounts of rust, humedad, and compressor oil.
The ‘Air filter & joint assembly’ (1702380-A7G) is the “lung” of the system. This is a final, in-line “polishing” filter. It is placed just before the control valves to trap any fine debris or moisture, protecting the solenoids from sticking or failing. This small filter is a key part of the Válvulas FAW, Conjuntos de mangueras y accesorios‘ long-term reliability.
Conversely, the two ‘Breather plug assembly’ (1702165-A8L) units are the “exhaust” ports. When the driver shifts from “Alto” a “Low,” the high-pressure air in the “Alto” hose must be vented *out* to allow the piston to move. These breathers allow the air to escape quickly and silently, while their internal filters prevent dirt and water from being ingested back into the clean side of the Válvulas FAW, Conjuntos de mangueras y accesorios.
El “Fittings” portion of the Válvulas FAW, Conjuntos de mangueras y accesorios refers to the complete mounting system. The ‘Welded bracket assembly’ (1702385AA9P) is the main structural foundation. It is a heavy-gauge steel bracket that bolts to the transmission housing or chassis. This bracket provides a rigid, secure platform to mount the control valves and filters.
This bracket, and all its associated plumbing, is secured with high-tensile fasteners designed to resist vibration. This includes ‘Hex flange bolts’ (Q1841020, Q1840660S), ‘Hex head bolts’ (CQ1500435), ‘Inner hex socket head cap screws’ (Q02180620), and ‘Light spring gaskets’ (Q40404, Q40406).
Finalmente, the hoses are secured with ‘Worm Drive Hose Clamps’ (CQ67622B, CQ67640B) and ‘Hose clamps’ (1702391-A7G). These are critical for creating an air-tight seal at all “push-on” hose connections. A single loose clamp will cause the entire Válvulas FAW, Conjuntos de mangueras y accesorios to fail. This robust hardware is what makes the Válvulas FAW, Conjuntos de mangueras y accesorios a durable, truck-grade system.
The following table provides the complete, detailed breakdown of all 24 components for the Válvulas FAW, Conjuntos de mangueras y accesorios.
| Mark | Número de pieza. | Nombre de la pieza | Cantidad |
|---|---|---|---|
| 1 | 1702385AA9P | Welded bracket assembly | 1 |
| 2 | Q1841020 | Hex flange bolt, coarse rod (Tipo estándar) | 2 |
| 3 | 1702245AA9P | articulación del codo | 1 |
| 4 | 1702355AA9P | Pneumatic directional valve | 1 |
| 5 | Q40404 | Light spring gasket | 1 |
| 6 | CQ1500435 | Hex head bolt | 1 |
| 7 | 1702365AA9P | articulación del codo | 1 |
| 8 | 1702431AA9P | Manguera de admisión – low gear | 1 |
| 9 | 1702441AA9P | Manguera de admisión – high gear | 1 |
| 10 | Q1840660S | Hex flange bolt, coarse rod (Tipo estándar) | 2 |
| 11 | 1702380-A7G | Filtro de aire & joint assembly (as-per-sample) | 1 |
| 12 | 1702391-A7G | Manguera | 1 |
| 13 | Q40406 | Light spring gasket | 2 |
| 14 | Q02180620 | Inner hex socket head cap screw | 2 |
| 15 | 1702295AA9P | U-shaped joint assembly | 1 |
| 16 | 1702451AA9P | Manguera de admisión | 1 |
| 17 | 1702275AA9P | Three-way pipe (T-joint) | 1 |
| 18 | 1702255AA9P | Control valve assembly | 1 |
| 19 | 1702281AA9P | Empaquetadora – control valve | 1 |
| 20 | 1702235AA9P | Straight pipe joint | 1 |
| 21 | 1702421AA9P | Manguera de admisión | 1 |
| 22 | 1702165-A8L | Breather plug assembly | 2 |
| 23 | 1702411AA9P | Manguera de admisión | 1 |
| 24 | 1702265AA9P | articulación del codo | 1 |
The specifications for the Válvulas FAW, Conjuntos de mangueras y accesorios are defined by its function as the pneumatic control system for the transmission’s range shifter. El Válvulas FAW, Conjuntos de mangueras y accesorios system is a critical logic controller.
| Vehicle Application | FAW Jiefang CA4251P66K24T1A3E5 6×4 Tractor |
| Component Group | Válvulas FAW, Conjuntos de mangueras y accesorios |
| System Type | Pneumatic (Compressed Air) Logic System |
| Control Logic | Electro-Pneumatic (Solenoid Controlled) |
| Main Control Valves | ‘Pneumatic directional valve’ (1702355AA9P), ‘Control valve assembly’ (1702255AA9P) |
| Actuation Hoses | ‘Intake hose-low gear’ (1702431AA9P), ‘Intake hose-high gear’ (1702441AA9P) |
| Air Treatment | ‘Air filter & joint assembly’ (1702380-A7G) |
| Venting System | 2x ‘Breather plug assembly’ (1702165-A8L) |
| Mounting System | ‘Welded bracket assembly’ (1702385AA9P) | Rows
| Primary Function | To translate the driver’s electronic range-shift command into a pneumatic force that actuates the sub-box shift cylinder. |
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.