FAW J6P Rear Air Vent: Deconstructing 3 Critical Parts for Flawless Cab Pressure Regulation

Welcome to the definitive technical guide for the FAW J6P Rear Air Vent, a vital component for the FAW Jiefang CA3250P66K2L1T1E 6×4 dump truck. This analysis deconstructs the 3 critical parts that form this assembly. This system is essential for operator comfort, pressure equalization, and protecting cab seals.

The FAW J6P Rear Air Vent assembly may seem like a simple part, but it serves a crucial and complex function. Located on the rear wall of the cab, it acts as a one-way check valve, allowing air to escape the cab while preventing dust, water, and exhaust from entering. This guide will break down the assembly, its specialized fasteners, and the logic behind its design.

Core 1: The ‘Pressure Valve’ Logic (The Vent Assembly)

The primary component of this system is the vent assembly itself. It is a pre-built module designed for a specific and critical task: managing air pressure.

1. Component: ‘Rear air vent assembly’ (5610010-A86-C00) – Qty 1
This (Comp 1) is the complete FAW J6P Rear Air Vent assembly. The part number C00 signifies a complete, non-serviceable unit. You cannot buy the internal flaps or seals separately; the entire unit is the serviceable part.

The Pressure Equalization Logic is its most important function. When a driver closes the heavy-duty door of a J6P cab, a large volume of air is compressed. Without an exit path, this pressure spike would make the door extremely difficult to close and would place immense stress on the window seals and door gaskets.

The FAW J6P Rear Air Vent acts as an exhaust port. The sudden pressure pushes the internal flaps open, allowing air to escape instantly. This neutralizes the pressure, allowing the door to close smoothly and securely with minimal effort. This same logic applies to the truck’s powerful HVAC system, giving the fan a place to vent stale air when on fresh-air mode.

The One-Way Valve Logic is what makes this part special. The FAW J6P Rear Air Vent is not just a hole; it is a check valve. The internal flaps, typically made of flexible EPDM rubber, are designed to open outwards only.

This design is critical for a dump truck. When the truck is in motion or on a dusty site, outside air pressure, wind, dust, and water are constantly trying to get into the cab. The flaps are held closed by this external pressure, forming a tight seal. This prevents contaminated air, water from high-pressure washing, and exhaust fumes from being forced *into* the cab, ensuring a clean and safe environment for the driver.

Core 2: The ‘Vibration-Proof’ Logic (The Fastening System)

This group represents the complete fastening system for the FAW J6P Rear Air Vent. The choice of fasteners is a deliberate engineering decision to handle vibration and mixed materials.

1. Component: ‘Cross recessed pan head tapping screw’ (CQ2714816F6) – Qty 1
This (Comp 2) is the primary fastener. It is a “self-tapping” screw, meaning it is designed to cut its own threads into the material it is driven into.

2. Component: ‘Through-hole type insert plastic nut’ (Q39805) – Qty 1
This (Comp 3) is the female counterpart to the screw. It is a “plastic nut,” often called a “grommet nut” or “speed nut.” It is designed to be pushed into a hole in the cab’s sheet metal first.

The Mixed-Material Logic is why this system is used. The FAW J6P Rear Air Vent (Comp 1) is made of plastic (likely ABS or Polypropylene). It is being attached to the painted steel body of the cab. A metal-on-metal fastener system would be problematic.

The plastic nut (Comp 3) is inserted into the steel cab body, providing a non-corrosive, non-conductive plastic thread. The self-tapping screw (Comp 2) then passes through the plastic vent housing and threads *into* the plastic nut.

This isolates all three components. It prevents the screw from scraping the paint off the cab body (which would cause rust) and prevents a steel screw from cracking the plastic housing of the FAW J6P Rear Air Vent. It also prevents galvanic corrosion between different metals.

The Vibration Damping Logic is also key. A rigid metal-to-metal connection would transmit vibration and eventually loosen. The soft, flexible nature of the plastic nut (Comp 3) acts as a thread-locker and a vibration damper, absorbing shocks and keeping the screw from backing out.

Core 3: The ‘Serviceability & Failure’ Logic (The System)

The service life of the FAW J6P Rear Air Vent is defined by its moving parts and its environment. Understanding how it fails is key to correct diagnosis and replacement.

The Failure Mode Logic is straightforward. The primary point of failure is the internal EPDM flaps. Over many years (8-10+), constant exposure to air, temperature cycles, and flexing will cause the rubber to harden, become brittle, or tear.

When this happens, the flaps will no longer create a perfect seal. The driver may report symptoms like a cold draft on their neck, excessive road noise, or the smell of exhaust or dust in the cab. This indicates that the one-way valve has failed and the entire FAW J6P Rear Air Vent assembly must be replaced.

A secondary failure mode is impact damage. Debris from the dumper body or cargo shifting can strike the vent assembly, cracking the plastic housing (Comp 1). This also compromises the seal and requires a full replacement.

The Service Logic is designed for fast replacement. A technician simply removes the interior cab trim, locates the single cross-head screw (Comp 2), and removes it. The old FAW J6P Rear Air Vent assembly can then be pulled out from the cab wall.

Crucially, the plastic nut (Comp 3) must be inspected. These nuts are often brittle with age and can break during removal. It is best practice to replace the plastic nut (Q39805) and the screw (CQ2714816F6) every time a new FAW J6P Rear Air Vent is installed. This ensures the new vent is secured with a fresh, vibration-proof, and corrosion-free fastener, guaranteeing a long-lasting repair.

FAW J6P Rear Air Vent: Complete 3-Part Breakdown

The following table provides the complete, detailed breakdown of all 3 component types in the FAW J6P Rear Air Vent assembly (System 137) for the FAW Jiefang CA3250P66K2L1T1E 6×4 dump truck.

Core Specifications

The specifications for the FAW J6P Rear Air Vent are defined by its role as a one-way pressure valve for the J6P cab.