FAW Carpet And Threshold Strips: The 11 Essential MSUs for a Flawless, Silent Cab

Welcome to this critical component analysis of the FAW Carpet And Threshold Strips (Assembly 692). This is the complete, 11-component-type, “floor finishing” and “entry sealing” system for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This assembly is the “final layer” of the cab’s interior, providing the “logic” for driver comfort, durability, and a premium, finished appearance.

The FAW Carpet And Threshold Strips system is a multi-functional kit. It works *on top of* the ‘Soundproofing Pad’ (Assembly 623) to provide two primary functions. First, the ‘Floor Carpet’ MSUs provide the “comfort and acoustic logic,” acting as a durable wear-surface that also *absorbs* in-cab noise. Second, the ‘Threshold Strip’ MSUs provide the “sealing and protection logic,” locking down the carpet edges and protecting the high-traffic “sill” of the door frame.

This in-depth guide is an essential resource for cab technicians, collision repair specialists, and parts managers. We will deconstruct the entire FAW Carpet And Threshold Strips assembly into its 11 distinct Minimum Serviceable Unit (MSU) types. We will analyze the 4-piece “modular carpet” logic, the critical “scuff plate” logic of the threshold strips, and the 24-piece “polymer-safe” fastener system that ensures a perfect, rattle-free fit.

Core 1: The “Modular Carpet” Logic (MSUs 1-4) (The “Longer” Module)

This group of MSUs forms the “comfort” and “NVH” layer of the FAW Carpet And Threshold Strips system. It is a 4-piece, modular assembly, allowing for precision fit and serviceability.

1. The “Logic” of Modular Design:

The cab floor is a complex, 3D shape with a large transmission tunnel. Manufacturing a single, one-piece molded carpet is inefficient and makes installation impossible without removing the dashboard and seats.

The “logic” of this 4-piece kit is “serviceability.”

• MSU 1: ‘Left floor carpet assy’ (5109215CD04)
• MSU 2: ‘Right floor carpet assy’ (5109222-D04)
• MSU 3: ‘Middle floor carpet-with storage box’ (5109226AD04)
• MSU 4: ‘Rear floor carpet-with 2KW independent heater’ (5109231BD04)

This modular “logic” is a cost-saver. If a driver spills a large amount of oil on the passenger side, the technician only needs to replace the ‘Right floor carpet assy’ (MSU 2), not the entire, expensive, one-piece carpet. The part names also reveal their specific “logic”—MSU 3 is cut to fit the ‘Storage Box’ and MSU 4 is cut to fit the ‘2KW independent heater’, meaning this is a precision, no-trim-required kit.

2. The “NVH & Durability” Logic:

The FAW Carpet And Threshold Strips are not standard “home” carpet. This is a high-grade, automotive-spec MSU.

Durability Logic: The carpet is made from a dense, “tufted,” and “non-loop” (cut-pile) polypropylene fiber. This “logic” is for durability. A “loop-pile” carpet would “snag” on work boots and unravel. This cut-pile design is fused to a heavy-duty, waterproof “mass backing.” This backing prevents abrasion and stops any spilled water from *ever* reaching the ‘Soundproofing Pad’ (623) or the metal floor, preventing mold and rust.

Acoustic Logic: This is the final “NVH” (Noise, Vibration, Harshness) layer. The ‘Soundproofing Pad’ (623) *blocks* low-frequency noise. This carpet’s “logic” is to *absorb* high-frequency noise. The “soft” pile acts as an “acoustic trap,” absorbing in-cab sound (radio, conversation) and high-frequency “tire hiss.” This “anti-echo” logic is what makes the cab quiet and comfortable.

Core 2: The “Scuff Plate” Logic (MSUs 5-8)

This group of MSUs is the “threshold” component of the FAW Carpet And Threshold Strips. This is the “sealing” and “protection” logic for the single highest-traffic area of the truck: the door sill.

MSU 5-8: The “Sill Strip” MSUs (Left & Right, Front & Middle)

• ‘Left door sill front strip’ (5109511-B27)
• ‘Right door sill front strip’ (5109512-B27)
• ‘Left door sill middle strip’ (5109521-B27)
• ‘Right door sill middle strip’ (5109522-B27)

Protection Logic: The “logic” of these four MSUs is to act as a “scuff plate.” This is the part of the cab the driver *steps on* every time they enter or exit. A simple painted metal sill would be “scuffed” to bare metal in weeks. This MSU is a durable, high-impact, textured polymer (ABS) plate that is 100% scuff-resistant and corrosion-proof.

Sealing & Finishing Logic: This is the “anti-rattle” and “finishing” logic. This trim piece provides the *final*, clean edge that “locks down” the ‘Floor Carpet’ (MSUs 1 & 2) and *covers* the ‘Door Sealing Strip’ (Assembly 691). This “logic” prevents the carpet from “bunching up” and ensures the main door seal is not accidentally “kicked” or dislodged by the driver’s boot.

Core 3: The “Vertical Kick” Logic (MSU 11)

The ‘Left side kick panel assy’ (5109240-D04) is the final “trim” MSU in the FAW Carpet And Threshold Strips assembly.

Aesthetic & Protection Logic: This is the “vertical” piece of trim that covers the cab’s “kick panel”—the area in the driver’s footwell next to the door. Its “logic” is purely for protection and aesthetics. It is a high-scuff, high-impact zone that is constantly kicked by the driver’s left foot.

This polymer MSU is tough, textured, and easy to clean. Its secondary “logic” is to hide the “messy” components underneath it, such as the ‘Cab Fuse Box’ (Assembly 585), hood-release cables, and the main ‘Cab Electrical Harness’ (Assembly 577). It is a “service access” panel, designed to be “popped off” by a technician to access these components.

Core 4: The “Polymer-Safe” Fastener Logic (MSUs 9 & 10)

This final group is the “fastening logic” for the entire FAW Carpet And Threshold Strips kit. It is a 24-piece system (12 screws, 12 washers) designed specifically for *polymer-on-metal* mounting.

MSU 9: ‘Cross recessed pan head screw’ (Q2140616F6) – Qty 12

MSU 10: ‘Large washer’ (Q40206F6) – Qty 12

The “Logic” of the Pair: The “logic” here is that these MSUs are used as a *matched set*. The ‘Sill Strips’ (MSUs 5-8) and ‘Kick Panel’ (MSU 11) are “soft” polymer.

A screw head (MSU 9) alone would create a “high-pressure point” and *crack* or *pull-through* the plastic trim.

The ‘Large washer’ (MSU 10) is the “logic” that prevents this. It *distributes* the clamping force of the screw head over a wide surface area, allowing the trim to be fastened securely without being damaged. This 12-point “polymer-safe” fastening logic is what ensures the FAW Carpet And Threshold Strips remain secure, functional, and rattle-free.

FAW Carpet And Threshold Strips Parts List

The following table provides the complete, detailed breakdown of all 11 component types identified in the FAW Carpet And Threshold Strips assembly for the FAW CA4251P66K24T1A3E5 tractor.

Specifications

The specifications for the FAW Carpet And Threshold Strips are defined by its function as a modular, multi-piece system for cab floor comfort, NVH, and protection.