FAW Power Steering Line: Deconstructing the 23 Critical Hydraulic Components

Welcome to this critical technical guide on the FAW Power Steering Line system (Assembly 536). This is the complete, high-pressure hydraulic steering system for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This is not just a single “line,” but the entire “logic” circuit, including the pump, reservoir, and steering gear, that provides steering assist.

The FAW Power Steering Line system is the critical assembly that multiplies the driver’s steering input, making it possible to turn the front wheels of a heavy-duty truck with minimal effort. This assembly uses a ‘Power steering pump’ (3407020-93W-C00) to pressurize hydraulic fluid, a ‘Steering device’ (3411010A50A) (the steering gear) to convert that pressure into mechanical force, and a series of high-pressure hoses to connect them.

This in-depth guide is an essential resource for professional chassis technicians and parts specialists. We will deconstruct the entire FAW Power Steering Line system into its 23 serviceable components, explaining the function of the pump, the TRW steering gear, the oil tank, the high-pressure and low-pressure hoses, and all the critical brackets and fasteners.

The “Brain”: Power Steering Gear (3411010A50A)

The “brain” and “muscle” of the FAW Power Steering Line system is the ‘Power steering device assembly’ (3411010A50A), also known as the steering gear. The diagram notes this is a TRW-type steering gear, a leader in heavy-duty steering technology. This component is a complex “hydraulic-assist” gearbox.

Its “logic” is to sense the driver’s input and provide the *actual* force to turn the wheels. When the driver turns the steering wheel, they are twisting a “rotary valve” inside the steering gear. This valve senses the “input torque” and instantly directs high-pressure fluid from the pump to one side of an internal piston. This hydraulic pressure (1500+ PSI) is what provides the power, moving the piston, which in turn rotates the “sector shaft” and the “pitman arm” (see Assembly 533), thus turning the front wheels.

This FAW Power Steering Line component is a “recirculating ball” type gear. This design uses ball bearings to “recirculate” in a groove between the worm shaft (from the steering wheel) and the piston “nut.” This logic provides a very smooth, low-friction feel, is incredibly durable, and can handle the severe “kickback” forces from the road without transferring them to the driver’s hands. This steering gear is the heart of the FAW Power Steering Line‘s “assist” logic.

The “Heart”: Power Steering Pump (3407020-93W-C00)

If the steering gear is the “brain,” the ‘Power steering pump assembly’ (3407020-93W-C00) is the “heart.” This is the component that generates the hydraulic pressure for the entire FAW Power Steering Line system.

This is a belt-driven pump (powered by the engine’s main accessory drive) that draws low-pressure fluid from the ‘Power steering oil tank’ (3408010-716) via the ‘Intake pipe assembly’ (3406010-91W). It pressurizes this fluid to a constant high pressure (e.g., 1500-2000 PSI) and sends it to the steering gear via the ‘High-pressure pipe assembly’ (3406030A91W).

The “logic” of this pump is its internal “flow control” and “pressure relief” valves. The flow control valve ensures that the pump provides the *same* amount of assist at engine idle (e.g., parking) as it does at highway speeds. The pressure relief valve prevents the system from “dead-heading” and over-pressurizing (which would burst a FAW Power Steering Line) when the driver holds the wheel at a full-lock turn. A failing pump is typically diagnosed by a loud “whining” noise or a loss of steering assist at low RPMs.

The Reservoir: ‘Power steering oil tank’ (3408010-716)

The ‘Power steering oil tank’ (3408010-716) is the “reservoir” for the FAW Power Steering Line system. It holds the supply of hydraulic fluid (typically ATF or specialized power steering fluid). This component is mounted to the chassis via the ‘Bracket-power steering oil tank’ (3408021-91W).

This tank performs several “logic” functions beyond just holding fluid. First, it allows for fluid expansion and contraction as it heats and cools. Second, it acts as a “deaerator,” allowing any air bubbles trapped in the fluid to rise to the surface and escape. Air in a hydraulic FAW Power Steering Line will cause a “spongy” feel and a “groaning” noise from the pump.

Third, and most importantly, it contains a filter (usually in the return-line port). This filter is the “kidney” of the FAW Power Steering Line. It traps microscopic metal particles (from pump and gear wear) and contaminants. A clogged filter will starve the pump, causing it to fail. A failure to filter the fluid will destroy the high-precision rotary valve inside the steering gear.

The “Lines”: High and Low Pressure Hoses

The FAW Power Steering Line keyword refers to the critical “piping” that connects these components into a sealed, high-pressure circuit.

**’High-pressure pipe assembly’ (3406030A91W):** This is the most critical “line.” It is a multi-layer, wire-mesh-reinforced hose designed to handle the 1500+ PSI pressure from the ‘Pump’ *to* the ‘Steering gear’. A failure or “blowout” of this hose is a catastrophic event, resulting in an immediate and total loss of power assist and a massive, flammable hydraulic fluid leak. This is a key part of the FAW Power Steering Line.

**’Intake pipe assembly’ (3406010-91W):** This is the “suction” hose from the ‘Oil tank’ *to* the ‘Pump’. It is a large-diameter, low-pressure hose, but it must be reinforced to prevent it from *collapsing* under the pump’s vacuum.

**’Return pipe assembly’ (3406440-91W):** This is the “return” line from the ‘Steering gear’ *back to* the ‘Oil tank’. It is a low-pressure line, but it often includes an “in-line” cooler (a small radiator) to cool the hydraulic fluid, which gets extremely hot from being forced through the steering gear’s valving.

This entire FAW Power Steering Line system is sealed with ‘Hose clamps’ (CQ67635B, CQ67627B) on the low-pressure side and ‘Combination seal gaskets’ (3406321A8E) on the high-pressure banjo-bolt fittings.

FAW Power Steering Line Parts List

The following table provides the complete, detailed breakdown of all 23 components identified in the ‘Power Steering Line (TRW Steering Gear)’ (536) diagram for the FAW CA4251P66K24T1A3E5 tractor. This FAW Power Steering Line is a complete hydraulic system.

Technical Specifications and Assembly Context

The specifications for the FAW Power Steering Line system are defined by its function as a complete, high-pressure, hydraulic-assist circuit. The FAW Power Steering Line is a safety-critical system for vehicle control.