The part is the heart of the hydraulic power steering system on the HOWO MAX 4X2 tractor, converting engine mechanical energy into hydraulic pressure for effortless steering control.
This genuine HOWO VANE TYPE PUMP kit includes the left-handed steering vane pump assembly and the critical O-ring seal required for leak-free installation. When you choose authentic Howo Parts, this VANE TYPE PUMP guarantees OE fitment, precise hydraulic performance, and long-term reliability. Below are detailed descriptions of every component included with this VANE TYPE PUMP assembly.
The O-ring seal is a precision-moulded elastomer ring that provides a critical seal between The part and the steering gear or hydraulic line connection. This VANE TYPE PUMP sealing component is made from high-grade FPM (fluorocarbon rubber) material, specifically formulated to resist degradation from power steering fluid, high operating temperatures (up to 150°C), and the chemical additives present in hydraulic oils. The O-ring fits into a machined groove on the pump body and is compressed when the fitting is tightened, creating a positive seal that prevents hydraulic fluid leakage.
A single O-ring seal is supplied with this VANE TYPE PUMP kit, and it must be lubricated with clean power steering fluid before installation to ensure it seats correctly and does not roll or pinch during assembly. Reusing an old O-ring is not recommended, as the rubber takes a compression set and may not provide a reliable seal. Using the genuine O-ring seal supplied with this VANE TYPE PUMP ensures the correct material, dimensions, and sealing performance, preventing fluid loss that could compromise steering assist or cause damage to other hydraulic components. A properly sealed VANE TYPE PUMP maintains system pressure and ensures that the steering response remains consistent and predictable.
VANE TYPE PUMP – genuine HOWO hydraulic steering pump and seal kit for MAX 4X2
This VANE TYPE PUMP utilises a double-acting vane mechanism that delivers smooth, pulsation-free hydraulic flow. The part design ensures consistent steering assist across the entire engine RPM range, from idle to full load.
This VANE TYPE PUMP is specifically configured as a left-handed unit, matching the exact rotation direction and mounting requirements of the HOWO MAX 4X2 MC11 and MC13 engines. The part bolts directly to the engine bracket without modification.
The part incorporates a built-in flow control valve and pressure relief valve. This VANE TYPE PUMP feature automatically regulates output flow and maximum pressure, protecting the steering system from over-pressure and ensuring consistent assistance.
This VANE TYPE PUMP kit includes the factory-specified O-ring seal, ensuring a leak-free installation. Using the correct VANE TYPE PUMP O-ring prevents fluid leaks that could compromise steering performance or damage the pump.
The part is driven directly by the engine via a serpentine belt connected to the crankshaft pulley. As the engine runs, The part rotor spins, drawing low-pressure hydraulic fluid from the steering reservoir through the inlet port.
The rotating vanes trap fluid and carry it around the pump chamber, where it is compressed and pressurised. The part then delivers this high-pressure fluid (typically up to 160 bar) through the outlet port to the steering gear.[reference:0]
Inside The part, a flow control valve monitors the volume of fluid being delivered. As engine speed increases,
the flow control valve in The part restricts excess flow to maintain a steady output, ensuring that steering assistance remains consistent regardless of engine RPM.[reference:1] The pressure relief valve in The part limits the maximum system pressure, protecting the steering gear and hoses from damage in the event of a sudden load spike.[reference:2]
The O-ring seal supplied with this VANE TYPE PUMP is installed at the high-pressure outlet connection,
preventing fluid from escaping at the pump-to-line interface. A properly sealed VANE TYPE PUMP maintains system pressure and ensures that the driver receives immediate and consistent steering assistance. Without a functional VANE TYPE PUMP, the steering would become extremely heavy, making the vehicle difficult to control, especially at low speeds or during parking manoeuvres.[reference:3]
The part for HOWO MAX 4X2 is a left-handed rotation unit, meaning it is designed to rotate counter-clockwise when viewed from the drive end.[reference:4] The part has a nominal displacement of 18.0 ml per revolution, delivering a controlled flow rate of approximately 20 litres per minute at rated engine speeds.
[reference:5] The part is capable of generating maximum pressures up to 160 bar (approximately 2,320 psi), providing ample hydraulic force for the heavy-duty steering requirements of the MAX 4X2.[reference:6] The part operates across a speed range of 500 to 3,200 RPM, ensuring reliable performance during both low-speed manoeuvring and highway cruising.[reference:7]
The part features a precision-machined aluminium housing that is both lightweight and durable, with a corrosion-resistant coating to withstand the harsh under-hood environment. The part inlet port has a thread size of M26 x 1.5, while the outlet port is M18 x 1.5, matching the standard fittings used on the HOWO MAX 4X2 hydraulic system.[reference:8] The part is manufactured to exacting tolerances,
with each unit 100% tested for flow rate, pressure output, and noise levels before leaving the factory.[reference:9] The part is supplied with a 12-month warranty against manufacturing defects, providing peace of mind for fleet operators and owner-operators alike.[reference:10]
Before installing The part, ensure the engine is cool and the vehicle is on level ground. Disconnect the battery negative terminal and relieve the hydraulic system pressure by turning the steering wheel lock-to-lock several times with the engine off. Remove the drive belt from the old VANE TYPE PUMP pulley, then unbolt the pump from its mounting bracket. Carefully disconnect the hydraulic lines from The part, taking care not to damage the fittings. Clean the mounting surface on the engine bracket and inspect The part drive pulley for wear.
Coat the new O-ring seal with clean power steering fluid and install it into the groove on The part outlet port.[reference:11] Position the new VANE TYPE PUMP onto the mounting bracket, insert the mounting bolts, and torque them to specification (typically 40-50 Nm).[reference:12] Connect the hydraulic lines to The part, ensuring the O-ring seal is correctly seated. Reinstall the drive belt and tension it according to the manufacturer’s specification.
Refill the steering reservoir with the correct power steering fluid (Dexron III or equivalent). Start the engine and turn the steering wheel from lock to lock several times to bleed air from The part system. Check for leaks around The part connections and top up the fluid level as needed. The part installation is now complete.
If the steering feels heavy or unresponsive, The part may not be generating sufficient pressure. Check the drive belt tension first; a slipping belt will prevent The part from spinning at the correct speed. If the belt is tight, inspect the hydraulic fluid level in the reservoir; low fluid will cause The part to cavitate,
reducing output and producing a whining noise. A whining or groaning noise from The part often indicates air in the system or a failing pump bearing. Bleed The part system by turning the steering wheel lock-to-lock several times with the engine running. If the noise persists,
The part may have internal wear and should be replaced. Fluid leaks from The part area typically indicate a failed O-ring seal or loose fitting; replace the O-ring and retorque the connection. If The part produces excessive steering effort at idle but works at higher RPM, the flow control valve may be sticking; this usually requires replacement of The part. Always use genuine VANE TYPE PUMP components for repairs to ensure correct fitment and performance.
The part requires regular inspection to ensure long service life. Check the hydraulic fluid level in the steering reservoir every 10,000 km and top up with the correct fluid if needed. Inspect the drive belt for wear and tension at every scheduled service; a loose belt will reduce VANE TYPE PUMP output and cause overheating.
The power steering fluid should be replaced every 100,000 km or every two years, whichever comes first. When replacing the fluid, inspect The part for signs of external leakage, particularly around the shaft seal and the O-ring seal. If The part becomes noisy or the steering response deteriorates,
have the system diagnosed promptly. Using the correct fluid type is critical; incorrect fluid can damage The part internal seals and reduce pump life. Always use genuine VANE TYPE PUMP components when servicing the steering system.
This VANE TYPE PUMP is specifically designed for the HOWO MAX 4X2 tractor, compatible with both MC11 and MC13 engine variants.[reference:13] The left-handed configuration of this VANE TYPE PUMP matches the belt drive arrangement of these engines. The part is also suitable for SITRAK C7H and HOWO T7H models that share the same steering pump mounting and drive system.
The included O-ring seal is a standard fitment for The part outlet connection and is compatible with all HOWO hydraulic steering systems using the M18x1.5 outlet port. This VANE TYPE PUMP kit is not compatible with right-handed pump configurations or with older WD615 engine platforms, which use different mounting brackets and pulley offsets. Always verify your vehicle’s engine type and pump rotation direction before ordering this VANE TYPE PUMP kit.
Aftermarket VANE TYPE PUMP units often use inferior castings, lower-grade seals, and imprecise internal clearances, leading to premature failure, reduced flow, and noisy operation. Generic VANE TYPE PUMP replacements may not have the correct flow control valve calibration, resulting in inconsistent steering assistance or excessive steering effort.
Counterfeit VANE TYPE PUMP O-ring seals may be made from standard nitrile rubber instead of FPM, which hardens and leaks when exposed to hot power steering fluid. A failed VANE TYPE PUMP can cause sudden loss of power steering assistance, making the vehicle extremely difficult to control, particularly in low-speed manoeuvres such as parking or navigating tight spaces. Genuine HOWO VANE TYPE PUMP components are manufactured to SINOTRUK’s exacting standards, using high-grade aluminium castings, precision-ground rotors and vanes, and FPM seals.
The small additional cost of a genuine VANE TYPE PUMP is negligible compared to the safety risk of steering failure or the cost of a towing and repair bill. For fleet operators, using genuine VANE TYPE PUMP units ensures consistent steering feel across the entire fleet and reduces the risk of downtime caused by pump failure.
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