The WG9725470088 Power Cylinder is a cornerstone of the Sinotruk HOWO steering assembly. It acts as the primary hydraulic actuator that converts fluid pressure into the mechanical force required to turn heavy-duty front axles under full load.

As a frequently requested Sinotruk spare part, our WG9725470088 is manufactured using high-strength seamless steel tubing and features reinforced piston seals to prevent internal bypass—a common cause of “heavy steering” in older HOWO models. Whether you are navigating construction sites or long-haul highways, this cylinder ensures a responsive and stable steering feel.

Technical Specifications:

Part Number: WG9725470088
Category: Sinotruk Spare Parts / Steering System
Application: Sinotruk HOWO 336/371/420, HOWO A7, HOHAN
Cylinder Bore: 90mm (Standard Precision)
Operating Pressure: Up to 150 Bar
Seal Material: High-temp Resistant Fluororubber (Viton equivalent)
Weight: 14.5 kg
Compatible Fluid: ATF Dexron III or dedicated Hydraulic Steering Oil

Pro-Installation Guide for WG9725470088:

System Flush: Before installing the new Sinotruk spare part, completely flush the steering hydraulic circuit. Old metal shavings or contaminated oil will ruin the seals of your new WG9725470088 within days.
Bleeding the Air: Once the cylinder is mounted, fill the reservoir and cycle the steering wheel from lock-to-lock at least 10 times with the engine off (wheels off the ground). This prevents cavitation and “shuddering” when you first start the engine.
Check the Ball Joints: Inspect the drag link and tie-rod ends connected to the cylinder. A stiff or seized ball joint will put excessive lateral stress on the cylinder rod, leading to premature leaks.
Hose Torque: Use a backup wrench when tightening the hydraulic lines. Over-torquing the fittings can crack the cylinder port housing.
Alignment Post-Install: Since you are replacing a steering actuator, a quick check of the “toe-in” alignment is highly recommended to ensure even tire wear