VOLVO STEERING PISTON 3858128 RM3858128

Volvo Steering Piston 3858128 — Power Assist System

The steering piston is an essential hydraulic component in the steering systems of Volvo Penta propulsion units. Its main function is to convert the hydraulic pressure generated by the steering pump into linear mechanical movement, allowing precise actuation of the steering vane. This replacement part is designed to maintain the required sealing tolerances and technical specifications, guaranteeing smooth, responsive steering and no hydraulic leaks throughout its useful life.

Reference 3858128 is compatible with SX and DPS power steering systems mounted on Volvo Penta outboard tails and stern units. This piston is installed inside the hydraulic cylinder of the steering system, where it works under conditions of high pressure and repetitive cycles of extension and retraction. Its design guarantees compatibility with more than 390 engines of the D, V, TSK series and derivatives, offering a reliable replacement solution for recreational and professional boats.

Volvo Penta Engine Compatibility

Compatible Volvo Engines

Equivalent Manufacturer Part Numbers

Technical Features and Specifications

Piston 3858128 meets Volvo Penta technical standards for hydraulic components of steering systems. Its construction includes polished contact surfaces to minimize friction, high-pressure elastomeric sealing rings and a flange design that facilitates mounting and dismounting on the hydraulic cylinder. The material used in its manufacture resists marine corrosion and degradation due to prolonged exposure to synthetic and mineral hydraulic fluids.

The dimensional tolerance of this spare part guarantees a precise fit within the cylinder, avoiding clearances that could cause pressure losses or erratic steering behavior. Its installation requires rigorous cleaning of the hydraulic lines and the use of hydraulic fluid approved by Volvo Penta. The piston is a precision component that cannot be repaired; In case of damage it must be replaced completely.

Compatible Applications and Government Systems

This piston is used in Volvo Penta SX outboard sterndrives, in sterndrives with DPS power steering system and in longer shaft propellers equipped with hydraulic steering cylinders. Compatible engines include petrol (GI, GXI, GLP, GL, OSI) and diesel (D, TSK) versions with powers ranging between approximately 130 and 430 horsepower. Its use is recommended in renovations of steering systems or after the diagnosis of persistent hydraulic leaks in the steering.

For correct installation, it is advisable to consult the specific Volvo Penta service manual for the propulsion unit and change the hydraulic fluid simultaneously. This replacement is supplied without additional mounting accessories; Existing sealing rings should be retained and inspected prior to installation.