Screw with Seal 8M0058389

Function and Technical Context

This sealing screw acts as a fastening and sealing element in the stern drive and propulsion assemblies, integrating in a single component the structural clamping function and the sealing function through the integral seal. It operates in the propulsion unit under demanding conditions of continuous vibration, repeated thermal cycles and direct exposure to saltwater or freshwater, where any loss of clamping torque or sealing capacity can compromise the integrity of the assembly. The incorporated seal prevents water ingress into the transmission and prevents lubricant leakage from the gearbox, protecting internal components against galvanic corrosion and premature wear. Should this element fail, leakage may occur at the assembly zone, transmission lubricant degradation and, ultimately, severe failures in the propulsion unit that may leave the vessel without propulsion at sea.

When to Replace This Part?

The most common symptoms indicating the need to replace this sealing screw are the presence of moisture or oil traces in the transmission or stern drive area, the appearance of localized corrosion at the fastening point and the inability to maintain the correct clamping torque after adjustment. Visual inspection of this component is recommended at each seasonal maintenance interval and it should be systematically replaced whenever the assembly where it is installed is disassembled, since the seal loses its sealing capacity with successive assembly and disassembly cycles. Replacing this screw preventively during each annual overhaul is the most effective measure to prevent costly repairs due to water ingress or lubricant loss in the transmission.

Compatible Volvo Engines

Mercury / MerCruiser

Equivalent Manufacturer References