NISSAN 40578-VB00B Knuckle Grease Wiper Seal Retaining Plate

The genuine Nissan (SKU: 40578-VB00B, alternative part number: 40578VB005) grease wiper seal retaining plate (GUARD-SEAL) is a premium quality genuine OEM component that is an essential part of the knuckle seal assembly on vehicles equipped with a solid front axle.

Function and Operating Principle

This retaining plate mechanically secures and holds the grease wiper seal (knuckle seal) in position behind the knuckle ball. Its role is to provide uniform clamping force around the circumference of the seal, preventing it from shifting or deforming during steering and suspension articulation. This ensures grease retention inside the knuckle housing and protects internal components (CV joints, bearings) from water, mud, and other environmental contaminants.

Technical Features and Specifications

• Manufacturer: NISSAN (Genuine OEM part)
• Part Number (SKU): 40578-VB00B
• Alternative Part Number: 40578VB005
• Material: High-strength stamped steel with corrosion-resistant coating
• Fitting Position: Front axle, at the rear seal of the knuckle housing
• Design: Curved retaining plate with precision mounting holes for an exact fit

Signs of Failure or Wear

Because the retaining plate is directly exposed to environmental elements, the following issues may arise:

• Corrosion and Rust: Exposure to winter road salt and moisture can thin the metal and cause it to lose its clamping force.
• Mechanical Deformation: Stones or branches kicked up during off-road use can bend the plate, leading to seal loosening.
• Grease Stains Around the Knuckle: If the plate does not adequately secure the seal, lubricating grease will leak out while water and grit penetrate the axle knuckle, causing premature wear to the CV joint.