Integrated Sentinel Oil Hub Cap 5.5in 6-Bolt

Allan Davis on 11/08/2026

Integrated Sentinel oil hub cap 5.5in 6-bolt

Integrated Sentinel Oil Hub Cap 5.5in 6-Bolt

$48.00

Integrated Sentinel oil hub cap for trailer wheel ends using a 5.5in bolt circle and six 5/16in mounting bolts. The 4009 pattern uses a serviceable oil window and matching gasket arrangement for oil-lubricated hubs.

Part number 356-4009.

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Description

Overview

The integrated Sentinel oil hub cap suits trailer wheel ends using the 4009 mounting pattern, a 5.5in bolt circle and six 5/16in mounting bolts. Its Sentinel window combines lubricant viewing with filtered hub-cap protection, so the oil configuration and mounting pattern are the main selection checks.

Features

  • Integrated Sentinel design for oil-lubricated trailer hubs.
  • 5.5in bolt circle with six 5/16in mounting bolts.
  • Serviceable oil window for lubricant-level inspection.
  • 4009 base pattern for matching trailer wheel ends.

Specifications and Materials

The 4009 mounting pattern uses a 5.5in bolt circle with six 5/16in bolts. Overall height is approximately 2-11/16in, while the flange outside diameter is approximately 6-1/4in.

Part number: 356-4009.

See the official STEMCO hub cap installation guide

Compatibility and Fitment

Before fitting, compare the existing hub cap with the 5.5in six-hole mounting pattern and confirm the wheel end uses oil lubrication. Because several hub caps share the 4009 mounting pattern, the Sentinel window configuration also needs to match. These cross-references show where this part replaces the part numbers and applications listed. Some installations may need minor changes. 366-4009, 3664009

Related Parts

Check the related service parts below against the trailer setup before ordering.

Use Part number Part type
Gasket to suit 330-3009 Hub cap gasket
Window kit to suit 359-6145 Integrated Sentinel oil window kit

 

Compliance and Safety

Install the cap on clean, undamaged mounting surfaces with a new gasket. Then tighten the 5/16in fasteners evenly in the recommended sequence and fill the wheel end only to the specified oil level.

Trailer Applications

The integrated Sentinel oil hub cap suits matching trailer axle wheel ends requiring the 4009 six-bolt pattern and oil lubrication.

Cross-reference and Suitability

This part cross-references to or suits the following equivalent part numbers and compatible alternatives:

366-4009 3664009

 

Why Choose ICS Trailers

The quickest identification check is the combination of the 5.5in bolt circle, six mounting holes and Integrated Sentinel oil window. If the original cap is damaged or unreadable, compare the bolt pattern, lubrication type and window arrangement before ordering.

  • The matching gasket can be replaced when the hub cap is removed for service.
  • A separate oil window kit allows the viewing assembly to be repaired without replacing the complete cap.

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