YUANTUO Trailer Axle Oil Bath Dust Caps Kit — 4pc Clear Polycarbonate, 3.5" Thread (12 TPI) for Dexter 9K–10K Axles

YUANTUO K71-704-00 oil bath dust caps are transparent polycarbonate seals designed to fit Dexter trailer drum assemblies (3.5" thread, 12-thread pitch) and are sold as a 4-piece maintenance kit with plugs and O-rings.

This kit replaces worn or damaged axle dust caps on compatible Dexter 9,000–10,000 lb axles, helping retain lubricant inside the hub and protecting bearings and seals from contamination. Made from clear, durable polycarbonate, each kit includes four 21-88 oil bath caps plus four rubber plugs and four O-rings so you can install them right away. Confirm compatibility with your drum number and manufacturing date before ordering to ensure a proper fit.

Will these dust caps fit my trailer hub?

These caps match specific Dexter drum models produced after certain dates; they are not universal. Verify the drum part number and production date stamped on your drum before purchasing to make sure of a correct fit.

• Compatible with Drum Number 8-415 manufactured after July 2009.
• Compatible with Drum Number 8-430 manufactured after April 2013.
• OE size references: K71-704-00, 3.5" thread outer diameter, 12-thread pitch.
• Sold as a 4-piece kit with extra plugs and O-rings for full axle service.

How do these caps protect my axle and bearings?

The caps create a secure oil-bath seal that helps keep grease or oil inside the hub while preventing water, dirt, and road debris from entering. That protection minimizes wear on bearings, races, and internal seals and supports longer component life when installed and maintained properly.

• Oil-bath design retains lubricant inside the axle housing for consistent lubrication.
• Covers the hub opening to block contaminants and moisture intrusion.
• Includes O-rings for improved sealing and rubber plugs for venting or filling points.
• Clear material allows visual inspection of lubricant level without removal.

What materials and parts are included in the kit?

The components are chosen for durability and straightforward installation. The caps are molded from transparent polycarbonate and the kit ships with matching rubber plugs and O-rings so you can replace all wear items in one service interval.

• Four transparent polycarbonate 21-88 oil bath caps (colorless appearance).
• Four 46-32 rubber plugs for fill/vent ports or secondary sealing.
• Four 10-163 O-rings to ensure a tight, leak-resistant seat.
• Designed for direct-fit installation—no custom machining required.

When should I replace these dust caps?

Replace caps as soon as sealing performance declines or physical damage appears. Routine inspection during wheel service will help you spot cracks, deformation, or major wear that indicate it's time for replacement.

• Replace if visible cracks, deep scratches, or deformation are present.
• Swap during scheduled maintenance when seals or bearings are serviced.
• Replace at the end of the expected service life or if lubricant leakage is detected.
• Regular replacement prevents contamination and extends component life.

Who is this for: This YUANTUO K71-704-00 4-piece oil bath cap kit is intended for trailer owners, fleet maintenance teams, and DIY mechanics working on Dexter 9K–10K axles who need a direct-fit replacement for compatible drum numbers. If you perform regular axle servicing, want a clear cap for quick visual checks, or need a simple, complete kit with plugs and O-rings, this product provides an immediate solution. Always confirm drum part numbers and production dates to ensure compatibility before installation.