Billet Aluminum Trailer Oil Bath Cap 3.5"-12 Thread with Wrench
Billet aluminum oil bath cap kit with wrench for 3.5"-12 threaded hubs. Designed for compatible Dexter 9K–10K axle applications where the thread size and hub configuration match.
Key Measurements & Specs
| Specification | Detail |
|---|---|
| Part Number / SKU | 21-88-BILLET-WRENCH-KIT |
| Product Type | Oil bath cap kit with wrench |
| Thread Size | 3.5"-12 thread |
| Material | Billet aluminum oil cap and billet aluminum wrench |
| Axle Rating Reference | 9K–10K post-July 2009 Dexter axle applications |
| Quantity Included | 1 complete cap and wrench kit |
Fitment / Application
| Category | Details |
|---|---|
| System | Trailer oil bath hub / axle lubrication system |
| Primary Fit | Dexter 9K–10K axle applications, post-July 2009, where a 3.5"-12 oil bath cap is required |
| Fitment Method | Verify thread diameter, thread count, hub style, plug style, and O-ring fit before ordering |
| Important Note | Dexter is used as an application reference only. Confirm your existing cap and hub specifications before installation. |
Top Features
| Feature | Buyer Benefit |
|---|---|
| Billet Aluminum Cap | Durable cap construction for oil bath hub applications |
| 3.5"-12 Thread | Matches compatible threaded hub applications requiring this cap size |
| Center Plug Included | Includes the plug needed for the cap assembly |
| Billet Wrench Included | Provides the matching tool for installation and removal of 2.5" hex caps |
Overview
This billet aluminum oil bath cap kit is built for compatible 3.5"-12 threaded trailer hubs, including listed Dexter 9K–10K post-July 2009 axle applications. The kit includes the oil bath cap, center plug, O-ring, and billet wrench for 2.5" hex caps.
R&P Service Insight
Oil bath caps retain lubricant inside the hub. Correct thread fit, plug condition, and O-ring sealing are important for preventing leaks and protecting bearing performance.
- Thread Check: Confirm that your existing cap uses a 3.5"-12 thread.
- Seal Check: Replace the O-ring when installing the new cap assembly.
- Application Check: Verify axle rating and hub style before ordering.
R&P Knowledge Hub
Compatibility: Fits compatible 3.5"-12 threaded oil bath hub applications. Verify before ordering.
Vehicle / System Fit: Trailer hub oil bath lubrication systems on compatible Dexter 9K–10K axle applications, post-July 2009.
Installation Notes: Clean the hub threads, inspect the sealing surface, install the O-ring correctly, and avoid cross-threading the cap.
Performance Insight: A proper oil bath cap helps retain lubrication inside the hub and supports consistent bearing lubrication during trailer use.
Brand & Fitment Note
Selling Brand: R&P Carriages kit
Application Reference: Dexter axle references describe compatible application fitment only.
What This Means: This listing is for a billet aluminum oil bath cap kit with wrench, not a guaranteed OEM-branded item unless specifically stated and verified.
Before Ordering: Verify thread size, hub style, axle rating, oil bath cap type, center plug style, O-ring fit, and included components before installation.
R&P Repair Insight
Oil bath hub leaks are often related to incorrect cap sizing, damaged sealing surfaces, worn plugs, or O-ring issues. Match the cap by measurement, not by appearance alone.
- Confirm Thread: Match both the 3.5" diameter and 12-thread specification.
- Inspect Hub: Check for damaged threads or sealing surface wear before installation.
- Use Correct Tooling: The included billet wrench is intended for 2.5" hex caps.
Features
Billet Aluminum Construction
Solid billet aluminum oil bath cap construction for compatible trailer hub applications.
3.5"-12 Thread Specification
Designed for hubs that require a 3.5"-12 threaded oil bath cap.
Dexter Application Reference
Listed for compatible Dexter 9K–10K post-July 2009 axle applications where specifications match.
Installation Wrench Included
Includes billet aluminum wrench for installation and removal of 2.5" hex caps.
Included Components
| Part Number | Quantity | Item |
|---|---|---|
| 21-88 | 1 | Billet aluminum oil bath cap, 3.5"-12 thread |
| 046-032-00 | 1 | Center plug |
| 010-050-00 | 1 | O-ring |
| Billet-Wrench-2.5 | 1 | Billet aluminum wrench for 2.5" hex caps |
