General Duty 10K GD Trailer Axle Bearing Kit with 21-36 Oil Cap – Pre-2009 Replacement Hub Service Kit
Curated hub service kit for compatible Dexter 10K General Duty axle applications using the 4" 21-36 style oil cap. Built for one hub service position where the listed bearing, race, seal, and oil cap components match your existing axle setup.
Overview
This R&P Carriages bearing replacement kit is assembled for 2013 and older Dexter 10K General Duty axle applications using the 4" 21-36 oil cap style. It brings together the core wear items commonly addressed during oil-bath hub service: bearing cones, matching races, oil seal, and oil cap with plug and O-ring. Use this kit when servicing a compatible 10K General Duty hub where the bearing numbers, race numbers, seal size, and cap style match the parts being removed.
R&P Service Insight
Heavy trailer hubs should not be serviced by guessing from axle capacity alone. A 10K General Duty hub and a 10K Heavy Duty hub can use different component combinations, so the safest fit check is always the part numbers and measurements from the hub being serviced.
- One-Hub Service: This listing is for one bearing replacement kit with one of each listed component.
- Oil Bath Hub Use: Includes a 4" 21-36 oil cap with plug and O-ring for compatible oil-lubricated hub assemblies.
- Critical Fit Warning: This kit is not for Dexter 10K Heavy Duty axle applications.
R&P Knowledge Hub
Compatibility: Designed for 2013 and older Dexter 10K General Duty axle applications where the hub uses the listed bearing/race combination, 3.88" x 2.875" oil seal, and 4" 21-36 oil cap style.
Vehicle / System Fit: Heavy-duty trailer oil bath hub service on compatible 10K General Duty axle assemblies.
Installation Notes: Confirm bearing cone markings, race markings, seal dimensions, oil cap style, and axle type before ordering or installing. Do not order by axle weight alone.
Performance Insight: Replacing bearings, races, seals, and oil cap components together helps avoid reusing worn mating surfaces or old sealing parts during hub service.
Brand & Fitment Note
Selling Brand: R&P Carriages curated service kit.
Application Reference: Dexter names and part references in this listing describe compatibility, fitment target, or application style only where supported by verified component numbers, dimensions, and configuration details.
What This Means: This listing is for an R&P Carriages bearing replacement kit assembled for compatible Dexter-style applications. It is not being sold as a guaranteed Dexter OEM-branded kit unless specifically stated elsewhere and verified.
Before Ordering: Verify axle series, hub style, oil cap size, bearing numbers, race numbers, seal size, and whether your axle is General Duty or Heavy Duty.
R&P Repair Insight
When a hub is opened for bearing service, inspect more than just the bearing cone. The race surface, seal journal, cap threads, cap plug, and oil condition all help tell the story of the hub. If the wrong cap or seal is installed, the hub can leak even when the bearings are correct.
- General Duty vs. Heavy Duty: Confirm the axle is a 10K General Duty axle. This kit will not fit 10K Heavy Duty applications.
- Cap Verification: Match the removed oil cap to the 4" 21-36 style before ordering.
- Bearing Number Check: Match the bearing and race markings from your hub before installation, especially the 25580/25520 and 387A/382A bearing/race families.
Features
Curated Hub Service Kit
Combines the primary bearing, race, seal, and oil cap components needed for one compatible 10K General Duty oil bath hub service position.
Built Around Known Component Numbers
Includes the listed bearing and race families, oil seal size, and 21-36 cap style so buyers can compare against the parts removed from the hub.
Oil Cap Included
Includes a 4" 21-36 oil cap with plug and O-ring, reducing the need to reuse an old cap, plug, or sealing O-ring during service.
Clear Fitment Warning
Intended for compatible Dexter 10K General Duty axle applications only. Not for Dexter 10K Heavy Duty axle applications.
Specifications
| Specification | Detail |
|---|---|
| Part Number | BK4-287-GD+21-36CAP |
| Brand | R&P Carriages |
| Product Type | Bearing replacement kit / oil bath hub service kit |
| Application | 2013 and older Dexter 10K General Duty axle applications using 4" 21-36 oil cap style |
| Oil Cap Style | 4" 21-36 oil cap with plug and O-ring |
| Oil Seal Size | 3.88" OD x 2.875" ID oil seal, TCM #770081 reference |
| Bearing / Race Families | 25580 / 25520 and 387A / 382A style components; verify markings before installation |
| Quantity | One kit with one of each listed component |
| Important Exclusion | Will not fit Dexter 10K Heavy Duty axle applications |
Fitment / Application
| Category | Details |
|---|---|
| Vehicle / System | Heavy-duty trailer oil bath hub assembly |
| Primary Fit | 2013 and older Dexter 10K General Duty axle applications with matching components |
| Required Match Points | 10K General Duty axle, 4" 21-36 oil cap style, listed bearing/race families, and 3.88" x 2.875" oil seal size |
| Does Not Fit | Dexter 10K Heavy Duty axle applications |
| Notes | Confirm all markings and measurements from the original hub components before ordering. Do not rely on trailer model, axle capacity, or visual appearance alone. |
Bill of Materials / Included Components
| Quantity | Component | Identifying Detail | Service Role |
|---|---|---|---|
| 1 | 1.75" bearing cone | 25580 / buyer should verify marking against removed bearing | Outer bearing position on compatible hub assemblies |
| 1 | Bearing race / cup | 25520, matching 25580 bearing family | Matching race surface for the 1.75" bearing family |
| 1 | 2.25" bearing cone | 387A | Inner bearing position on compatible hub assemblies |
| 1 | Bearing race / cup | 382A, matching 387A bearing family | Matching race surface for the 387A bearing |
| 1 | Oil seal | 3.88" OD x 2.875" ID, TCM #770081 reference | Hub oil seal for compatible oil bath applications |
| 1 | Oil cap with plug and O-ring | 4" 21-36 style oil cap | Oil bath cap assembly for compatible hub applications |
