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OIL BATH HUB SERVICE KIT
Set of FOUR, 21-88 Oil Cap Kit 3.5\" Dexter 10K w/ Plug O-Ring 10-163 46-32
SKU: 21-88-KIT-LOTOF4
Four complete oil bath cap service assemblies with matching O-rings and rubber center plugs for compatible trailer hub applications.
X4 Complete Cap Sets
3.5\" Oil Bath Hubs
21-88 Style Caps
Overview
This listing is for a four-pack oil bath cap kit built around the 21-88 style cap assembly. Each service set includes one oil cap, one matching O-ring, and one rubber center plug. The kit is intended for servicing compatible 3.5\" oil bath trailer hub systems where the existing cap, plug, or seal has become worn, cracked, contaminated, or started leaking.
R&P Service Insight
Oil bath hub caps should be treated as sealing components, not just covers. If the cap or rubber plug is leaking, the bearing cavity can lose oil and take in dirt or moisture.
- Replace as a Set: Cap, O-ring, and plug should be inspected together when oil leakage is present.
- Check the Hub: Verify that the hub threads and sealing surface are clean and undamaged before installation.
- Confirm Size: Match your original 21-88 cap style and 3.5\" oil bath hub application before ordering.
R&P Knowledge Hub
Compatibility: Commonly used with 21-88 / 021-088-00 style oil bath cap applications for compatible 3.5\" trailer hub systems.
Axle Reference: Often associated with many Dexter-style 9K, 10K general duty, and #13G axle applications manufactured after July 2009. Always verify your exact hub and axle setup.
Installation Notes: Clean the cap threads and hub sealing surface. Make sure the O-ring seats correctly and the rubber plug is fully seated after oil inspection or filling.
Performance Insight: A leaking oil bath cap can lead to oil loss, hub contamination, bearing wear, overheating, and premature service failure.
Brand & Fitment Note
Selling Brand: R&P Carriages service kit using 21-88 style replacement oil cap components.
Application Reference: 3.5\" oil bath hubs using 21-88 style threaded oil caps with 010-163-00 O-rings and 046-032-00 rubber center plugs.
What This Means: This listing includes four oil caps, four O-rings, and four rubber plugs — enough to service four compatible oil bath cap assemblies.
Before Ordering: Compare your original cap number, outside diameter, thread style, hub opening, O-ring, and plug style. Trailer axle and hub configurations can vary.
R&P Repair Insight
If oil is collecting around the hub face, cap threads, or rubber center plug, the cap assembly should be inspected immediately. In many cases, the cap itself may be reusable only if the threads and sealing surfaces are clean and undamaged. When in doubt, replacing the cap, O-ring, and plug together is the cleaner service approach.
- Leak Check: Look for oil residue around the cap shoulder, plug opening, and hub face.
- Seal Check: Replace flattened, brittle, swollen, cut, or missing O-rings.
- Plug Check: Replace rubber plugs that are loose, cracked, hardened, or no longer sealing tightly.
Key Features
Four Complete Service Sets
Includes four caps, four O-rings, and four center plugs for servicing four compatible oil bath cap assemblies.
21-88 Style Oil Cap
Designed around the 21-88 / 021-088-00 oil bath cap style used on compatible trailer hubs.
Includes Sealing Components
Each cap includes the required O-ring and rubber plug components for a complete cap service assembly.
Oil Bath Hub Maintenance
Useful for replacing cracked, leaking, worn, missing, or contaminated oil cap components during trailer hub service.
Specifications
Specification
Detail
Primary Cap Number
21-88 / 021-088-00 style
Listing SKU
21-88-KIT-LOTOF4
Brand / Supplier
R&P Carriages service kit
Product Type
Oil bath cap kit
Quantity Included
X4 complete cap assemblies
Application
Compatible 3.5\" oil bath hub systems
Included Seal
010-163-00 / 10-163 style O-ring
Included Plug
046-032-00 / 46-32 style rubber center plug
Fitment / Application
Category
Details
Vehicle / System
Trailer oil bath hub systems
Primary Fit
3.5\" oil bath hubs using 21-88 style caps
Common Uses
Many Dexter-style 9K, 10K GD, and #13G post-July 2009 axle applications
Notes
Verify cap number, hub size, thread style, plug, O-ring, and axle/hub compatibility before ordering.
Detailed Measurements
Key Dimension
Measurement / Detail
Cap Size Reference
3.5\" oil bath cap application
Cap Style
Threaded / screw-in oil bath cap
Seal Reference
010-163-00 / 10-163 O-ring
Plug Reference
046-032-00 / 46-32 rubber center plug
Included Components
Quantity
Item
4
21-88 / 021-088-00 style oil bath caps
4
010-163-00 / 10-163 style O-rings
4
046-032-00 / 46-32 style rubber center plugs
Not Included
Hub, drum, bearings, oil, tools, and additional hardware are not included unless shown or stated otherwise.
Important Fitment Note: Trailer hub and axle configurations can vary. Before ordering, verify your existing oil cap number, 3.5\" cap application, thread style, O-ring, rubber plug, axle model, and hub setup. This kit is intended for compatible 21-88 style oil bath cap applications.
View 21-88 Oil Caps
View 010-163-00 O-Rings
View 046-032-00 Plugs
Need help confirming fitment? Compare your original cap number, hub size, axle type, and sealing components before checkout.
21-88 oil cap kit, 21-88-KIT-LOTOF4, 021-088-00 oil bath cap, 010-163-00 O-ring, 10-163 O-ring, 046-032-00 rubber plug, 46-32 oil plug, 3.5 inch oil bath hub cap, Dexter 10K GD oil cap, Dexter 9K oil cap, #13G axle oil cap, trailer oil bath cap kit
