At a Glance
- SKU: 21-88-KIT
PRODUCT INFORMATION
Product Details
Oil Bath Hub Service Kit
3.5" Oil Bath Cap Trailer Axle Dexter 9K 10K Kit with Plug and O-Ring – For 10K GD Axles
Complete oil cap service kit for 21-88 oil bath hub applications. Includes one 3.5" oil bath cap, one sealing O-ring, and one center oil plug for compatible 10K general duty axle setups.
Part Number: 21-88-KIT 3.5" Oil Bath Cap Cap + O-Ring + Plug
Key Measurements & Specs
| Specification | Detail |
|---|---|
| Part Number / SKU | 21-88-KIT |
| Product Type | Oil bath cap service kit |
| Cap Reference | 21-88 / 021-088-00 style oil bath cap |
| Cap Size | 3.5" threaded oil bath cap application |
| Seal / Plug References | 010-163-00 O-ring and 046-032-00 center plug references |
| Quantity Included | One kit: 1 cap, 1 O-ring, 1 plug |
Fitment / Application
| Category | Details |
|---|---|
| System | Oil bath trailer hub / drum systems using 21-88 style caps |
| Primary Fit | Commonly used on 10K general duty axle applications after July 2009 where 21-88 cap fitment is required |
| Fitment Method | Verify the cap number, threaded cap size, hub application, and matching O-ring before ordering |
| Important Note | Not all 10K oil bath hubs use the same cap. Compare the existing cap and seal references before installation |
Top Features
| Feature | Buyer Benefit |
|---|---|
| Complete Service Kit | Includes the cap, O-ring, and center plug needed for a matched oil cap service replacement |
| 21-88 Style Cap | Built for compatible hubs that use the 21-88 / 021-088-00 style oil bath cap |
| Oil Bath Sealing Support | Helps maintain oil retention when the cap, plug, and O-ring are properly installed |
| Shop-Friendly Kit | Keeps the common wear and sealing pieces together for quicker hub service work |
Overview
This 21-88-KIT oil bath cap service kit is assembled for compatible trailer hub applications using a 21-88 style oil bath cap. The kit includes one oil bath cap, one O-ring, and one center plug, making it a practical replacement option when servicing a leaking, damaged, or worn oil bath cap assembly.
R&P Service Insight
Oil bath hubs depend on a clean sealing surface, a properly seated O-ring, and a tight center plug to retain lubricant around the bearings.
- Check the cap number: Match the replacement to the existing 21-88 style cap before ordering.
- Inspect the O-ring groove: Clean old oil, grit, and damaged seal material before installing the new O-ring.
- Confirm oil level: After service, fill and inspect the hub according to the trailer or axle manufacturer’s service procedure.
R&P Knowledge Hub
Compatibility: Designed for compatible 21-88 oil bath cap systems. Verify before ordering if your axle, hub, or cap style differs.
Vehicle / System Fit: Commonly associated with 10K general duty trailer axle oil bath hub applications after July 2009 where 21-88 cap fitment is used.
Installation Notes: Replace the cap, O-ring, and center plug together when the cap assembly is leaking or when the plug and seal are worn.
Performance Insight: A properly sealed oil bath cap helps retain lubricant, protect bearing components, and reduce the chance of oil loss during trailer operation.
Brand & Fitment Note
Selling Brand: R&P Carriages curated service kit
Application Reference: 21-88, 021-088-00, 010-163-00, and 046-032-00 are used as application and component reference numbers for fitment matching.
What This Means: This listing is for one R&P Carriages oil bath cap service kit, not a guaranteed OEM-branded item unless specifically stated on packaging or product labeling.
Before Ordering: Verify cap size, thread style, hub application, O-ring reference, plug reference, and axle/hub compatibility before installation.
R&P Repair Insight
Oil bath cap leaks are often caused by an aged O-ring, damaged plug, cracked cap, dirty sealing surface, or incorrect cap selection. Match the replacement kit carefully before disassembly.
- Cap Fit: Confirm the existing cap uses the 21-88 style replacement before ordering.
- Seal Condition: Replace the O-ring any time the cap is removed for service if the seal is flattened, cut, or brittle.
- Leak Check: After installation, inspect for seepage around the cap body and center plug before returning the trailer to service.
Features
Complete 3-Piece Kit
Includes one oil bath cap, one sealing O-ring, and one center oil plug for a complete cap assembly service.
21-88 Style Application
Designed for compatible hubs that use the 21-88 / 021-088-00 style oil bath cap reference.
Oil Bath Hub Service
Supports proper lubricant retention when installed on the correct hub with a clean sealing surface.
Fitment-Safe Replacement
Best matched by comparing the existing cap number, cap size, O-ring reference, and hub application before ordering.
Included Components
| Quantity | Item |
|---|---|
| 1 | 21-88 style oil bath cap, 3.5" application |
| 1 | 010-163-00 style O-ring for 21-88 cap applications |
| 1 | 046-032-00 style center oil plug |
Important Fitment Note: Verify the existing cap number, threaded cap size, O-ring style, plug style, axle rating, hub type, and oil bath system before installation. 21-88 and related part numbers are used as application references for fitment matching.
21-88 oil bath cap kit, 21-88-KIT, 3.5 oil bath cap, 021-088-00 oil cap, 010-163-00 o-ring, 046-032-00 oil plug, 10K GD oil cap kit, trailer hub oil cap with o-ring and plug, oil bath hub cap replacement, 21-88 trailer axle oil cap kit
Related Parts & Kits
Check fitment, measurements, and kit contents before ordering. Related parts may not be required for your repair.
Looking up part numbers in our catalog…
Your repair list1 item selected
Selected products are added together. Review the cart and verify kit contents to prevent duplicates. Prices and discounts are determined at checkout.
BEHIND THIS LISTING
PHOTOGRAPHY & RESEARCH
Ariah Granados
DIGITAL PRESENTATION & DEVELOPMENT
Ken Martin
ONLINE SALES & QUALITY ASSURANCE
Rayn Fisher
WE’RE HERE TO HELP
Not sure it fits?
Have your SKU or manufacturer part number, photos of the original part and mounting, and any critical measurements ready. Capacity, voltage, or bolt pattern can help too.
815-357-3292 · 270 E Jackson St · Seneca, IL 61360
CUSTOMER REVIEWS
Leave a Google review
Good people. Real trailer work.
Customer feedback summarized from Google and Yellow Pages. Dates are shown where available.
TRAILER PARTSGOOGLE
Ordered trailer repair parts repeatedly; praised fast service, careful packing, and accurate orders.
RV KEYSGOOGLE
Found the correct RV keys at a good price with free shipping; the keys worked as expected.
AXLE & LEAF SPRINGSGOOGLE
Needed an unusual axle and leaf-spring size; the team listened and helped him sort out the fit.
PARTS & SHIPPINGGOOGLE
Praised the OEM and aftermarket selection, discounts, quick shipping, and friendly parts staff.
CUSTOM AXLEGOOGLE
Got the axle he needed right away, set up with a custom spring perch.
WELDINGGOOGLE
Praised the polite staff and quality welding on a project.
GAS STRUTGOOGLE
Replacement struts brought a long-used door back to working order.
CUSTOM TRAILERGOOGLE
Had a trailer built to his needs at a fair price, then found parts for two other trailers in stock.
CUSTOMER SERVICEGOOGLE
Praised the customer service after working with R&P over several years.
GAS SHOCKGOOGLE
Found the gas shock he wanted at a good price with shipping included.
CARGO TIE-DOWNGOOGLE
Received swivel D-rings with backing plates and praised the price, correct order, and service.
PARTS DELIVERYGOOGLE
The right parts arrived the first time, with fast delivery and helpful staff.
PROJECT HELPYELLOW PAGES
Said project advice and prompt shipping helped finish a trailer project.
SHIPPINGYELLOW PAGES
Reported helpful service and fast shipment to Germany.
SUSPENSION KITYELLOW PAGES
Praised a suspension kit, fair pricing, and good parts.
TRAILER CORDYELLOW PAGES
Was pleased with a replacement trailer cord.
SERVICE & PARTSYELLOW PAGES
Noted dependable service and products across repeat visits.
AXLE INSTALLATIONYELLOW PAGES
Said the axle installation fit perfectly and thanked Josh and the crew.
HITCH REPLACEMENTYELLOW PAGES
Praised the crew’s professionalism during a difficult hitch replacement.
PRICE & SERVICEYELLOW PAGES
Liked the product, price, communication, and shipping.
LISTING INFORMATIONYELLOW PAGES
Said the product description explained what would work for the trailer.
PRODUCT & SHIPPINGYELLOW PAGES
Received the item as described with very fast shipping and plans to return.
COMMUNICATION & SHIPPINGYELLOW PAGES
Praised accurate description, quick shipping, and clear communication.
PRICE & PRODUCTYELLOW PAGES
Was happy with the product and its price.
SELLER EXPERIENCEYELLOW PAGES
Called it a pleasure doing business with R&P.
INSTALLATIONYELLOW PAGES
Was pleased with product quality, quick delivery, and an easy installation.
PRODUCTSYELLOW PAGES
Was enthusiastic about the products.
DURABILITYYELLOW PAGES
Was ready to install the product on every trailer they own.
REPEAT CUSTOMERYELLOW PAGES
Expected to buy again after a good experience.
INSTALLED PARTYELLOW PAGES
Reported that the newly installed parts were working perfectly.
REPEAT CUSTOMERYELLOW PAGES
Said things went well, as they had on previous visits.
COMMUNICATION & VALUEYELLOW PAGES
Praised clear communication and fair value.
TRANSACTIONYELLOW PAGES
Said the transaction went as expected.
PRICE & PACKAGINGYELLOW PAGES
Noted good value, careful packing, and fast shipping.
PROFESSIONAL SERVICEYELLOW PAGES
Found the team professional and easy to work with.
COMMUNICATION & SHIPPINGYELLOW PAGES
Praised fast shipping and good communication.
TEAMYELLOW PAGES
Shared appreciation for the owners and their company.
SHIPPINGYELLOW PAGES
Reported prompt shipping and said they would buy again.
CUSTOMER SERVICEYELLOW PAGES
Found R&P easy to deal with.
SERVICEYELLOW PAGES
Praised the people and the service.
FIT & SHIPPINGYELLOW PAGES
Reported a good fit, fair price, accurate listing, and quick shipping.
DELIVERYYELLOW PAGES
Received the order a day early and recommended the seller.
CUSTOM TRAILERYELLOW PAGES
Described a no-hassle, professional custom-trailer purchase.
TRAILER PURCHASEYELLOW PAGES
Praised a new trailer, custom additions, helpful staff, and clear pricing.
HUB COVERSYELLOW PAGES
Found the right hub covers quickly and got helpful maintenance advice.
AXLE HELPYELLOW PAGES
Said R&P helped their company get back on the road after an axle problem.
DUMP TRAILERYELLOW PAGES
Was happy with a dump-trailer purchase after comparing options.
BRAKES, DRUMS & SEALSYELLOW PAGES
Received clear help choosing brake assemblies and bearing seals, followed by fast shipping.
DUMP TRAILERYELLOW PAGES
Found a good deal on a 16-foot dump trailer and planned to return.
FRIENDLY SERVICEYELLOW PAGES
Thanked the staff for their patience and recommended the shop.
Showing 3 of 50
Need help with this part? Send photos, part numbers, and measurements. We’ll help you narrow it down.