At a Glance
- SKU: 4738-P
PRODUCT INFORMATION
Product Details
Electric Trailer Brake Assembly Kit
Pair – Rockwell 12-1/4" x 3-1/2" Electric Brake Assemblies – 5 Bolt Flange
Complete left and right-hand electric brake assembly pair with cast backing plates for compatible Rockwell-style imported axle applications.
Kit Number: 4738-P Includes 4738-R & 4738-L 12-1/4" x 3-1/2"
Key Measurements & Specs
| Specification | Detail |
|---|---|
| Kit Number | 4738-P |
| Included Part Numbers | 4738-R and 4738-L |
| Brake Size | 12-1/4" x 3-1/2" |
| Brake Type | Electric, self-adjusting |
| Mounting Pattern | 5-bolt flange |
| Quantity Included | Pair: one right-hand and one left-hand assembly |
Fitment / Application
| Category | Details |
|---|---|
| Application | Rockwell-style imported trailer axle brake systems |
| Primary Fit | 12-1/4" x 3-1/2" brakes with 5-bolt mounting flange |
| Fitment Method | Verify brake diameter, shoe width, bolt count, and flange spacing |
| Important Note | Verify before ordering; not confirmed for standard Dexter brake systems |
Top Features
| Feature | Buyer Benefit |
|---|---|
| Matched Pair | Includes both right-hand and left-hand brake assemblies |
| Loaded Backing Plates | Brake components are pre-assembled for faster replacement |
| Cast Construction | Built on cast backing plates for the listed axle style |
| Self-Adjusting Design | Electric brake assemblies with automatic adjustment design |
Overview
The 4738-P kit includes one 4738-R right-hand and one 4738-L left-hand 12-1/4" x 3-1/2" electric brake assembly. These fully loaded assemblies use cast backing plates and a 5-bolt mounting pattern for compatible Rockwell-style imported axle applications.
R&P Service Insight
Brake assemblies in this size family are not universal. Match the brake size, shoe width, and mounting flange before ordering.
- Brake Size: Confirm 12-1/4" diameter and 3-1/2" shoe width.
- Flange Pattern: Verify the 5-bolt mounting flange.
- Axle Style: Confirm Rockwell-style imported axle use.
R&P Knowledge Hub
Compatibility: 12-1/4" x 3-1/2" assemblies differ from 12-1/4" x 3-3/8" and 12-1/4" x 4" brake configurations.
System Fit: Commonly used on imported or Rockwell-style trailer axle brake systems where the brake size and 5-bolt flange match.
Installation Notes: Always verify brake size, bolt count, flange spacing, and left/right orientation before installation.
Performance Insight: Using the correct shoe width and backing plate pattern is critical for proper drum and axle compatibility.
Brand & Fitment Note
Selling Brand: R&P Carriages curated replacement brake assembly kit.
Application Reference: Rockwell-style and imported axle references describe application fitment only.
What This Means: This listing is for a brake assembly pair for compatible applications, not a guaranteed OEM-branded Dexter replacement.
Before Ordering: Verify measurements, mounting pattern, axle style, and included components.
R&P Repair Insight
If your trailer uses a different brake size, shoe width, or mounting pattern, this 5-bolt Rockwell-style assembly may not be the correct replacement. Compare the removed brake assembly before purchase.
- Measure First: Confirm 12-1/4" x 3-1/2" brake size.
- Count Bolts: Match the 5-bolt backing plate flange.
- Check Side: Install the right-hand and left-hand assemblies on the correct side.
Features
Complete Pair
Includes one right-hand 4738-R and one left-hand 4738-L brake assembly.
12-1/4" x 3-1/2" Size
Designed for trailers using this specific brake diameter and shoe width.
5-Bolt Cast Backing Plate
Built for compatible 5-bolt Rockwell-style imported axle flanges.
Loaded Assembly Design
Brake components are pre-assembled on the backing plate for replacement service.
Included Components
| Quantity | Item |
|---|---|
| 1 | 4738-R right-hand 12-1/4" x 3-1/2" electric brake assembly |
| 1 | 4738-L left-hand 12-1/4" x 3-1/2" electric brake assembly |
| Not specified | Additional mounting hardware |
Important Fitment Note: Verify brake size, shoe width, 5-bolt mounting pattern, axle style, included components, and side orientation before ordering or installation.
4738-P 4738-R 4738-L Rockwell 12-1/4 x 3-1/2 electric brake assembly pair 5 bolt flange cast backing plate imported axle trailer brake self adjusting replacement kit R&P Carriages
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.