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.
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 |
