Complete 3.5K Tandem Axle Suspension Rebuild Kit
Complete suspension rebuild kit for 3,500 lb tandem trailer axle applications using 25.25" double-eye leaf springs, 7-3/4" equalizers, shackles, wet bolts, bronze bushings, hangers, and U-bolt hardware.
Overview
The CSRK-TA-WB-LE-BB-SW4B is a complete tandem axle suspension rebuild kit for compatible 3,500 lb trailer axle suspension setups. This kit brings together the major service parts commonly replaced during a full suspension overhaul, including four double-eye leaf springs, curved equalizers, frame hangers, shackle straps, greaseable wet bolts, flange nuts, bronze bushings, and U-bolt hardware.
R&P Service Insight
A worn tandem axle suspension can lead to sagging, loose tracking, uneven tire wear, excess shackle movement, poor equalizer action, and reduced towing confidence. Rebuilding the full suspension system helps restore geometry instead of chasing one worn part at a time.
- Complete Rebuild Approach: Designed to refresh springs, equalizers, shackles, bushings, bolts, hangers, and U-bolt mounting hardware.
- Wear-Point Coverage: Targets common tandem suspension wear areas including spring eyes, equalizer pivots, shackle straps, and bushing locations.
- Fitment Check Required: Always compare your existing suspension dimensions before ordering or installing.
R&P Knowledge Hub
Compatibility: Intended for compatible 3,500 lb tandem trailer axle suspension applications where the listed spring, equalizer, hanger, bushing, shackle, and U-bolt dimensions match.
Vehicle / System Fit: Tandem axle utility trailers, cargo trailers, equipment trailers, RV-style trailers, and similar double-eye leaf spring suspension systems.
Installation Notes: Verify spring length, spring width, equalizer length, hanger height, shackle strap length, bushing dimensions, axle tube size, and U-bolt configuration before installation.
Performance Insight: A full suspension rebuild can help improve load distribution, axle control, towing stability, braking consistency, and overall road feel.
Brand & Fitment Note
Selling Brand: R&P Carriages curated suspension rebuild kit.
Application Reference: Trailer, RV, axle, and suspension references in this listing describe compatibility or application style only where supported by matching measurements and configuration.
What This Means: This listing is for a complete R&P Carriages curated suspension rebuild kit, not a guaranteed OEM-branded item unless specifically stated and verified.
Before Ordering: Confirm axle rating, spring style, equalizer dimensions, hanger layout, shackle spacing, bushing size, axle tube size, and U-bolt fit before installation.
R&P Repair Insight
This kit is a strong choice when a tandem axle trailer shows suspension wear such as loose shackles, worn bushings, sagging springs, noisy equalizers, axle shift, or uneven ride height. Before disassembly, measure and document the original suspension layout so the new components can be installed in the correct orientation.
- Measure Before Removal: Record hanger spacing, axle position, equalizer orientation, and spring center locations before removing old parts.
- Inspect Mounting Points: Do not install new suspension components into cracked, stretched, or damaged frame hanger locations without correcting the frame issue first.
- Service Wet Bolts: Greaseable wet bolts should be installed correctly and maintained as part of regular trailer suspension service.
Features
Complete Tandem Axle Kit
Includes the main suspension components needed to rebuild a compatible 3.5K tandem axle double-eye leaf spring suspension setup.
Four SW4B Leaf Springs
Includes four SW4B double-eye leaf springs measuring 25.25" long, 1.75" wide, 4-leaf construction, and 1,750 lb rated each.
7-3/4" Equalizer System
Includes two EQ-E1 curved equalizers with a 7-3/4" length for compatible tandem axle suspension layouts.
Wet Bolt & Bronze Bushing Upgrade
Includes greaseable wet bolts, flange nuts, bronze bushings, shackles, hangers, and U-bolt hardware for a more complete suspension service.
Specifications
| Specification | Detail |
|---|---|
| Part Number | CSRK-TA-WB-LE-BB-SW4B |
| Brand | R&P Carriages curated kit |
| Product Type | Complete tandem axle suspension rebuild kit |
| Application | Compatible 3,500 lb tandem trailer axle suspension systems |
| Spring Style | Double-eye leaf spring |
| Spring Measurement | 25.25" long, 1.75" wide, 4-leaf construction |
| Spring Rating | SW4B leaf springs listed as 1,750 lb rated each |
| Equalizer | EQ-E1 curved equalizer, 7-3/4" long |
| Shackle Strap | SL-2.562, 2.562" hole center, 3.75" x 1.25" x .23" |
| Bushing | BU1-1566B bronze spring eye / equalizer bushing, 0.57" x 0.69" x 1.75" |
| Wet Bolt | FA-7-187, hex head wet bolt, 0.56" x 3", 7/16" step-down end |
| U-Bolt Hardware | BOM includes UBK-3500-R kit line plus individual 12N nuts, TP-4 tie plates, and UB-R301 round U-bolts as listed below |
Fitment / Application
| Category | Details |
|---|---|
| Vehicle / System | Tandem axle trailer suspension system |
| Primary Fit | Compatible 3,500 lb tandem trailer axle applications using double-eye leaf springs and matching 7-3/4" equalizer geometry |
| Secondary Fit | Utility trailers, cargo trailers, equipment trailers, RV-style trailers, and similar tandem axle suspension layouts where dimensions match |
| Important Fitment Note | Do not order by axle rating alone. Confirm spring length, spring width, equalizer size, hanger height, shackle length, bushing dimensions, axle tube size, and U-bolt configuration before installation. |
Included Components / BOM
| Quantity | Item |
|---|---|
| 14 | BU1-1566B: Bronze spring eye / equalizer bushing, 0.57" x 0.69" x 1.75" |
| 2 | EQ-E1: Equalizer, 7-3/4" |
| 14 | FA-6-92Z: 7/16" flange nut for greaseable shackle bolts / wet bolts |
| 14 | FA-7-187: Wet bolt, hex head, 0.56" x 3", 7/16" step-down end |
| 8 | SL-2.562: Shackle strap, 2.562" hole center, 3.75" x 1.25" x .23" |
| 4 | SW4B: Leaf spring, double eye, 25.25" long, 4 leaf, 1,750 lb rated each |
| 2 | UBK-3500-R: U-bolt kit, 3.5K, 5-1/2" long U-bolts with U-bolt plates |
| 8 | 12N: U-bolt nut, 1/2"-20 |
| 2 | TP-4: U-bolt tie plate |
| 4 | UB-R301: Round U-bolt, 3" x 6.5" x 1/2"-20 |
