Rear brake backing plate for the TRX 300 FourTrax, covering 1988-2000 models in 2WD and 4WD configurations. This aftermarket replacement provides a precise mounting surface for the drum brake shoes, helping restore proper shoe alignment, consistent braking response, and long-term reliability after years of exposure to dirt, moisture, and heat. Designed to fit the TRX 300’s rear drum-brake assembly, it keeps the braking system properly spaced and reduces the risk of shudder or drag caused by a warped or corroded backing plate. OEM reference for cross-checking is 43010-HM5-A10.

In addition to delivering a solid, straight-forward replacement, this part offers real-world value by returning the correct geometry the drum brake relies on for even pad wear and stable coefficient of friction. It’s a reliable choice for trail duty or farm work where mud, grit, and rough terrain can accelerate backing-plate wear, and it pairs well with related hardware to complete a clean, dependable brake job. Note that this is a bare backing plate (no armature, locking pins, or shoe springs) and is commonly paired with accessory hardware like 245.0155 when you’re rebuilding the rear drum brake assembly.

Comprehensive Vehicle Fitment

Manufacturer	Models / Series	Years / Details
Honda	TRX 300 FourTrax (2WD)	1988-2000
Honda	TRX 300 FourTrax (4WD)	1988-2000
Honda	TRX 300 FW (TRX300FW)	1988-2000

Sources confirm broad compatibility across the late-1980s to early-2000 TRX 300 rear-drum brake lineup, including 2WD and 4WD variants.

Product Specifications

Attribute	Details
OEM Reference Part Numbers	43010-HM5-A10; 43100-HC4-010
Type	Rear Brake Backing Plate (drum brake backing plate)
Manufacturer	Aftermarket Replacement
Application	TRX 300 FourTrax 1988-2000 (2WD/4WD)
Material	Steel
Finish	Not specified
Bolt/Hub Details	Not specified
Pairing Notes	Pairs well with 245.0155 hardware kit

Notes: The exact dimensions and bolt-hole pattern are built to fit the TRX 300 rear drum brake housing as specified by the OEM references above. (Cross-check OEM references: 43010-HM5-A10 and 43100-HC4-010.)

OEM & Aftermarket Cross-Reference Information

Part Number	Brand / Type	Cross-Reference Notes
43010-HM5-A10	OEM (Honda)	Primary TRX 300 rear backing plate reference; cross-reference includes 43100-HC4-010 in several catalogs.
43100-HC4-010	OEM (Honda)	Alternative OEM backing plate number used in compatibility listings for the TRX 300 rear brake assembly.
91052-HB3-771	OEM Hardware Reference	Hardware kit component reference appears in related listings; used in some cross-reference sets with the TRX 300 brake assembly.

Cross-reference context is supported by listings that show 43010-HM5-A10 alongside 43100-HC4-010 and related hardware references.

What's Included

This package includes the following component in the box.

• Rear Brake Backing Plate (bare unit)

Armature, brake locking pins, and shoe springs are not included and must be sourced separately if required for your rebuild.

 

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility – designed to align perfectly with the TRX 300 rear drum brake assembly for 1988-2000 models.
• OEM Cross-Reference – aligns with OEM numbers 43010-HM5-A10 and 43100-HC4-010 to ease reference checks.
• Premium Materials – built as a robust steel backing plate to resist corrosion and wear under trail and farm conditions.
• Performance Restoration – brings back correct brake shoe alignment and even wear, improving braking response.
• Cost-Effective – provides a economical alternative to OEM parts while preserving original braking geometry.
• Trail & Farm Reliability – engineered to tolerate dirt, moisture, and heat cycles common in off-road work.

Installation Notes:

• Inspect the drum hub and brake housing for cracks, corrosion, and irregular wear before installing the backing plate.
• Clean all mating surfaces and ensure the mounting area is flat to prevent misalignment.
• Align the backing plate with the drum brake hub before securing; start bolts by hand to avoid cross-threading.
• Check for proper clearance between the backing plate and brake shoes once assembled, and verify free rotation without binding.
• Replace associated hardware as needed (pins, springs, and armature components) to ensure full, reliable operation.
• Recheck brake operation after initial use and perform a light brake-bedding procedure if applicable to your drum setup.

Why Upgrade?

Running a worn or damaged rear backing plate can lead to improper shoe alignment, uneven wear, and compromised braking performance, especially under muddy or dusty conditions. Replacing with this aftermarket backing plate restores correct geometry and consistency, helping you regain reliable stopping power and peace of mind on the trail or around the farm.