Front brake caliper piston designed to fit TRX 500 FA (2005-2014), TRX 500 FPA (2005-2014), TRX 500 FE/FM (2005-2011), and TRX 680 FA/FG (2006-2020). This aftermarket piston delivers a precise 34 mm bore and a corrosion‑resistant aluminum profile, ensuring smooth, piston‑to‑bore movement and reliable braking performance. Replacing a worn piston eliminates brake drag, fluid leakage, and inconsistent pad wear, restoring confident stopping power for trail riding and field work.

Over years of mud, water, and grit, worn caliper pistons can corrode, seize, or bind, leading to uneven braking and reduced stopping power. This aftermarket replacement uses a lightweight aluminum alloy with protective plating to resist corrosion and maintain smooth piston action under harsh off‑road conditions. Built to OEM‑style specifications, it’s a dependable choice for riders and farmers who need quick, cost‑effective brake restoration without downtime on the trail or in the field.

Comprehensive Vehicle Fitment

Product Specifications

OEM & Aftermarket Cross-Reference Information

What's Included

This package includes the following components:

• Piston — 34 mm front brake caliper piston

Why Choose This Aftermarket Replacement?

• Direct‑Fit Compatibility: Precisely matched to the 34 mm front caliper piston used on TRX 500 FA/FE/FM and TRX 680 FA/FG, preserving correct clearance and feel.
• OEM Cross‑Reference: Cross‑references to the factory 45117-HP0-A01 piston ensure interface integrity with the caliper bore and seals.
• Premium Materials: Aluminum alloy body with a protective chrome finish resists corrosion in mud, rain, and splashed water common to off‑road use.
• Performance Restoration: Restores smooth piston movement and reliable hydraulic response, returning confident stopping power where it matters.
• Value for Trail & Farm: Affordable rebuild option that extends caliper life without replacing the entire unit, reducing downtime.
• Mechanic‑Friendly Fit: Designed to install with standard caliper seals and without special tools beyond typical brake service gear.

Installation Notes:

• Before installation, thoroughly inspect the caliper bore for scoring or pitting; any damage should be addressed with bore repair or depending on the severity, replacement of the caliper body.
• Clean the bore and piston bore surfaces with brake cleaner and lint‑free wipes to remove rust inhibitors and debris; avoid oil or grease residues that can contaminate the hydraulic system.
• Always replace or reseal with new OEM‑style seals and dust boots when installing a new piston to prevent leaks and sticking; do not reuse old seals.
• When pressing the piston into the caliper, use a proper piston insertion tool or a blunt, non‑marring instrument to avoid scratching the bore or damage to the piston surface.
• Bleed the front brake system after piston installation to remove any air; verify brake lever feel is firm with a full stroke before test riding.
• After installation, verify that the caliper slides freely on its pins and that the pad movement remains consistent through the full travel of the brake lever.

Why Upgrade?

Running a worn or corroded front caliper piston can lead to uneven braking, caliper sticking, and reduced stopping power—especially in muddy or wet conditions common on trails and farms. This replacement restores reliable hydraulic performance and consistent pad contact, helping you stop confidently and avoid brake fade or failure in demanding conditions.