Fluidmaster K-400A-5004 Universal Toilet Fill Valve and 2-In Flapper Repair Kit

Overview

The Fluidmaster K-400A-5004 Universal Toilet Fill Valve and 2 in. Flapper Repair Kit is positioned as a practical, DIY-friendly upgrade for common toilet fill and flush concerns. It combines the trusted Fluidmaster 400A fill valve with the 501 2-in flapper to provide a cohesive replacement pair for many 2" valve toilets. The kit features an adjustable fill valve height, an anti-siphon design, and a solid-flapper mechanism designed to resist twisting. With a 5-year warranty, this kit offers a balanced option for households looking to refresh performance without complex repairs.

Designed to address typical tank issues, this kit aims to smooth out fill cycles and improve flush reliability. It is most compatible with toilets rated at 3.5 GPF or higher, and its universal design helps simplify selection when you’re replacing aging or worn components. Expect a straightforward, tool-light installation process that can fit a variety of tank configurations.

What’s included and how it helps

• Complete replacement set for both fill and flush components, reducing the need for multiple parts
• Universal 2" flush valve compatibility for many residential toilets
• 400A fill valve height adjustable from 9 to 14 inches to match different tank depths
• Solid frame 501 2-in flapper that resists twisting, helping maintain a reliable seal
• Durable construction backed by a 5-year warranty for long-term use
• Easy installation suitable for DIY upgrades with common tools

Key benefits at a glance

• Addresses both fill and flush components in one kit, simplifying repairs
• Adjustable height accommodates a range of tank sizes and depths
• Universal 2" compatibility fits a wide selection of toilets
• Anti-siphon design adds an extra layer of backflow protection in compatible tanks
• Twist-resistant flapper helps maintain a consistent seal over time
• Durable materials and a warranty to support ongoing use
• Installation is designed to be straightforward for many DIY enthusiasts

Real-world use and considerations

Homeowners and renters may notice quieter operation and more predictable flush cycles after upgrading to this kit. It’s a practical choice for replacing aging parts in everyday toilets and for improving overall tank performance on models with 3.5 GPF or higher. Individual results can vary by toilet model, water pressure, and maintenance habits.

Installation tips

Shut off the water, drain the tank, and compare tank height to the adjustable range. Have a wrench or screwdriver handy for securing connections. If your tank uses a 2" flush valve, the universal design should fit, and the anti-siphon feature provides added protection against backflow risks. Always follow local plumbing guidelines and consult a professional if you’re unsure about compatibility with your specific toilet model.