# TLDR Review: Fluidmaster K-400H-039 Toilet Fill Valve and Flapper Kit

*Published: 2026-01-09 | Updated: 2026-01-09 | Source: https://shopsavvy.com/reviews-tldr/fluidmaster-k-400h-039-toilet-fill-valve-and-flapper-kit*

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## Product: Fluidmaster K-400H-039 Toilet Fill Valve and Flapper Kit
**Brand:** Fluidmaster

## Pros
- Easy and quick installation with clear, easy-to-follow instructions suitable even for beginners and DIY enthusiasts
- Adjustable 2-inch flapper allows for fine-tuning flush performance and water flow
- Provides a stronger, more effective flush with reliable positive shut-off to prevent running water waste
- Quiet operation with smooth fill valve performance, eliminating annoying running noises
- Comes as a complete kit including all necessary parts for a full toilet repair or upgrade
- Reliable sealing that effectively stops leaks and running toilet issues
- Compatible with braided supply lines for increased installation stability
- Suitable for multiple uses with consistent quality reported across several purchases
- Valve height and flow adjustments are straightforward and user-friendly

## Cons
- The connecting tube is shorter than some previous models and may interfere with the flush lever, sometimes requiring a replacement tube
- The adjustable valve can occasionally leak a tiny stream of water at certain settings, though it usually does not cause significant problems
- Slightly slower refilling speed compared to older models
- Build quality is decent for the price but not expected to last for decades; some users may want a longer-term solution

## Bottom Line

If you're looking for a straightforward toilet fill valve and flapper kit that’s easy to install and effectively solves running toilet problems while improving flush strength, the Fluidmaster K-400H-039 is a reliable choice. Just be sure to measure your flush valve opening beforehand and be aware the included tube might need swapping if it interferes with your toilet’s flush lever. For those who want a super long-lasting solution or faster refill speeds, consider evaluating other premium models, but for solid value and performance, this kit hits the mark.

## Pros vs Cons at a Glance

| Pros | Cons |
|------|------|
| Easy and quick installation with clear, easy-to-follow instructions suitable even for beginners and DIY enthusiasts | The connecting tube is shorter than some previous models and may interfere with the flush lever, sometimes requiring a replacement tube |
| Adjustable 2-inch flapper allows for fine-tuning flush performance and water flow | The adjustable valve can occasionally leak a tiny stream of water at certain settings, though it usually does not cause significant problems |
| Provides a stronger, more effective flush with reliable positive shut-off to prevent running water waste | Slightly slower refilling speed compared to older models |
| Quiet operation with smooth fill valve performance, eliminating annoying running noises | Build quality is decent for the price but not expected to last for decades; some users may want a longer-term solution |
| Comes as a complete kit including all necessary parts for a full toilet repair or upgrade |  |
| Reliable sealing that effectively stops leaks and running toilet issues |  |
| Compatible with braided supply lines for increased installation stability |  |
| Suitable for multiple uses with consistent quality reported across several purchases |  |
| Valve height and flow adjustments are straightforward and user-friendly |  |

## Current Prices

| Retailer | Price | Availability |
|----------|-------|-------------|
| My Store | $9.50  | Check |
| Ideal True Value Home Center | $15.18  | Check |
| Shell Lumber and Hardware | $15.73  | Check |
| SupremeDIY.com | $15.78  | Check |
| BuilderDepot | $15.98  | Check |
| Hardware & Moreee | $15.98  | Check |
| Max Warehouse | $15.98  | Check |
| MID Hardware | $15.98  | Check |
| SupplyHog | $15.98  | Check |
| The Home Depot | $16.96  | Check |
| Amazon | $16.98  | Check |
| Walmart | $16.98  | Check |
| HardwareAndTools.com | $17.19  | Check |
| Store Seven | $17.47  | Check |
| Lowes | $17.48  | Check |
| SIM Supply | $17.65  | Check |
| The Lumberyard | $17.65  | Check |
| UpStart Auto Parts | $17.99  | Check |
| Valu Home Centers | $17.99  | Check |
| Do it Best | $18.49  | Check |

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*About this review: We pulled together findings from professional and user reviews, and cross-referenced them with ShopSavvy's pricing data from thousands of retailers to give you the short version.*