Product Overview
The Fluidmaster K-507A-008 Universal 2-Inch Adjustable Toilet Flush Valve Repair Kit is engineered to provide a comprehensive solution for common toilet issues such as leaky tanks and inefficient flushing. This kit offers a universal design that fits most 2-inch flush valve toilets, including popular brands like Kohler and Gerber. It is designed for easy installation, allowing homeowners to restore their toilet's performance without extensive plumbing knowledge.
Key features include:
- Fixes leaky tanks and restores flush performance.
- Easy to install universal design fits 2-inch flush valve toilets.
- Adjustable flush valve height to fit various tank sizes.
- Includes a PerforMAX Water-Saving Toilet Flapper for optimized water use.
- Comes with a universal tank-to-bowl gasket system and a convenient toilet tool.
- Corrosion-resistant flapper for long-lasting durability.
What's Included
Your Fluidmaster K-507A-008 kit contains all necessary components for a complete flush valve replacement:
- Adjustable Toilet Flush Valve
- PerforMAX Water-Saving Toilet Flapper
- Universal Tank-To-Bowl Gasket System (includes various gaskets for different brands)
- Toilet Tool
- Hardware (stainless steel bolts, nuts, washers)

For a visual overview of the kit contents, please refer to the official product video below:
Video 1: Official Fluidmaster Universal 2-Inch Flush Valve Toilet Repair Kit overview and installation guide.
Installation Guide
Follow these steps to install your new Fluidmaster K-507A-008 flush valve. For detailed visual instructions, refer to Video 1 (Official Fluidmaster Installation Guide) at the specified timestamps.
Step 1: Prepare the Tank
- Turn off the water supply to the toilet. (Refer to Video 1, 0:03)
- Flush the toilet to drain the tank.
- Use a sponge or towel to soak up any excess water remaining in the tank. (Refer to Video 1, 0:11)
Step 2: Remove Old Parts
- Disconnect the water supply connector from the bottom of the toilet tank. (Refer to Video 1, 0:13)
- Disconnect the old flapper chain and remove the old flapper. (Refer to Video 1, 0:18)
- Disconnect the refill clip from the overflow tube. (Refer to Video 1, 0:22)
- Loosen and remove the tank-to-bowl bolts and nuts.
- Carefully lift the toilet tank off the bowl and place it on a protected surface. (Refer to Video 1, 0:31)
- Remove the old flush valve and gasket from the tank. (Refer to Video 1, 0:36)
Step 3: Install New Flush Valve
- Remove the cardboard from under the new flapper.
- Remove the gasket, locknut, and friction washer from the new flush valve, keeping them for later installation. (Refer to Video 1, 0:53)
- Insert the new flush valve into the tank hole from the inside. Ensure the overflow tube does not cover any tank bolt holes. If it does, slightly turn the flush valve to clear the bolt hole. (Refer to Video 1, 1:10)
- Adjust the valve height using the integrated tool to ensure the top of the overflow pipe is approximately 1 inch below the tank lever hole. (Refer to Video 1, 1:20)

Step 4: Install Tank-to-Bowl Gasket System
The kit includes different gasket options for various toilet brands. Identify your toilet brand to select the correct gasket:
- All Other Brands: Use the red gasket and the white locknut. (Refer to Video 1, 1:42)
- Gerber® Brands: Use the black gasket system (with arms) and the brown friction washer. (Refer to Video 1, 2:13)
- Kohler® Brands: Use the black gasket system (with arms) and the white locknut. (Refer to Video 1, 3:08)
Once the correct gasket is identified, install it onto the flush valve from the outside of the tank. Use the red wrench provided to tighten the locknut. Go 1/2 turn beyond hand tight. DO NOT OVERTIGHTEN.

Step 5: Secure Tank to Bowl
- Carefully place the toilet tank back onto the bowl, aligning the bolt holes.
- Slide one metal washer onto each bolt, then loosely tighten the hex nuts.
- Alternately hand-tighten hex nuts onto each bolt evenly until the tank is snug and does not rock. DO NOT OVERTIGHTEN. (Refer to Video 1, 3:45)
Step 6: Finishing Steps
- Connect the refill tube to the fill valve and clip it to the overflow tube. Leave roughly 1/2 inch of slack (a small “J” shape) in the chain. (Refer to Video 1, 3:54)
- Reconnect the water supply connector to the bottom of the tank. Hand-tighten only. Do not overtighten, as this may damage the fill valve or coupling nut, potentially causing flooding. (Refer to Video 1, 4:07)
- Turn on the water supply to the toilet. (Refer to Video 1, 4:13)
- Check the water level: The top of the overflow pipe must be a minimum of 1 inch below the tank lever hole. (Refer to Video 1, 4:19)
Operating the Flush Valve
Once installed, the Fluidmaster K-507A-008 operates like a standard toilet flush valve. The PerforMAX flapper is designed to optimize water usage per flush. You can fine-tune the flush volume by adjusting the flapper dial. The higher the number on the dial, the longer the flapper stays open for more water flushed.
Adjusting Flush Efficiency
The flapper dial is pre-set to maximum setting (9). To adjust for most efficient flush, continue to adjust the dial down one setting and flush until the toilet is unable to flush paper properly. Once unable to flush, adjust the dial up one for the final setting. (Refer to Video 1, 4:33)

Maintenance
To ensure the longevity and optimal performance of your Fluidmaster K-507A-008 flush valve, regular maintenance is recommended:
- Periodically inspect the flapper and gasket for any signs of wear, cracking, or deterioration.
- Clean the flush valve and surrounding tank components as needed to prevent mineral buildup, which can affect performance.
- Ensure the flapper chain has the correct amount of slack (approximately 1/2 inch) to prevent it from catching or being too tight, which can lead to leaks.
- The flapper is corrosion-resistant, but regular checks can help identify any issues early.
Troubleshooting
If you encounter issues with your toilet after installing the Fluidmaster K-507A-008 kit, consider the following common problems and solutions:
- Continuous Running Water: Check the flapper for proper seating. Ensure the chain has the correct slack and is not preventing the flapper from closing completely. Also, verify the water level is not too high, causing water to flow into the overflow tube.
- Weak Flush: Adjust the flapper dial to allow more water to be released during the flush cycle. Ensure the fill valve is filling the tank to the appropriate level.
- Leaking from Tank-to-Bowl Connection: Ensure the tank-to-bowl bolts and nuts are tightened evenly and securely (but not overtightened). Verify the correct gasket was used and properly seated.
- Noisy Fill: This kit features quiet fill technology. If noise persists, ensure all connections are secure and the fill valve is properly installed.
For more detailed troubleshooting tips, please refer to the instruction booklet included with your product.
Specifications
| Attribute | Value |
|---|---|
| Material | Silicone Rubber, Stainless Steel, Plastic, Rubber |
| Brand | Fluidmaster |
| Item Dimensions L x W x H | 3.94 x 4.58 x 12.99 inches |
| Exterior Finish | Stainless Steel |
| Inlet Connection Size | 2 Inches |
| Inlet Connection Type | Solvent |
| Outlet Connection Type | Compression |
| Number of Ports | 2 |
| Outlet Connection Size | 2 Inches |
| Specification Met | ISO 9001, WaterSense |
| Valve Type | Flush Valve |
| Item Weight | 1 pounds |
| Country of Origin | USA |
| Item Model Number | K-507A-008-P10 |
| Color | Multicolor |
| Installation Method | Toilet |
| Item Package Quantity | 1 |
Warranty and Support
The Fluidmaster K-507A-008 Universal 2-Inch Adjustable Toilet Flush Valve Repair Kit comes with a 5-Year Limited Warranty. This warranty covers defects in materials and workmanship under normal use and service.
For warranty claims, technical support, or additional product information, please refer to the detailed instructions included in your product packaging or visit the official Fluidmaster website.






