Plumbing Picks is reader-supported. As an Amazon Associate, we earn from qualifying purchases at no extra cost to you.
If your toilet is running, phantom-flushing, or slow to refill, the fill valve and flapper are both likely worn. Instead of buying them separately, a complete tank repair kit replaces every internal component at once for about the same price as one individual part — and ensures everything works together. Here’s what to buy.
| Product | Best For | Price tier |
|---|---|---|
| Fluidmaster 400AKRP10 Complete Repair Kit | Best Overall | Mid |
| Korky 4010PK Complete Kit | Best for Performance | Highest |
| Danco 9D00053525 Complete Kit | Best Budget | Lowest |
Replaced One Part and It’s Still Running?
This is the most common reason people end up rebuilding the whole tank. You replace the flapper, the toilet still runs. You replace the fill valve, it still hisses or cycles on by itself at night. Each part is cheap, but you’ve now made two or three trips to the store and the toilet still isn’t right. The reason is simple: when one tank part has worn out, the others are the same age and usually on their way out too. A brand-new flapper sealing against an old, pitted flush-valve seat will leak no matter how good the flapper is.
That’s the case for a full kit. For about the price of one or two individual parts, you replace the fill valve, flapper, and flush-valve seat together — all fresh, all matched to work as a set. It ends the one-part-at-a-time guessing and gets you a toilet that actually stops running. If you’ve already swapped a part and you’re still chasing the noise, skip straight to a complete kit below.
I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.
Best Overall: Fluidmaster 400AKRP10Editor’s Choice
Check the Fluidmaster 400AKRP10 price on Amazon →
This kit includes the 400A fill valve, a 2-inch flush valve, a PerforMAX flapper, the tank lever and a gasket — every worn part inside the tank, replaced together. The supply line that connects the tank to the wall is not in the box; that is a separate buy, and there is one recommended further down this page. Replace everything at once and your toilet is as good as new. Works with most toilets built in the last 40 years.
- ✅ Replaces fill valve, flush valve, flapper and handle
- ✅ Fluidmaster quality throughout
- ✅ Fits most 2-inch flush valve toilets
- ✅ Every worn tank part in one box
- ❌ Overkill if only one component is bad
- ❌ No supply line included — buy that separately
Rebuilding with individual parts instead of a kit? Read the Korky and Fluidmaster comparison first, so you are not pairing a flapper from one brand with a fill valve that fights it.
How to Do a Full Tank Rebuild
- Shut off supply valve, flush to drain, sponge remaining water.
- Disconnect supply line from tank bottom.
- Remove old fill valve (unscrew locknut underneath tank).
- Unhook old flapper from flush valve pegs and disconnect chain.
- Install new fill valve, reconnect supply line.
- Install new flapper, connect chain with 1/2″ slack.
- Replace handle if included.
- Turn water on, adjust fill level, test flush.
Tip: A full rebuild takes 20 minutes and costs the same as a single service call to diagnose the problem. Do it all at once.
FAQ
How do I know if my fill valve or flapper is the problem?
Put food coloring in the tank. If it appears in the bowl without flushing — flapper. If the water level keeps rising or hissing persists after the tank fills — fill valve. If you’re not sure, replace both — that is what the full kit is for.
Bottom Line
The Fluidmaster 400AKRP10 is the best toilet repair purchase available. One kit, one trip, completely rebuilt toilet. Do it the first time a component fails rather than replacing parts piecemeal.
A full tank kit is a modest spend. Once you’re on your second kit for the same toilet, you’re maintaining something worth replacing — see our toilet picks.
The part people reuse and regret: the tank is already drained and disconnected, so this is the cheapest moment to replace an aging supply line. Fluidmaster B1T16CS Click-Seal braided connector.
Fix the 12 Most Common Plumbing Problems Yourself — Free Plumber’s Handbook — including the toilet fixes plumbers charge $150+ for
Step-by-step fixes for the 12 most common problems — and exactly when to call a pro. Free and instant, from a licensed plumber. Save hundreds on calls you didn’t need.