Worth it for contractors who need one kit that fits multiple toilet brands. The 5/16 in. x 3-1/4 in. galvanized steel bolts with double-nut design work on American Standard, Mansfield, Kohler, and TOTO toilets, replacing specific kits like Mansfield 88913 or American Standard 88191. At 4.4 stars across 257 users, some users reported issues with the ‘U’ gasket fit on specific older models, while others praised the double-nut system for preventing leaks.
Skip it if you’re working on one-bolt tanks or wall-mounted toilets. This kit only handles standard 2-bolt residential configurations.
Universal Compatibility Simplifies Inventory
Danco designed this kit to function as a universal replacement for specific brand kits like Mansfield 88913 or American Standard 88191. That matters when you’re stocking a service truck. Instead of carrying four different manufacturer kits, you carry one that handles most residential toilets.
The kit fits both 2-inch and 3-inch flush valve openings. That versatility covers the vast majority of residential toilets you’ll encounter. Montana’s hard water accelerates corrosion on tank bolts, especially in areas with high mineral content. The zinc-plated finish on these galvanized steel bolts provides better corrosion resistance than plain steel hardware.
The real advantage shows up in rural service calls. When you’re 30 miles from the nearest supply house, having a universal kit that works on multiple brands keeps you from making return trips. Contractors appreciate the universal compatibility with any toilet brand, which makes it a versatile choice for repair projects.
Double-Nut Design Prevents Callbacks
The double-nut design provides secure tightening and leak prevention. Here’s why that matters: single-nut designs can work loose over time, especially with temperature cycling. Montana’s freeze-thaw cycles put extra stress on plumbing connections. That second nut acts as a jam nut, locking the first one in place.
Installation follows a specific sequence: Empty the tank, place a rubber washer onto the new bolt and insert it through the hole inside the tank. On the underside of the tank (before placing on the bowl), add a rubber washer, a metal washer, and tighten the first nut to seal the tank hole. Place the sponge rubber spud gasket over the flush valve nut and the U-shaped gasket between the tank and bowl. Set the tank onto the bowl, threading the bolts through the bowl holes. From underneath the bowl, add a metal washer and the second nut to each bolt.
Tighten the nuts evenly until the tank is secure and level. Do not over-tighten to avoid cracking the porcelain. Tighten nuts alternatingly to keep the tank level.
Some users praised the double-nut system for preventing leaks. That’s not marketing fluff. The physics work: two nuts create more thread engagement and resist loosening better than one.
Dual Gasket System Covers More Toilet Types
The kit includes both circular spud gasket and ‘U’-shaped gasket for a superior seal. Many generic kits lack the ‘U’-shaped gasket, providing a more robust seal for certain flush valve types. That U-shaped gasket matters on certain Kohler and American Standard models where the flush valve design benefits from the additional sealing surface.
Included items: 2 Tank-to-bowl bolts (5/16 in. x 3-1/4 in.), 4 Nuts (2 per bolt for double-locking), Rubber washers, Brass/Metal washers, 1 Sponge-rubber spud gasket (circular), 1 ‘U’-shaped rubber gasket. The sponge rubber construction compresses better than standard rubber, creating a more forgiving seal on slightly warped surfaces.
Not every toilet needs both gaskets. But having them means you’re prepared for whatever you find when you open up that tank. Some users reported issues with the ‘U’ gasket fit on specific older models. Fair warning: really old toilets with non-standard flush valve designs might need manufacturer-specific parts.
| Specification | Value |
|---|---|
| Bolt Size | 5/16 in. x 3-1/4 in. |
| Bolt Material | Galvanized Steel / Brass Construction |
| Finish | Zinc-plated / Stainless Steel appearance |
| Gasket Material | Sponge Rubber |
| Compatible Brands | American Standard, Mansfield, Kohler, TOTO, Universal |
| Flush Valve Compatibility | 2-inch and 3-inch openings |
| User Rating | 4.4/5 (257 ratings) |
Who Makes This Work
Professional contractors generally view it as a reliable and convenient solution for replacing worn or leaking tank-to-bowl bolts and gaskets. The kit shines for service plumbers who need reliable parts that work across multiple brands. Property management companies appreciate the universal fit when maintaining buildings with mixed toilet brands.
Warranty coverage follows standard manufacturer limited warranty typically applied to Danco parts. Retailers typically offer 30-day return policies. No lifetime guarantee here, but toilet gaskets are wear items anyway.
For Montana contractors dealing with hard water damage on tank hardware, this kit provides everything needed for a complete bolt and gasket replacement. The double-nut design and dual gaskets address the most common failure points, making it a practical choice for both service trucks and maintenance departments.
Frequently Asked Questions
Q: Will this kit work on a one-piece toilet? A: No. This kit is designed for standard residential toilets with 2-bolt tank configurations. One-piece toilets don’t have removable tanks, so they don’t need tank-to-bowl hardware.
Q: Can I reuse the old bolts and just replace the gaskets? A: Not recommended. The kit includes corrosion-resistant galvanized steel bolts with zinc-plated finish. Old bolts often have corrosion that prevents proper sealing. Replacing everything prevents callbacks.
Q: What’s the difference between the circular and U-shaped gaskets? A: The circular spud gasket seals around the flush valve opening, while the U-shaped gasket provides additional sealing between the tank and bowl. Many generic kits lack the U-shaped gasket, which provides a more robust seal for certain flush valve types.
Q: How tight should I make the nuts? A: Tighten the nuts evenly until the tank is secure and level. Do not over-tighten to avoid cracking the porcelain. Tighten nuts alternatingly to keep the tank level. Snug plus a quarter turn usually does it.
Q: Will this stop a tank that rocks back and forth? A: Usually. The double-nut design provides secure tightening that eliminates most tank movement. If the bowl surface or tank bottom is warped, you might need to shim the tank for stability.
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