Hole in tank too small for 5/16" bolt

[marcusd]

I'm looking for a smaller diameter brass bolt for the bowl-to-tank connection. One hole accepts the new 5/16" bolt just fine, but the other hole is too small. The old hardware is smaller diameter but its really corroded and I would like to replace it.

I can't seem to find a bolt with a large enough flat head on it to get a good seal with the rubber washer. I've tried using a stainless washer on top of the rubber washer but water get in between the bolt head and the steel washer. I could use another rubber washer in that joint, or maybe JB weld the steel interface.... Well you see where this is going.

Any advice where I can get the right size bolt?

[jadnashua]

They come in 1/4" too, if that helps.

[Herk]

American Standard uses flimsy little bolts if you can find some.

[toolaholic]

Use a stainless washer over the leaky new one

[Bob NH]

You can probably enlarge the hole slightly with a Dremel tool and a silicon carbide or diamond grinding bit. Use a bit that is too small to fill the hole so you can't wedge it in.

[Lakee911]

Any chance the hole has calcium or mineral deposits around it making it smaller? I'd try a small file or something to clean it.

[Redwood]

No its a Central Am. Std. Toilet that came with those cheesy 1/4" zinc plated steel bolts....
Hecho en Guatamala we have outsourced toilet manufacturing to a contry where most of the population doesn't have one!

[Mikey]

Any decent hardware store will carry 1/4" brass round-head screws and nuts to match, SS washers, etc.