Rusty toilet tank bolts

last year

last modified: last year

I needed to replace the bolts because the tank was leaking. I can't get one of them off.

When I turn the nut, the bolt just turns with it. The head is so rusted that a screwdriver blade won't stay in the slot, and a vise grip won't stay put if clamped on the sides (when I can clamp them at all).

I've seen all sorts of suggestions: propane torch, $350 induction heater, WD-40, angle grinder, nut splitter... In my experience, heat and substances like WD-40 have no effect on bolts with this degree of rust. The nut splitter sounds like the most promising idea, but I can't find one that's small enough to fit. The smallest size is for bolts 9-12 mm diameter; a toiler tank bolt is 5/16", just a bit under 8 mm.

Any new ideas, or comments on the ones I mentioned?

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Comments (8)

klem1
last year
Yea that sounds frustrating. I would go ahead and remove ballcock to give more room to work. Tank to bowl bolts are supposed to be brass for this very reason.

Grab tip of bolt with vice grips and nut with another to see if nut can be backed off enough to grasp bolt head inside tank. Hopfully you can snap bolt. If nut starts moving you have 2 choices. #1 saw tip of bolt with destroyed threads off smoot and remove nut. #2 Get between nut and tank to hacksaw bolt intwo If those fail, try drilling it out.

Be sure to start dead center with a small drill bit and work your way up until head separates from bolt stem.
central_valley
Original Author
last year
The drilling idea sounds like a good one that I haven't considered. I'll try that next.

Right now I'm trying to cut the bolt with a hacksaw between the toilet and the tank. The first bolt came out (head broke off when I tried to turn it), so I can move the tank enough to get the blade in. But I can't see in there, so I can't tell whether I'm making any progress.

Already tried the vice grip, that didn't work. The head is so rusted that I can't get a grip on it.

I thought "these ought to be made of brass," but I looked on Amazon and at my local home improvement emporium, and I couldn't find any that were. We live in sad decadent times.
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millworkman
last year
Amazon Link to many Brass Toilet Tank Bolts.
Jake The Wonderdog
last year
last modified: last year
You use a bare hacksaw blade in a holder to cut the bolt. These are available at any hardware store for a few bucks. There is always enough play in the connection that you can tilt the tank a bit to get the blade in between the nut and the washer on the outside of the toilet. It's pretty quick, the bolts are brass or mild steel and not very thick. Same trick for toilet mounting bolts.

if you happen to have a oscillating tool with a metal cutting blade, that works even faster.

The apartment buildings I took care of had 300 toilets - Hacksaws were in every "toilet kit" - along with replacement bolts. Today there would be an oscillating tool in every kit.
klem1
last year
Steel toilet bolts are only one of countless traps consumers fall for when comparing prices. Since you are able to reach it with hacksaw,that should do the trick. Be aware that tank might topple at the moment bolts is no longer holding it.
central_valley
Original Author
last year
@Jake The Wonderdog Thanks, I'm familiar with the hacksaw blade holder, but I don't need it. There's enough room to get a regular hacksaw in there.

I don't have an oscillating saw (what I know as a Sawzall). I could get one, but their blades are thicker than hacksaw blades, and I'm afraid it would damage the toilet.

I did discover a long-unused device that resembles a Dremel tool, with a complement of 3½" grinding disks. If I get tired of the hacksaw I'll see what that will do to the bolt head.
Jake The Wonderdog
last year
Hmmm, cutting those bolts is about a 10 minute job with a bare blade. The hardest part is getting your body in an awkward space.

Not a Sawzall - but the tool I posted. Blades are about the same thickness.
klem1
last year
I hesitated to say this for fear it might sound harsh but the bolt can rotate back and forth with teeth on blade without actually removing metal. Clamp your vise grips to prevent bolt rotating while you manipulate saw.