Removing rusted screw and wingnuts from toilet tank

Question

My toilet tank is held in place by two screws, which have rusted so much that the shape in their head is almost completely disappeared. On the opposite side, they are held in place by two wingnuts made from plastic. I tried to losen one of them with pliers, but that only ended up in one wing breaking off.

Main question is: what is the best way to get it off, given the wingnuts?

I'm aware of this other question, and this is the answer I like most, which suggest using a mechnaic's nut cracker, but I have a few follow-up questions to that:

• Is there a way to remove the bolts without cutting/drilling/breaking them? (Not that I need them, I'm just afraid of damaging the tank or the bowl in the process.) E.g., I read somewhere else that WD-40 might be enough, but did anyone actually try this with success? Also, where would I put it: between the wingnuts and the toilet bowl? Or below the head of the bolt? (It would be quite difficult to get into both places...) Or maybe with some rust-solvent?

• Can the wingnuts also be broken by the mechanic's nut cracker? (Obviously, plastic would be easier to break than metal, but the shape might not make it easy to access.)

• Also, as far as I see, this is a tool mostly for car shops (as the name suggests), so I guess a plumber would use some other tool. Which one would it be?

The two rusty bolts inside the tank:

A wingnut:

EDIT: Proper name for wingnuts.

UPDATE: Thanks everyone for the input. Yesterday I was able to remove one wingnut by gripping it really hard with pliers adjustable sized wrench. However, the screw itself is stuck, together with one gasket on the top, and one on the bottom.

The other one moved too a few turns, but it came to the point that now it is rotating together with the screw (and I could not find a way to stop the screw, because the head is so rusted).

Answer 1

When I had the same problem, I took a 4 1/2 inch angle grinder to the bolt heads. Just be careful and try not to touch the grinder to the porcelain. Also dont grind so long that you heat up the bolts to much and be careful not to melt any plastic bits in the toilet with the grinder spray. When you are done grinding, make sure you clean out all the slag and dirt that you generate. If you only grind inside the tank, you dont have to worry if you slip a little, any marks you make will be hidden when you close the tank lid!

Answer 2

It's called a wingnut. I see the rust on the bolt heads in the tank. Are they also rusted under the wingnuts? Those wingnuts should be replaceable at your local home center. Have you checked? If so, try some WD40 or other penetrating oil under the wingnut and let it sit for a few minutes and then try turning them with large pliers or vise grips putting equal pressure on both wings. If they break off just replace them.
The bolts and gaskets under them should also be available for purchase.

Answer 3

The plastic nuts put you in a better position than you might otherwise be, I think.

While a nut cracker would be difficult to apply to a wingnut, much less under a toilet tank, a pair of locking pliers or similar "high force" tool should be able to break (crush) the plastic nut so you can get the rusted bolts out.

Example, not endorsement:

Answer 4

Based on the updated info about the screws and bolts being tightly rusted together, I'd suggest 2 things:

1. A heavy dose of a rust remover
   • I've had good success with PB Blaster™ in the past, but any similar product should work.
   • Give it a good several hours (or even over night) to soak in and do its job.
   • Put a disposable bowl under each nut to catch drips - you don't want it ruining the flooring.
   • See if you can loosen it by grasping the screw head with one pair of locking pliers and the nut with another pair.
2. If that doesn't loosen things up, I'd suggest the use of a hacksaw on the nut under the bottom of the tank/bowl.
   • Cut as close to the top of the nut as you possibly can. You should be able to get most, if not all, of the nut cut off the bolt. If you can't get it all cut off, once you're down to a thin layer of nut remaining, you should be able to break the rest of the rusty bits off.
   • A hand-tool is less likely to cause damage to the porcelain coating because you're moving much slower than a power tool would and you'll notice very quickly if you are starting to cause damage. You'll have the opportunity to stop and adjust at the lightest of scratches whereas a power tool will do notable damage before you have a chance to react.
3. Instead of sawing, use the nut cracker from the question linked in the OP.
   • If there is still concern about breaking the bowl/tank, hack sawing through part of the bolt (option 2) will leave much less material to be broken by the nut cracker, making its job easier.

Answer 5

Thanks for all the suggestions.

It turned out that under the wingnuts there were also hex-nuts holding the bolts in place. I added some WD40 on the top of the bolts, and after one day, the right bolt came off quite easily (with a wrench and a screw driver).

          _____           <--- bolt head
      <===========>       <--- hard plastic gasket
      -------------       <--- rubber gasket
        ========          <--- hole in the tank
       <=========>        <--- hard plastic gasket
          ===             <--- hexnut (stuck)
           |
           |
           |
         <--->            <--- wingnut (stuck)
           |

However, the left bolt was stuck and corroded together with the hex-nut (even the wingnut got stuck) and even the slot on the top of the bolt was almost totally eroded (so I could not use a screw driver, I was trying to hold it with pliers). So in the end I cut the top solid plastic gasket with a knife and pulled off the rubber gasket below it. My original plan was to have a better grip on the head, with the pliers in this way, but suddenly the bolt just fell through the hole (which was much bigger than its head).

TL;DR: I cut off the top plastic gasket and removed the rubber gasket on top, and at that point the bolt was free.