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Tightening bolts on the base of a toilet is the one thing about toilet installation that has me the most nervous. They say not to over-tighten, but how tight is too tight before the porcelain is subject to cracking? Do I tighten until I can't tighten anymore? Do I tighten it just before I think it's at its tightest?

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If the porcelain cracked, it was too tight! – Matt Jul 8 '13 at 0:18
How many licks? Well, let's see. One, two... – Mazura May 21 at 0:35
Last one I installed used the guideline of "tighten fully by hand, then use the wrench to give it one quarter turn more." Check what your unit's manufacturer suggests. – keshlam May 21 at 0:59
up vote 15 down vote accepted

I start by hand tightening as much as I can, then I tighten a little on each side and check if the toilet moves. If it does then I tighten a bit more, check and repeat until there's no movement. You're trying to avoid bowl movement, so that it doesn't shift or fall over, not to hold the floor up by the toilet bolts.

As tight as you can go will probably snap the porcelain (with a good socket you can torque a nut onto a bolt quite a bit). Until you think it's about to snap is just guessing.

Snug. No movement. Enjoy.

"Too tight" is a sixteenth of a turn past where the porcelain snaps :-)

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The length of your wrench will affect the "feel" of tightness. I have a ratchet with a 2" handle (the most expensive wrench in my toolbox) that I use whenever I don't want to over-tighten a nut (and don't have an explicit torque setting). – kdgregory Oct 15 '11 at 23:11
Good answer. I basically tightened the nuts to the point where the toilet was level and did not move at all. One last question, though: When I lay my level across the bowl and apply upward pressure on either side of the bowl, the level indicates that there is very slight movement because the bubble moves a tad to the left and right (still within level parameters). However, I can't feel the movement myself. Does this seem fine? – oscilatingcretin Oct 16 '11 at 17:36
@oscilatingcretin I would personally be ok with it, since the normal operating conditions will have pressure in the downward position, but then I'm more paranoid of over tightening than falling off. – Stephen Oct 17 '11 at 3:08
Exactly - the point of the bolts is to hold the toilet in place, NOT to create the seal. The seal is created by the wax ring. One quarter turn too far on that bolt and you've ruined a multi hundred dollar toilet. If it doesn't move when you sit on it, it's tight enough! – The Evil Greebo Sep 27 '12 at 10:24
I almost sprayed coffee on my screen when I read "You're trying to avoid bowl movement". :) – aphoria Sep 27 '12 at 12:40

One thing that will help prevent the porcelain cracking is to use a rubber or plastic washer between the head of the bolt and the bowl.

This will take some of the "excess" force by deforming slightly, and by checking for the washer deforming as you tighten you'll have an extra visual check that you've applied enough force.

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Yeap, not only will it take excess force, it will provide good hold of the toilet so that it doesn't swing. – sharptooth Sep 27 '12 at 10:09

My grandfather was a master plumber for more than 50 years. I asked him one time how tight to make a sink faucet shutoff valve connection. His answer is a classic ... "Tight enough so it don't leak". There is a lot of wisdom in this. The answer for the toilet is the same thing, not too tight but tight enough.

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Whatever length wrench you're using, choke up on the handle all the way.

"Too tight" begins once you start deforming the washer.

Once you do start to deform the washer, you have to toss the, "hand tighten, then 1/4 turn with a wrench," out the window (not that I've ever found that sentiment to be satisfactory). I've never cracked a toilet by over tightening its bolts. The washers that come with a bolt kit are intentionally flimsy.

If there's a word for the day, it's : snug (for which you either need years of experience, or one cracked toilet, to know when to say when).

My preferred finishing touch is, once it's sung, grout it in place (keeps hair from getting stuck in the grove, and other yuckiness) and then I guarantee, it will not rock. My preferred tool, is my little six inch adjustable wrench. I don't choke up on it, but I know when to say when.

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