I installed a new toilet today, and the instructions say for the mounting bolts “Do not overtighten”.
How the hell do I know if they’re overtightened or not? What qualifies as tight?
I ran into the same problem when I tried installing new shutoff valves for a sink. The instructions made it clear that if I overtightened the fittings on the copper pipes, I could damage the pipes and possibly lead to an expensive repair job to replace the pipes. I installed the valves, cranked them down tight, but could not stop them leaking. I called a plumber, and he just grabbed a wrench and really cranked them down. I could have done that, but I was afraid of making things worse.
So how the hell am I expected to know if I’m tightening things to the danger point or not?
It all depends upon what is being tightened - the material, the type of fixture, etc - there is no “one rule”.
Car parts for example - like lug nuts or mounting bolts - will have specific measurements (tighten to x foot pounds) that you can use a tool (torque wrench) to help you measure.
As a general rule- tighten to hand tight (what you can get without putting muscle into it ) and then add a ‘quarter turn’ more.
Or until you hear it cracking - or you see the metal deforming - then STOP - but its already too late.
For the first time in many years I had to change a tire on my car. I had my son do it; he’d never done it before.
The lug nuts didn’t turn with the lug wrench, even after squirting some WD-40. I told him to gently tap the end of the lug wrench with a hammer while I held its socket in place. That didn’t work. Harder. That didn’t work. I started whacking with the hammer as hard as I could. Finally I got the nuts to turn.
Were the lug nuts too tight?
For any precision stuff, you use a torque wrench. Most of the cheap (but quality) ones are the click type where you set a max torque and then it will disengage once you reach that point.
For toilets and such you want to go hand tight, maybe a little more. You just don’t want to wrench on it with tools as hard as you can. In most cases it’s designed to be forgiving and you don’t have a small window of safety.
It is not evidence of overtightening per se. Road crud and grease builds up, etc.
I once overtightened the bolts holding the toilet tank to the toilet bowl and cracked the tank in two. Much hilarity ensued as the float valve insisted on trying to fill the tank.
With wheel-nuts, the usual problem is that some lazy fitter used a power tool to tighten them. Add in a few years out there on the wheel and they can be very hard to release.
Any time you take your car in for a tyre change, look up the torque and make sure that the fitter does it right. Some of them don’t actually know how to use a torque wrench - a favourite is to make it ‘click’ once, and then again for luck.
I always keep a 3 foot steel tube in the car next to the wheel wrench. You can slide it over the wrench to provide an extension that will give you more leverage. If that doesn’t work, stand on the lever and gently jump up and down.
I think these warnings are not actual instructions, they are historical clues. Somebody designed something inherently prone to stripped threads, bent or cracked parts, et cetera. When the warranty returns started, their reaction was to add this label, hoping people would tighten less and fewer products would be damaged.
They should cut to the chase and say, “We admit it. This design is a bit wrong. Tighten to ___ torque.”
It’s not laziness. No garage has time to fool around with a lug nut wrench. They use air tools to mount tires, which, even when set properly, usually tighten the nuts to a point where they’re difficult to remove with the lug wrench provided with most cars. That’s why a lot of folks buy a 4-way wrench for their cars, which allows more torque to be applied.
In my DIY achievements and travails I’ve found that a much more vexing issue with connections under water main pressure than other things. For toilet mounting as others mentioned, hand tight, and there’s really not much downside if it isn’t quite as tight as it could be without breaking anything.
For lines under water pressure I’ve often had your experience, you tighten up new fittings quite a lot…and they still leak. There isn’t much choice then but to tighten them till they don’t. And if there isn’t a shut off valve upstream of what I’m working on but downstream of the main valve for the house, then I am still more inclined to call a plumber. Fortunately whoever completely redid our 119 yr old house’s plumbing around 40 yrs ago put in a fair number of branch shut offs, and I’ve had plumbers put in more in the 25+yrs we’ve been here, to facilitate DIY’ing it next time. I’m OK if I break something and have to start over every once in a while…as long as that doesn’t mean no water in the house meantime.
On car wheel nuts I do it to spec with torque wrench if I’m changing a tire or switching sets (summer and winter for one of our cars, other has all seasons). Of course like everyone else I find that nuts put on at a garage or even dealer under warranty are often way over torqued, but the automotive world goes on.
Once I bought new tires at a tire shop, and when I went to pick it up the car was missing a lug nut. The reason it was missing it because most of the stud was missing. No one at the shop said a thing. I was pissed off when I spoke with the manager. Look, I understand that wheel studs break, I have broken more than a few myself. But they are so damned easy to change why the hell didn’t you do it? Did you really think that I wasn’t going to notice?
Not that it excuses over torquing lug nuts, but they should be re-torqued after 100 miles to account for some stretching, and there’s not one in ten drivers that are going to do that, so the installers may be figuring a little too tight is better than a lot too loose.
Excellent advice. I’ve had the same one since 1994. I love low tech.
I’ve worked in a garage. It’s laziness. The manager was always on us to get the torque wrench, and I was the only one who ever did. I had several “Good job!” notes in my file, because customers who knew one thing from another had mentioned what a good thing it was that I was getting the torque wrench.
Anyway, as to the directions that say “don’t overtighten,” I Google. You can often find specs online. They’re not printed on the directions, because they change.
However, if you can’t find any, the rule that you handtighten it until it’s work, then one quarter turn more is what I would have said.
For car wheels, I can be more specific. 76 ft-lbs for Toyotas, including trucks. Otherwise, 100 ft-lbs for cars, 120 for trucks. Or for a car with very large tires 15, 16 or 17 dia. and drum brakes, 110 ft-lbs.
Back in the mid-1970’s, when flat tires were a lot more common and blatant sexism wasn’t usually even called that, a friend and I had a flat on a back road and couldn’t get the tire off. I know we jumped on the lug wrench. I think we put a cheater pipe on it and jumped on that. We eventually gave up, got to a phone, and called a service station.
The man who came out took one look at us and said (probably not these exact words, but certainly this exact sense): ‘Hmmph. Girls! Of course you can’t get the lug nuts off!’
It was worth paying to have the car hauled in to someplace with a power wrench in order to be able to laugh at him when he couldn’t get them off either.
And if there isn’t a shut off valve upstream of what I’m working on but downstream of the main valve for the house, then I am still more inclined to call a plumber. Fortunately whoever completely redid our 119 yr old house’s plumbing around 40 yrs ago put in a fair number of branch shut offs, and I’ve had plumbers put in more in the 25+yrs we’ve been here, to facilitate DIY’ing it next time. I’m OK if I break something and have to start over every once in a while…as long as that doesn’t mean no water in the house meantime.