Does clicking a torque wrench more than once add torque each time.

WOW, in true TW fashion this has been extremely overthought and discussed to death.

Dont overthink it. A cheap click type torque wrench is fine for most tasks. The $20 harbor freight type has been extremely well received.

If you are working below 50ft lbs then you need a nicer wrench then $20. but that 50-150ft/lbs range is fine for most cheap wrenches.

 

For practical applications where a click-type torque wrench is acceptable to begin with ( ) the torque doesn't increase with subsequent clicks. The preload in the internal spring is overcome at the same torque each time. Remember torque wrenches have tolerances. A 50-250 ft/lb wrench with +/-4% accuracy means it can be off by +/- 10 ft-lbs. Some poorly-designed torque wrenches with high internal friction don't click if you go at it slowly. I snapped a wheel stud before I learned this. So be sure to click 3 times with the same gusto.

The FSM torque is 83 ft-lbs, so by going to 86, you're already overtorquing it by 4% on top of other sources of error.

By the way, some 4Runner manuals says to use 83 ft-lbs on steel wheels and 74 ft-lbs on alloy wheels, which doesn't make sense to me. I've also seen Toyota-branded wheel locks say 74 ft-lbs.

For trail repairs I give my lugnuts two ugga-duggas with my M12 stubby impact on setting "3". One time I subsequently drove 1100 miles and went wheeling on the mismatched spare, and didn't have a snapped stud or loosened lugnut

 

I have read this several times. Is there a formula or guide that predicts the change in the torque setting when using anti-seize?
What are the differences in the gray and the copper anti-seize? Does one work better than the other in certain applications?

 

I have a “significant difference” type question that comes from the comment earlier about 4% error in some torque wrenches. Every wrench obviously has some error. If a spec calls for, say, 83 ft-lbs. that implies plus or minus half a pound as written. Or is 83 an overly precise conversion from a rounder metric number. In short, how exact do torqued fasteners need to be? Obviously we want to be as precise as we can. But is the range 10%? Plus or minus 30%?

 

As was said it comes down to the manufacture of the wrench.

The only bolts I torque are on the Engine. I doubt I have used it in 15 years.

Then everything gets never seize in my case.

If your worried you can get your Torque Wrench Calibrated and Certified with paper work

 

I went through a triple torque phase and it was so bad that I had to do “jazz hands” after to put my fear to rest.

probably 3 years of this, every day 4-7 vehicles.

wasn’t ocd but an isolated similar symptom

Still if someone talks to me while talking I start over.

It’s an honest thing and if the 3 clicks make you feel secure I’d keep doing it.

 

Apparently you don't have to spend a lot to get a relatively accurate torque wrench, and they can take quite a bit of abuse. I've had my cheap 1/2" wrench for years and don't worry about its accuracy too much. Seems like +/- 4% is the standard, so I would guess that torque specs provided take this into account.

The spec provided for axle u-bolts on Tacomas was like 27 or 37 ft pounds or something, ridiculously low. I'm not sure they corrected it in later FSMs, but I bumped mine up to 72 on my last 2 Tacomas. But, most people don't and I didn't on my first, and I haven't heard of axles coming loose. So, how important the accuracy is seems to depend.

I always click more than once. It's like clicking tongs three times before using.

Anyway, here's a video:

 

1. The metric number isn't really round:



2. The intent of torquing is to achieve tension in the bolt or stud. The conversion between rotating torque and linear tension has a lot of variability caused by friction in the threads. With new, dry threads, there could be +/-20% variation between torque and linear tension. The FSM torque value makes an assumption of friction for dry threads. If there's rust, contaminants, or lubricant on the threads, the actual linear tension will change even when the torque applied is constant. For common applications, engineers usually aim for 80% of the stud's yield strength. Whether Toyota's engineers did that for wheel studs is unknown.

For critical applications (like building F1 race engines), where both ends of a bolt is accessible, it's more precise to use a dial indicator to measure bolt stretch (e.g. tighten bolt until it stretches 0.002 in.). This cuts through all the aforementioned variability. You'd have to number individual bolts and record their original- and tightened lengths on a data sheet. When disassembling the part, you'd measure the bolts again and throw out ones that have had permanent stretch. Example of a stretch gauge:

$181 ARP 100-9942 Billet Rod Bolt Stretch Gauge

https://www.amazon.com/ARP-100-9942-Billet-Stretch-Gauge/dp/B001T6F78Y/

Meanwhile, they rattlegun the axle nut when changing wheels during pit stops, so don't overthink it

 

The "this is being over-discussed" thought comes to mind often when I'm on TW, I get it. I have to remind myself though, that's kinda the point of a forum and when someone makes a thread like this, it's usually because they want all the detail/help they can get on the subject. If my comments don't add to the discussion, or even answer the OP's question, I try to keep them to myself. Of course that's just me, and sometimes it can't be helped. Don't deflate the thread or other commenters for throwing in their two cents though.

OP, as long as you're backing off the wrench after it clicks, a properly functioning torque wrench should not add torque with subsequent clicks. That is, as long as adjacent fasteners on the same piece are not torqued afterwards. On wheel lugs specifically, it is common for some lugs to turn a little further on a second pass, but that's technically not increasing the torque on the lug so much as re-torqueing it.

 

I double check with a second click in a star pattern. Just don't keep going after the click of the set torque.. will add more torque and screw up the calibration of the wrench.

 

Back in the day I would torque in the recommended pattern, then QC guy would repeat to verify torque.

But that was nuclear plant work, for my vehicle wheels I would snug up by feel, this worked for many years with never an issue of stretched studs or loose wheels. Same for spark plugs I can feel the washer crush then snug.

Life doesn’t have to be that hard lol.

I have multiple torque wrenches that I would use on critical parts of my truck now if I’m not experienced with torquing by feel.

 

Here's my theory, and I'm sticking to it.

Let's say you have a clicker that is ABSOLUTELY accurate. It clicks dead on at the proper torque.

As you are putting pressure on the wrench, anticipating the click, when it actually does click there is some residual pressure being applied on the handle because we're human, there's a slight delay between when the wrench clicks and when we stop applying pressure (by the way, women have a faster reaction time than men).

This generally results in a slight, but insignificant overtorque in reality.

So now imagine that being repeated multiple times. Each time, because we're human, slightly more pressure is applied after the wrench clicks.

So in theory (mine), multiple clicking likely results in more overtorque.

That being said, I think the end amount is so small that I can't imaging a situation where it would matter.

 

You click once.
If you want to make yourself look stupid in front of other people then click more than once.

Lugnuts are not precision components. Internal engine fasteners are.

very few fasteners have enough give in them or the metal they’re on to change tightness over time. Rear leaf U bolts are one of them.
You can re check tightness later on. 99% of the time never do. Never had a problem.

costco tire center recommends bringing the car back after 100 miles post new tire install. Probably wasted labor money for liability reasons to cover their ass. To give the staff an opportunity to “check” the first guy did his job right and didn’t leave a lug off. And to put liability on the customer if they fail to bring the car back at that time per guidelines; which I’m guessing most people would realize it to be a waste of time and not come back.

more professional shops do not say come back for a re torque. But Costco tire center is not professional, it is amateur, which explains this.

 

Man this thread has the potential to be just as good as an oil thread lol

Just from my schooling/engineering experience, I'd have to agree with this idea. If I were to split hairs, I'd say there's quite a few variables that might affect the "as-torqued" final value such as position of bolt, thread mating surface friction, prior calibration of wrench, how "hard" you click it, etc.

I'd also argue clicking it 3x gives you 3x the chance of torquing it slightly past the value you're shooting for.

With all that said, I don't think it matters much, as long as you aren't going crazy with it. Personally I always torque the bolt at something lower than the value I'm shooting for so I know the wrench is "clicking" properly before I torque to the final value.

 

I just got done checking torques after having the lift for 6 months. There were a few bolts (rear bottom leaf hanger bolts and u-bolts) took a bit more torque. Also, by getting in there i discovered the bottom coilover bushings got installed backwards by the installer... good to check around once in a while lol. Any time you recheck a torque unless you loosen the bolt before hand aren't you basically clicking more than once? Most shops (and installation instructions) say to check torques after a certain amount of miles. Things can get loose and some bolts are designed to stretch like u bolts.

 

instructions say check twice for liability. Depends on the fastener. Good fasteners don’t loosen. Bad ones do.

it’s wise to check if you install solid off road motor and trans mounts. Not only are they in one of the highest load and vibration spots of the truck, they are tightened against paint and powder coat which will squish as opposed to metal on metal

Torque wrenching is done in a consistent smooth slow motion.
If something is torqued 70 ft lbs, you can click it 1,000 times if it makes you feel good to waste time and beat on the tool. Doing that isn’t going to further tighten it to 90 ft lbs

some things have safety wire or cotter pins
You can put tamper proof paint marker to see if it moves

or loctite to keep it put. Red loctite is harder to remove. They came out with orange loctite to be a hybrid of the two

 

Good advice. I agree that the 2 pass method, 1st at a lower value, second at the final value is good practice, especially if you’re going to torque wheels (star pattern).
In fact the multipass method from lower to final torque is what we do for some applications in power plants.
https://www.moderntiredealer.com/articles/25811-custom-wheel-torquing-101

I may start a technical oil discussion thread one day. For those hoping.

 

It's a complex interaction that depends heavily on the fastener materials, thread pitch/inclination, fastener size, temperature, lubricant properties, etc., and I imagine the relationship is non-linear. Because of this, while there are some analytical formulas that can reasonably approximate the behavior of fasteners, it's not something you can just plug-n-chug as you need experimental data for a given system to fully describe the relationship. There could potentially be data out there on the internet describing this particular situation (i.e. M12 x 12.5 fastener, correct materials, etc.) out there somewhere, but I haven't found it. That being said, this might be a good place to start to get a general idea of what's going on: https://www.hextechnology.com/articles/bolt-lubricant-torque/

As a VERY rough rule of thumb, I'd say that somewhere in the range of ~75-85% of the input torque to achieve the same clamping force/internal fastener stress—but I have to stress that this is a very rough estimate.

It might be worth noting that anti-seize that contains copper might induce galvanic corrosion if the anti-seize is low quality or degrades over time (e.g. due to water ingress or salt wash). That being said, galvanic corrosion isn't typically an issue for automotive applications. I think in general, the grey stuff will work just fine, although when you say "grey" that could really mean anything—I use Loctite LB8203 on my truck for certain fasteners (although not on the lug studs/lug nuts).

 

The reason they say to come back after 50/100/et.c miles is due to liability, but the reason they are worried about liability is that fasteners can loosen over time. When subject to different moisture levels, temperatures, vibration and stress from driving, metal fatigue, etc. It's not as simple as the metal having some "give", you have to consider the system as a whole and the environment it operates in. If the material does "give", which can happen, that means something has likely deformed plastically and unless it's a TTY fastener, plastic deformation can mean a failed component.

WRT lugnuts versus internal engine fasteners being or not being "precision" components—honestly, I would expect both of those types of fasteners to be spec'd by very similar standards (e.g. ANSI, ISO, MS) with very little difference in their "precision".

In practice, I would agree that it's good practice to re-check your lugs after some drive time. In fact, it's good practice in general to re-check fastener torque after a shakedown or some drive time.