how to estimate torque if a torque wrench doesn't fit

[toolaholic]

Hi, Several times I needed to estimate torque cause torque wrench did not physically fit. My back shocks on my dakota R/T needed torqued top and bottom to 75lbft. The upper passenger side nut was hard to access due to exhaust pipe sheild. I used a craftsman 13x15(15 used)mm double box and just pulled hard to torque. Not worried should be fine. The next instance was the rear pivot shaft nuts on the upper control arms could not be acessed w/ torque wrench. Torqued the front nuts to factory spec 130lbft then torqued the rears w/ a craftsman 22x24mm(24 used) double box.Later even used a slightly longer proto 22 x24mm double box. Not overly worried as I counted threads exposed on rear bolt and matched to front. The doosie is the pivot shaft to frame nuts are 155lbft. On the front passenger side the exhuast manifold is in the way. A hazet very deep offset 22 x20(22 used)was used to remove and install upper control arm. How close can you get to 155lbft w/ a deep offset box wrench that's just shy of 12" long.? The rear passenger side nut was torqued to 155lbft.This worrys me.I even krano oiled the threads and pulled w/ all my might on front nut w/ the hazet deep offset.. So far nothing has come loose. Very few miles on truck because after suspension work,water pump leaked. So truck was down for water pump and I did plenum pan on intake. Truck has gone on one 50 and one 100 mile trip. Should I perioically check these nuts? Any tips on torqueing w/o the torque wrench.

 

[Rookie2]

tighten till they creek ! practice on a bolt that you just torqued. get a feel for what it takes to just move the nut or bolt. in a pinch i hook two combination wrenches together .

 

[NHBandit]

I guess I'm one of those old school guys who think having torque specs for every little thing is overkill. Critical engine stuff like head bolts, connecting rods bolts, sure. Lug nuts, yeah them too but things like shock bolts ? WTF... A little common sense is all I've ever used.

 

[redwrench60]

Just use the German method, torque everything........good-n-tite.

 

[ihateminimumwage]

I guess I'm one of those old school guys who think having torque specs for every little thing is overkill. Critical engine stuff like head bolts, connecting rods bolts, sure. Lug nuts, yeah them too but things like shock bolts ? WTF... A little common sense is all I've ever used.

For home use (not including critical engine parts), that's the way I am. In the shop working on other people's expensive equipment, everything gets torqued to spec. Not letting anything get out the door without double checking every nut and bolt.

For the OP, if you're at all concerned about something coming loose, just paint pen a line from the nut/bolt head to the surface. If it tries to come loose, you'll know with just a glance.

 

[Chuck122]

Look at the specs and test it with a torque wrench stick in a vice. Sometimes it will tell you if they spec it because it needs to be "at least this tight" or if it is more of a "no tighter than this" kind of deal. Cause sometimes Tonga need to be just snug and other it needs to be raped-ape tight

 

[Airframer]

Torque till it strips then back off a quarter turn.

No, seriously, if you are determined to get things torqued to spec, there will be a tool that can do it. You just have to find something that fits.

 

[AV tinker er]

Turn it till you hear a "pop" then back off a 1/4 turn.

 

[MG44]

just use your feel. Generally nothing outside of the internal engine & transmission are going to be super critical to torque. Control arms? Tighten them. Ball Joint stud that only an open end wrench fits on? Tighten it. LIFE WILL MOVE ON!

 

[RCStocker]

I have been putting shocks on cars for over 55 years. I have never torqued one of them. I guess it is form growing up around a machine shop and having served a tool and die apprentiship in my former life. I learned where to stop tightning I have stripped a few bolts in my day. I am not a little person.

I was working in my dads frinends machine shop in my highschool years. We were putting a huge transmission die together. It was the mold for the housing. I had a 3/4" bolt that would not go in. The allen wrench was huge and I still have it. I went and told the forman it would not go in. I had backed it out 3 time. Blew out the hole an checked the depth of the blind hole and the length of the bolt that I was given to put in. All were clean and ok. The forman comes out and to see what the problme was. He picked up a pipe and told me to use it. I toled him in the office I was going to twist and break the allen head bolt. He said you can't break that. I smiled and said yes I can. He was a nice man and in charge. I would have not done it but he said to go aheat. This mold was so large that I was sitting on top of it and I did not cover 20% of it. I braced my left leg aginst the part of the mold where I could get a footing and putlled on the pipe. I repeated that I was going to twist the bolt off. Again I was told to pull. I did not pull all that hard and the bolt broke off. They had to send it out and have it burned out. LOL I was pissed. 1/4 of a turn after it is tight is all it needs. I only break cheap import bolts these days.

I guess if you break or strip a bolt you will know you did it worng. LOL

 

[driver]

I heard a number of years ago that the average guy can pull about 100 lbs ft. It has served me well.

 

[rockwithjason]

i have used crows foot wrenched and extensions to get into tight spaces like that.

 

[toolaholic]

i have used crows foot wrenched and extensions to get into tight spaces like that.

Thanks I have crows feet. Never thought of them. I needed a exrra deep offset like the hazet to clear the control arm lip.

 

[toolaholic]

Thanks for all the replies. I even torqued my daughter's lumina dogbones to 30lb ft after changing plugs. I am a relative newbie at car repair and until I develope a feel for torque;I feel secure using a torque wrench cause I know it's done right not too loose or tight.

 

[Richard D]

i have used crows foot wrenched and extensions to get into tight spaces like that.

That will nullify the torque reading. Not that shock bolts need them anyway.

 

[redline380]

I heard a number of years ago that the average guy can pull about 100 lbs ft. It has served me well.

with what? an 8inch 3/8 ratchet? how about a 24inch breaker bar? the amount of torque one can apply is highly variable.

as for op, just tighten the nuts to good enough and call it done

 

[andywander]

That will nullify the torque reading. Not that shock bolts need them anyway.

Actually, if you put the crowsfoot at exactly 90 degrees to the torque wrench handle, you will get the exact torque reading.

and even if it is not at exactly 90 degrees, the amount of extension or diminution of the torque arm from a crowsfoot will be so small I would not expect it to have any practical effect at all.

 

[Airframer]

^this. 90 degrees to the side.

 

[Mohawk Dave]

Thanks for all the replies. I even torqued my daughter's lumina dogbones to 30lb ft after changing plugs. I am a relative newbie at car repair and until I develope a feel for torque;I feel secure using a torque wrench cause I know it's done right not too loose or tight.

HUMBLE. very cool. And like the other guys said, just start working on stuff. Chasis and suspension...get good-n-tite.

But using a TW to learn values, props my man. You are taking the time to learn and that is seldom found. (More common on GJ of course)

I personally learned the hard way on bicycles/lawnmowers as a pre-teen, stripping out bolts/nuts.

 

[rockchucker]

tighten till they creek ! practice on a bolt that you just torqued. get a feel for what it takes to just move the nut or bolt. in a pinch i hook two combination wrenches together .

This is what I do to get a feel for the Torque Value.

I guess I'm one of those old school guys who think having torque specs for every little thing is overkill. Critical engine stuff like head bolts, connecting rods bolts, sure. Lug nuts, yeah them too but things like shock bolts ? WTF... A little common sense is all I've ever used.

Seems overkill but I do it anyways. Just as easy to get it snug then Torque it properly.

Just use the German method, torque everything........good-n-tite.

I thought that was the German word for Virgin? =)

For home use (not including critical engine parts), that's the way I am. In the shop working on other people's expensive equipment, everything gets torqued to spec. Not letting anything get out the door without double checking every nut and bolt.

For the OP, if you're at all concerned about something coming loose, just paint pen a line from the nut/bolt head to the surface. If it tries to come loose, you'll know with just a glance.

That doesn't really make sense to me about doing it at work but not on your own vehicles?

The paint line for reference is a great way to quickly check if things back off. Now that I understand completely.


Torque to Spec on everything you can get to is the way I do things.

 

[alan camby]

I fiqure torque from time to time without a torque wrench.

1 foot pound is pushing down on a foot long wrench/ratchet with one pound of force.

If i need 100 foot pounds, I push down on a 2 foot ratchet/wrench with 50lbs of force.

I weigh right at 170lbs, so..
if I have a trailer ball that needs torqued to 450lbs ft. I rotate the hitch 90 degrees in the receiver and put a mark at 2.6 feet on the ratchet breaker bar and get right at 450lbs ft if I put all of my weight at the mark. No jumping, just put all my body weight on the mark.

 

[diesel research]

the 90º thing is NOT "exact", but it is very close.

 

[RECox286]

My brother torques everything in his path, choosing to tighten the

fastener until it starts to get easier to turn, then he stops ! I don't

know, but it seems to work for him. I think I wouldn't touch that with

a 10' cheater bar...but I just had to say it.

Get some or make some adapters that you can use on odd placed

fasteners, like most of the rest of us do. It's not that hard.

Uncle Bob

 

[shampoop]

Like has been said, for those types of things, german spec works great. For small fasteners, I like to choke up my grip on my 3/8" ratchet as close to the head as possible. Makes it pretty foolproof on stuff around 12-14mm.

IMO, if the torque spec is above 80 ft/lbs (most asian car lug nuts) You don't need to worry about breaking anything unless you're a real idiot.

 

[Leadberry]

Like has been said, for those types of things, german spec works great. For small fasteners, I like to choke up my grip on my 3/8" ratchet as close to the head as possible. Makes it pretty foolproof on stuff around 12-14mm.

IMO, if the torque spec is above 80 ft/lbs (most asian car lug nuts) You don't need to worry about breaking anything unless you're a real idiot.

That's the problem. A lot of people out there think fasteners require a lot more torque than they actually do. Before I started working in a tire shop, I never really used torque wrenches. I couldn't believe how little torque we were using to fasten these lug nuts. Mind you, I was raised by a man who (I now know) overtightened the hell out of everything. A camshaft sprocket bolt and about a dozen other broken bolts later, I tend to use torque wrenches on engine parts and lug nuts.

Like most others here, I go German spec on suspension and body pieces. Keep in mind that does not mean to tighten until you can't any more. I look for the rapid rise in torque. If something bad will happen if the fastener comes loose, I give it two grunts when the torque starts to peak. Larger non-important fasteners will get one grunt, and small ones will get none.

YMMV

 

[nomuffintop]

What type/brand of torque wrench are you using? Im looking to buy one and would like to buy a quality one. I work as a tech for a dealership btw.

 

[Mohawk Dave]

That's the problem. A lot of people out there think fasteners require a lot more torque than they actually do. Before I started working in a tire shop, I never really used torque wrenches. I couldn't believe how little torque we were using to fasten these lug nuts. Mind you, I was raised by a man who (I now know) overtightened the hell out of everything. A camshaft sprocket bolt and about a dozen other broken bolts later, I tend to use torque wrenches on engine parts and lug nuts.

Like most others here, I go German spec on suspension and body pieces. Keep in mind that does not mean to tighten until you can't any more. I look for the rapid rise in torque. If something bad will happen if the fastener comes loose, I give it two grunts when the torque starts to peak. Larger non-important fasteners will get one grunt, and small ones will get none.

YMMV

lol. I do the grunt thing as well.

 

[andywander]

the 90º thing is NOT "exact", but it is very close.

I actually did the math, vector diagrams and all, and it IS exact.

 

[greasemonkey44]

i cant say ive torqued any suspension parts except bearings; just put them on as tight as they came off

 

[Mohawk Dave]

the 90º thing is NOT "exact", but it is very close.

I actually did the math, vector diagrams and all, and it IS exact.

My brain hurts thinking about this....When a TW is placed on the pictured box end-crowsfoot thing,

1. It seems the leveraged torque would change as you are pulling away or pushing toward the fastener, instead of turning it.

2. For the 90deg thing to work, the TW would have to be at 90deg...because as you fasten the TW would turn...well, I guess a ratcheting one would, but not a beam.

I'm not doubting anyone, I'm just drinking Mtn Dew trying to wrap my head around this.

EDIT: can someone spoon feed these equations/black magic math to me. Thanks!

 

[Leadberry]

What type/brand of torque wrench are you using? Im looking to buy one and would like to buy a quality one. I work as a tech for a dealership btw.

Split beam clickers are nicer to work with, imo. Fewer moving parts and you can get them with a flex ratchet head. With the micrometer (twisty) clickers, if you don't wind them back down after use you will eventually alter the spring rate of the spring, throwing off the accuracy. If you do work with LH threads, however, you'll need to buy another wrench as split-beams only work in one direction; micrometer-types work in both directions. I have heard that split-beams hold calibration longer, but that's just conjecture.

The big players are Precision Instruments and CDI Torque. PI makes or has made split-beams for SO in the past I believe, and CDI is a subsidiary of SO. You can save significant dough by buying the PI/CDI brands, however. I would recommend either brand regardless of which type of wrench you choose.

At home I use PI split-beams and I love them. At work I use Chinese Steelman micrometer-type wrenches (supplied) and they are absolute garbage.

lol. I do the grunt thing as well.

Great minds think alike!

I actually did the math, vector diagrams and all, and it IS exact.

I used trig rather than vectors, but checked this as well and can confirm that the torque is exactly the same.

 

[Leadberry]

My brain hurts thinking about this....When a TW is placed on the pictured box end-crowsfoot thing,

1. It seems the leveraged torque would change as you are pulling away or pushing toward the fastener, instead of turning it.

2. For the 90deg thing to work, the TW would have to be at 90deg...because as you fasten the TW would turn...well, I guess a ratcheting one would, but not a beam.

I'm not doubting anyone, I'm just drinking Mtn Dew trying to wrap my head around this.

EDIT: can someone spoon feed these equations/black magic math to me. Thanks!

Torque is scientifically known to be given by the following equation:

tau = rFsin(theta)

In this case,

tau = torque in in-lbs
r = magnitude of lever arm, or distance from point of application to point of measurement (in inches)
F = magnitude of applied force
theta = angle between force vector and lever arm vector (in degrees)

Assume we have an 18-inch torque wrench applied directly to a fastener. Our equation then reads:

tau = 18F(1) = (18.00)F

In this case sin(theta) = 1 because theta = 90 degrees or pi/2 radians. In lay terms, when you push down on a torque wrench you're applying the force perpendicular to the wrench itself, thus the full applied force is being used to rotate the fastener.

Now consider the case where a 2-inch torque extension is added to the wrench at a 90 degree angle. r changes as follows:

r = sqrt(18^2 + 2^2)
r = sqrt(328.00)
r = 18.11 inches

We are able to figure this out because the torque wrench and the extension form a right triangle. We used the Pythagorean Theorem to solve for the hypotenuse of this triangle, which happens to be the new distance between our fastener and the point of application of force on our torque wrench.

Theta also changes. Again we use trig.

18.11sin(theta) = 18.00
theta = sin^-1(18/18.11)
theta = 83.68 degrees

If you don't know trig, you'll just have to trust me here as I could spend a long time explaining this one.

What happens when we plug our new values into the original equation?

tau = 18.11Fsin(83.68)
tau = (18.00)F

Notice that I never chose a value of F. That means the torque will be accurate with the extension no matter how much force you apply. Even with rounding errors, this measurement is accurate to roughly .00006 in-lbs. Thus, the use of a torque extension does not affect applied torque so long as it is installed at an angle of 90 degrees to the length of the torque wrench.

Edit: I should note that you did have the right idea. These calculations assume that the torque wrench and adapter assembly is rigid. As the torque wrench flexes under load, our r and theta values will change, which would throw off our torque readings. I can only assume that this is why torque wrench manufacturers recommend that torque wrench extensions be installed in-line with the wrench itself, rather than at an angle.

 

[theknurl]

Leadberry;
thank you!

 

[Mohawk Dave]

Leadberry; yes, thank you! it does make sense. I can read trig, I just can't write it. Serious.

 

[toolaholic]

What type/brand of torque wrench are you using? Im looking to buy one and would like to buy a quality one. I work as a tech for a dealership btw.

I use a kobalt 3/8 and 1/2 drive. Both USA models. Plus a gearwrench 1/4 and just purchased 3/8 flex head (85056). Gearwrench and Kobalt great for me but for daily service work I don't know how they'd hold up.

 

[nomuffintop]

Thanks guys. Just what i was looking for.

 

[crewchief888]

I heard a number of years ago that the average guy can pull about 100 lbs ft. It has served me well.

i must be above average,
back in the day i could pull 600 lbs...

 

[Shadowdog500]

I actually did the math, vector diagrams and all, and it IS exact.

+1!

To show this, I just did this in a minute or so in the force effect app. The torque is the same at the end of the wrench and at the end of the extension. Force effect is a great app to have on your device.

Chris

 

[driver]

with what? an 8inch 3/8 ratchet? how about a 24inch breaker bar? the amount of torque one can apply is highly variable.

as for op, just tighten the nuts to good enough and call it done

Your right, I should have said 100 lbs. so on a 1 ft. bar would be 100 lb.ft.