How to use a torque wrench.

I see threads about this and especially with oil changes and people over torquing. Like any tool, the first thing you must know is how to use it. Then you must know how to select the right one. It's pretty simple stuff for experienced but like anything else, can be hard if you have never done it before.

For a torque wrench, you want to first select the wrench depending on what you are torquing. Using the oil pan drain plug as an example, it is torqued to 30 lbs. ft.

Selecting the Right Tool

Now what you don't want to do is get a 1/2", 25-250 lbs. ft. kind of wrench. When selecting a proper torque wrench you want to have the needed spec some where in the middle of the range. For a 30 lbs.ft. spec I'd use a 3/8" wrench with a spec like 5-80 lbs. ft. Along with better accuracy in the middle of it's range, what this also gives is a wrench with a length on it that will allow you to place a constant even pull on it while providing feedback so you can feel the click. If you were to use a huge 1/2" one like the 25-250, you can easily over torque because the "click" you should feel will be faint and can easily be missed by the untrained hand.

Time to do Work.

So now you grab your 3/8 torque wrench. If the fastener is in a place that can't be reached like the oil pan drain plug you will need to add an extension to the wrench. This will not change the torque reading. Just make sure the extension is straight and perpendicular to the wrench. bring the wrench up to the spec needed by pulling the collar and twisting the handle or unlocking it and twisting etc. Each wrench may be different.

Now when tighten any fastener what you want to do is bring the nut or bolt up close to the desired spec and then have it that when the final torque is to be attained, it is reached in one smooth constant pull.

I like to pull with my right hand and stabilize the head of the wrench with my left. You want to grab the handle with your full palm on the end (like griping the bikes throttle). Choking up on the wrench or pressing your palm on the end of it will change the reading and will not give consistent readings time after time.

When you turn the wrench you want to pull towards yourself. This provides the most control.

So you are slowly turning the bolt, a 1/8 to 1/4 turn at a time, until you feel a small amount of resistance but below the torque spec. This takes practice and experience to get a feel for it. Then I start pulling in 1/2 turns. When you know you are reaching the spec, position yourself and the wrench so that you can produce a nice long pull. During that nice long and constant pull (no jerking) you will feel it click. This means that the the torque of the fastener is now at the point where you set the wrench. I one more time, pull gently to make sure you get that click with no further twisting of the fastener.

Now back off the wrench to "0" to maintain calibration, clean up and you're done.

So a break down

1. Select proper wrench with a range that places the spec near the middle.

2. Adjust the wrench to the spec you need.

3. Start tightening up the fastener by pulling the wrench towards you

4. When the fastener is getting tighter, start pulling in long constant pulls to bring up the torque and stop when it clicks. Gently pull one more time to verify the torque.

5. Back off the wrench, clean it and put it away.

6. Call it a day.

No more stripped drain plugs ok?

Hmmmm, wasn't that interesting. Today I was changing the oil and went to torque the drain bolt with my 3/8" drive torque wrench, it's one of those dial-it-in, use, and wait for the click. Well as I am applying more torque, something didn't feel right for 30 odd ft.lbs, so I slapped it in a vise and pulled on the wrench with the digital fish scale at the end. As I suspected, the wrench was not working.

Problem: I always dial out the setting to the lowest before storing. Well, it seems that I may have gone too far once and something didn't seat properly inside. After loosening the dial, shaking it a few times, redialed, verified with the scale, it's working fine again.

So...., even though you have the tools, know when to know that something just isn't right. 30 ft.lbs of torque is not nose-bleed tight and with a foot of lever arm, that's 30 lbs applied at the end; not much. In relationship, most auto wheels are torqued 76 to 100 ft.lbs. How many times did you cuss at the tire shop when you're out there stranded trying to loosen the lug nuts with your 20" tire iron?

Long story short, sometimes feeling it and knowing what it should feel like is your second measure for not screwing it up.

bd43 said:

Hmmmm, wasn't that interesting. Today I was changing the oil and went to torque the drain bolt with my 3/8" drive torque wrench, it's one of those dial-it-in, use, and wait for the click. Well as I am applying more torque, something didn't feel right for 30 odd ft.lbs, so I slapped it in a vise and pulled on the wrench with the digital fish scale at the end. As I suspected, the wrench was not working.

Problem: I always dial out the setting to the lowest before storing. Well, it seems that I may have gone too far once and something didn't seat properly inside. After loosening the dial, shaking it a few times, redialed, verified with the scale, it's working fine again.

Long story short, sometimes feeling it and knowing what it should feel like is your second measure for not screwing it up.

Click to expand...

This may be why the Air Force requires you to "break" a torque wrench before use a couple of times (our workbenches sometimes have two or three sockets welded to a plate and screwed to the workbench just for that purpose). Interesting!

I use the German torque wrench method. It's called "guut-en-tight"

I think I've heard more stories about stripped this-es and that-ses from using a torque wrench, than not. Not suggesting you don't use one - you learn how tight is tight enough by stripping something here or there....as they say: "tight enough is where you strip the threads, but just a quarter turn before that"

Using these on oil filters though amuses me...there's instructions on the box that don't involve a torque wrench.

Good post for those that do: thank you!

There's also this guy.


Its pretty hard to overtighten with this type.

While you don't have to use one, it's true that you should. The biggest problems that happen are mostly not the tools fault but the user of the tool. Most people here are not professionals and don't have the skill to know the feel. Before you can even use it you must know how. When you know, you won't have problems. This is mostly for the people out there that have no clue with what they are doing and are learning.

Each to their own. It's not my stuff they are working on.

Truthfully I put my entire front end back together including fork clamps, axle bot and calipers without a torque wrench. BUT, I know and trust myself because I know I have these skills. And if a problem arose, I'd be able to catch it pretty fast.

At my work, we build and repair corporate aircraft. Just about every bolt needs to be torqued to spec before it gets an airworthy release. I suspect the engineers gave the torque ratings for a reason. Sure, we could just use the ol' "feel" method; I'd rather not fly on a plane that had that type of work done on it... metal fatigue anyone? If using a torque wrench is good enough for a corporate jet, it's good enough for my lowly FZ6.

^^^ As someone who flies: thank you!

At the same time, the weekend mechanic needs doesn't get the same experience you do.

Plus I wonder (based on the "O shoot" threads) if the specs are for parts when initially assembled vs. maintenance? Pure speculation on my part here.

FizzySix said:

^^^ As someone who flies: thank you!

At the same time, the weekend mechanic needs doesn't get the same experience you do.

Plus I wonder (based on the "O shoot" threads) if the specs are for parts when initially assembled vs. maintenance? Pure speculation on my part here.

Click to expand...

No the spec is the spec. Every size fastener has it's appropriate range depending on the grade. Actually there is a chart in the fz6 manual i believe. Now this is just a guideline but most of the time specs fall within a certain range. Uglyguitar has it right. I see a bike like an aircraft. There is no room for error. If it happens out on the road, like in the sky, you are most likely going to come crashing down.