Checking the Toe Links without removing the panels

[tvacc]

Hello all,

Unless I am missing something here, I just adjusted and checked the torque on the toe link bolts by inserting a 15mm socket, then a universal and then 24inches of extension with a 3/38 torque wrench set to 540 Inch pounds.

I did the driver side (left) by going through the left side duct and the right side by going through the center duct. I could not use the right side duct as the engine pan gets in the way.

This was so easy that I almost think I did something wrong. We just did 2 cars in 20 min. Of course I have a drive on lift in my garage so that made getting the car up in the air easy.

comments?

[ace10]

does a torque wrench apply and measure force properly when applied through a U joint?

[TimMullen]

Originally Posted by ace10

does a torque wrench apply and measure force properly when applied through a U joint?

Only when the angle is "zero". If the U joint is "bending" the torque value would be off.

[sandsmuseum]

Originally Posted by ace10

does a torque wrench apply and measure force properly when applied through a U joint?

No it does not measure correctly. You can come close by making the angle as small as possible.

You can check this yourself by rotating a universal joint through a full circle. You will feel two cycles, with more and then less pressure.

While I have checked some bolts using this method, it is not recommended. You can get close by making sure the U joint is in a particularly good orientation. When worrying about a critical safety issue like this, I suggest taking off the panel.

My view, not necessarily the right view,

Michael

[tvacc]

The angle is really small. On the second car we used the right duct and only had a small angle on the universal.

It would seem to me that if you limit the leverage...and you are just turning the nut and not jamming the universal the reading should be real close.

Next time I change my oil...I will check them again both ways and see if I see any difference.

edit. I am also going to rig up a test bed and see if there is any difference when I tighten a nut with an universal and without.

[MattG]

Never use an extension when checking the torque; the extension itself will twist and throw off your torque setting. The only way to torque something properly is with the socket directly connected to the torque wrench. No extensions, no u-joints.

[xtn]

The twist in an extention will NOT throw off a torque setting. The twist will merely cause additional rotational travel required to REACH the torque setting.

In other words, the handle may have to travel further around, but eventually you reach your 60nm of torque, applied at one end of the extention, traveling through it, twisting it a bit, and still being applied to the nut in full.

This assumes a properly (slow and smooth) used torque wrench. If you are "bumping" it up to the value, then sure the twisting extention can act like a little spring absorbing some of your "bumping" energy without transmitting it. But used correctly, the extention does not effect ultimate torque delivery at all. Any claim that it does goes against all known physics.

xtn

[KingOfJericho]

Originally Posted by xtn

The twist in an extention will NOT throw off a torque setting. The twist will merely cause additional rotational travel required to REACH the torque setting.

In other words, the handle may have to travel further around, but eventually you reach your 60nm of torque, applied at one end of the extention, traveling through it, twisting it a bit, and still being applied to the nut in full.

This assumes a properly (slow and smooth) used torque wrench. If you are "bumping" it up to the value, then sure the twisting extention can act like a little spring absorbing some of your "bumping" energy without transmitting it. But used correctly, the extention does not effect ultimate torque delivery at all. Any claim that it does goes against all known physics.

xtn

yup.

[MattG]

Originally Posted by xtn

The twist in an extention will NOT throw off a torque setting. The twist will merely cause additional rotational travel required to REACH the torque setting.

In other words, the handle may have to travel further around, but eventually you reach your 60nm of torque, applied at one end of the extention, traveling through it, twisting it a bit, and still being applied to the nut in full.

This assumes a properly (slow and smooth) used torque wrench. If you are "bumping" it up to the value, then sure the twisting extention can act like a little spring absorbing some of your "bumping" energy without transmitting it. But used correctly, the extention does not effect ultimate torque delivery at all. Any claim that it does goes against all known physics.

xtn

Oops. Thanks.

[TimMullen]

Originally Posted by xtn

The twist in an extension will NOT throw off a torque setting. The twist will merely cause additional rotational travel required to REACH the torque setting.

+1 to what he said.

The often repeated warning to not use an "extension" is correct, but they are talking about a different kind of extension. In this case, we are talking about an extension (bar) that fits in a straight line between the socket and the ratchet (or torque wrench).

The "extension" that they warn against using is a tool that attaches to the ratchet, extends out parallel to the plane of the ratchet handle, and attaches a socket, open, or closed end wrench on the end of it. This extends the reach of the torque wrench. These tools are often used in industrial applications but the average mechanic never sees one (or even know they exist). A very small example of an "extension" is a claw-foot wrench. You can actually use this type of extension, but you have to do some math to figure out what the actual torque applied at the end of the extension is, as it will be different than what the torque wrench "thinks" it is...


Here's an example of an "extension" that "they" warn you not to use. It's the part that is attached to the torque wrench in the photo - the part that makes up the difference between "Normal Length" and "Extended Length".

[xtn]

Well sure an extention in the lever arm will throw it off! My diatribe should only be considered correct with regard to a standard socket extention used in line with the fastener being torqued.

Any configuration that moves the head of the torque wrench offline from the center of rotation of the fastener will throw off the reading. The further off-center you get, the more your wrench will read low.

xtn

[TimMullen]

Originally Posted by xtn

Well sure an extension in the lever arm will throw it off! My diatribe should only be considered correct with regard to a standard socket extension used in line with the fastener being torqued.

Any configuration that moves the head of the torque wrench offline from the center of rotation of the fastener will throw off the reading. The further off-center you get, the more your wrench will read low.

Yep. Like I said, +1 to what you said.

I was only posting that over the years, I have repeatedly heard the "no extensions - they are evil" comments. I've even seen that printed in the instructions that came with a torque wrench. But the "evil" stories come from the advice not to use the "lever arm extensions", not the normal extensions that everyone is so familiar with. Unfortunately, they are both called "extensions" so the common myth or "no (regular) extensions" is rather extensive out there in the world...

[xtn]

I guess it suprises me so many people own/use torque wrenches yet don't have the common sense understanding of how applying torque actually works. Uh, people, the units give you a hint; force times distance; applied around a center of rotation. A torque wrench controls one of the two variables - distance - so that the user can predictably control the other variable.

Change the distance from center, and the wrench doesn't know what the hell you're doing anymore. It will think you've gone off the deep end with all your wacky behavior. If you used your torque wrench in such a manner, and though it was right, and then couldn't find your torque wrench the next time you wanted to use it, it probably snuck itself off to an Alanon meeting after your shennanigans.

Now.... As long as you keep the head in line with the center of rotation of the fastener, you could transmit the torque through a rubber band for all it cares. And it would work. Well, it would work up until the rubber band exceeded it's failure point. But if your applied torque was low enough, the rubber band would twist up and twist up until it reached a point that it was stretched enough to deliver your applied force to the other end.

That is the famous "you could use a rubber band and it would work" mantra you hear going around so often in the pits. It's one of the nine Great Golden Truths of the world.