Question about torque wrench?
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Senior User
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From: San Antonio USA
Question about torque wrench?
Is there such a thing as a way to calibrate or test the accuracy of a torque wrench? I am asking of course because I snapped a bolt off with my torque wrench set at 40 ft/lbs. last night. I had often wondered if the wrenches were accurate, but had never worried about it. This particular wrench is one that you set and it clicks when the desired torque has been achieved. The bolt I broke was actually one of the last bolts I tightened down, and the wrench seemed to work fine on the previous bolts.
Mountain Pass
Joined: Feb 2002
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From: Canada
Question about torque wrench?
Yes, there is a way to have wrenches calibrated. First, though, and I don't mean to sound like a jerk... Is it a decent tool, worth calibrating? If it's a $10 wrench you're going to get the accuracy of a $10 wrench. If it's a high quality piece that may have got out of wack for a number of reasons, take it to your dealer or tool store and they should be able to help you out. I learned the importance of accuracy when I was a transmission tech. Tighten a valve body down innacurately and you CAN have problems you never dreamed of! Hope this helps. Good luck.
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Question about torque wrench?
Maybe it was not the wrench. What kind of bolt was it? I have seen bolts made to a low grade snap when taking them OFF let alone tightening them to low torque spec. If it was a perviously used bolt, it could have streched on install and upon re-install, broke off. I see this a lot with low grade stuff right at the shoulder. Just a thought.
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From: San Antonio USA
Question about torque wrench?
This was a used bolt that I was re-installing on the rear diff cover so I guess this could be a possibility. I paid a pretty fair price for the wrench so I will take it in to the auto parts store and see about having it checked out. Thanks for the quick responses.
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Question about torque wrench?
[updated:LAST EDITED ON 14-Mar-02 AT 02:18 PM (EST)]Are you sure it wasn't supposed to be 40" lbs not 40 ft lbs ?
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
[font color=blue]Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [font/]
78 F-150 429CJ,Silver, Explorer Pkg.
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Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
[font color=blue]Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [font/]
78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
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Senior User
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From: San Antonio USA
Question about torque wrench?
Sure hope so other wise the Ford spec book I was using was wrong. I will check it today and make sure. I sure hope I don't have donkey ears scraping the ceiling about this.
New User
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Question about torque wrench?
[updated:LAST EDITED ON 15-Mar-02 AT 09:47 PM (EST)]I checked two sources.
One says 30-40 Ft lbs
the other says 40 "lbs
Just pass snug ???
I just found another source>
it says 30-40 Ft lbs .
This looks like the right spec.
It looks like Murphy show up at the wrong time for you.
I know I've always been able to turn them off with just a short wrench.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
[font color=blue]Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [font/]
78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
One says 30-40 Ft lbs
the other says 40 "lbs
Just pass snug ???
I just found another source>
it says 30-40 Ft lbs .
This looks like the right spec.
It looks like Murphy show up at the wrong time for you.
I know I've always been able to turn them off with just a short wrench.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
[font color=blue]Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [font/]
78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
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Logistics Pro
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From: suburban atlanta
Question about torque wrench?
[updated:LAST EDITED ON 16-Mar-02 AT 11:50 AM (EST)] If this is a bolt that holds the gasketed differential cover on, there is no way that 30-40 ft/lbs of torque are correct. The sheet metal of the cover would be so distorted at the bolt holes that it would more than likely end up leaking. If you look at the head of the bolt, and it has a raised edge all the way around, with no markings, it is a 'pan gasket bolt' that will break with the torque you applied. For it to handle that kind of torque, it would have markings on the head- dashes pointing radially as an example. The lowest grade of bolt has no markings..and a raised edge around the head or a depressed center if you want to look at it that way.
40" lb is about 4 ft lb, which makes sense for a sheet metal cover.
tom
40" lb is about 4 ft lb, which makes sense for a sheet metal cover.
tom
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Brett Foote
Senior User
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From: san diego usa
Question about torque wrench?
Tom, it's not 40 inch-lbs, unless you want a leaky rear housing. 
That's a hair over 3 foot-lbs. Even oil pan bolts get tightened more than that.
The specs for the Dana 44, 60 and 70 diff cover bolts are 30 FOOT-pounds. Most others are around the same. The stamped steel covers on most diffs are much thicker than just sheet metal.
A simple way to check your wrench is to stick an old socket on it and clamp the socket in a vice so that the wrench is free to rotate. Rotate the handle to a horizontal position. Hang a known weight on it using a loop of wire. Measure the distance between where you hang the wire and the pivot point of the wrench head, and divide by 12. Then multiply this by your weight.
For example, if you hang a 30lb weight at 10 inches, your applied torque is 30
10/12)=25ft-lbs. If you have a click-type wrench, you would adjust the setting and see if it clicks when it's set near 25 ft-lbs.
If you can't find a good weight, use a bucket & fill it using 1 gallon water bottles... every gallon you add weighs 8.3 lbs.
That's a hair over 3 foot-lbs. Even oil pan bolts get tightened more than that.The specs for the Dana 44, 60 and 70 diff cover bolts are 30 FOOT-pounds. Most others are around the same. The stamped steel covers on most diffs are much thicker than just sheet metal.
A simple way to check your wrench is to stick an old socket on it and clamp the socket in a vice so that the wrench is free to rotate. Rotate the handle to a horizontal position. Hang a known weight on it using a loop of wire. Measure the distance between where you hang the wire and the pivot point of the wrench head, and divide by 12. Then multiply this by your weight.
For example, if you hang a 30lb weight at 10 inches, your applied torque is 30
10/12)=25ft-lbs. If you have a click-type wrench, you would adjust the setting and see if it clicks when it's set near 25 ft-lbs.If you can't find a good weight, use a bucket & fill it using 1 gallon water bottles... every gallon you add weighs 8.3 lbs.
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Question about torque wrench?
Excellent reply!
1 Imp gallon of water = 10 lbs
So,Just to add to that if you can get your hands on a metric
container 4.54 Litres = 10 lbs
I think 4.5 U.S. quarts is close to that figure too.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
[font color=blue]Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [font/]
78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
1 Imp gallon of water = 10 lbs
So,Just to add to that if you can get your hands on a metric
container 4.54 Litres = 10 lbs
I think 4.5 U.S. quarts is close to that figure too.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
[font color=blue]Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [font/]
78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
Posting Guru
Joined: Jun 2002
Posts: 1,146
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From: Colorado
Question about torque wrench?
Your best bet is to find a local calibration lab that does torque wrenches. To check a single point on any wrench is a fine quick check, but does not cover the range of the wrench. The water method is a so-so functional test, but doesn't take into consideration the weight of the handle, container, or what you use to hang it with, which can a factor on a long or heavy wrench! The angle the wrench deflects from horizontal when you hang the weight will also affect your test! Repeatabilty is something that needs to be checked as well.
If your wrench has been dropped, even once, (and all have been if they are used at all), that can change the calibration too.
To sum it all up, I again suggest finding a local lab and having your wrenches cal'd by them. This includes dial, break type, or deflection beam. Cost should be nominal, and will save you lots of grief down the road!
To ease your mind, I have been calibrating tools for 20+ years.
If your wrench has been dropped, even once, (and all have been if they are used at all), that can change the calibration too.
To sum it all up, I again suggest finding a local lab and having your wrenches cal'd by them. This includes dial, break type, or deflection beam. Cost should be nominal, and will save you lots of grief down the road!
To ease your mind, I have been calibrating tools for 20+ years.
Post Fiend
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From: USA
Question about torque wrench?
[updated:LAST EDITED ON 05-Jun-02 AT 04:26 PM (EST)]So Rikfish
When are you starting your bussiness ,we will all send you our
wrench's!!!!!
''
')'
Rich
Ford Trucks Built Tough!
not with rocks
Watch out "X" Mayor of Truckville
When are you starting your bussiness ,we will all send you our
wrench's!!!!!
''
')'Rich
Ford Trucks Built Tough!
not with rocks
Watch out "X" Mayor of Truckville
Posting Guru
Joined: Jun 2002
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From: Colorado
Question about torque wrench?
[updated:LAST EDITED ON 05-Jun-02 AT 05:45 PM (EST)]Rich,
Hmmmm, not a bad idea... Shipping would probably be more than the cost of calibration! That, and too many labs with torque capability around here.
One quick suggestion for all users. After you are done using your adjustable breakover type wrench, set it to the lowest setting. The springs tend to develop a memory.
Hmmmm, not a bad idea... Shipping would probably be more than the cost of calibration! That, and too many labs with torque capability around here.
One quick suggestion for all users. After you are done using your adjustable breakover type wrench, set it to the lowest setting. The springs tend to develop a memory.
Post Fiend
Joined: Nov 2001
Posts: 14,947
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From: Topsfield, MA
Question about torque wrench?
Ya, def relieve the stress on that spring.
Primary rig is:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, and some 32" BFG Muds
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Pictures are in!!
Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
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Primary rig is:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, and some 32" BFG Muds
.Pictures are in!!
Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Top speed is 65mph, Go Baby Go!