Posted: Sat Sep 24, 2016 3:51 pm Post subject: Re-installing tie rods
I have been putting my front end together on my M38. I might have missed it but I can't find a torque value for the nuts for the tie rod ends. I know it is easy to turn the castle nut down so tight that the cotter pin hole is above the castle nut slots. I have looked in the two M38 manuals and the civilian manual.
I was able to find the torque value for the clamps securing the tie rod ends into the rod.
There are several things to always keep in mind about torques.
1 - Specified Torque. A torque figure called out for a specific item or task. (Not all torques are called out in the maintenance manual for all fasteners.)
2 - Standard torques. These are torque spec's that apply to a certain size fastener with a certain thread pitch. They are usually listed several ways. Most modern manuals will carry a "Standard Torques" chart in the front of the manual or in an appendix.
3 - Dry torques. This is the most common standard torque. It means make sure all threads are clean and dry before applying the torque. A standard torque is always considered a dry torque unless Wet Torque is called out for that entry.
3 - Wet torques. This is a torque figure used for lubricated threads. This is not very common but when it is needed it will be called out as "Wet Torque"!
4 - Tension Torques. Are torque specs that apply to a fastener that maintains a holding pressure.
5 - Shear torques are minimum torques that ensure fastener is secure but the work of the fastener is not in clamping parts together. It is in provided support with the shaft of the fastener to prevent a pair of surfaces from moving across each others mating surfaces.
6 - Running torque is the amount of torque required to keep a fastener rotating within it's nut or threaded receptacle. This often associated with self locking devices and helps to insure the locking feature is gripping well enough.
All these torques require a tool that measures the amount of force required to rotate the fastener.
There are other methods to determine proper torque on fasteners.
1 - Bolt stretch. The amount of stretch is measured in most cases by degrees of rotation after reaching a pre-determined point.
So as you perform maintenance tasks while following the appropriate manual when a specified torque is listed use it. If no specified torque is listed for a fastener then use the standard torque tables. Read the directions on the torque table to determine how to use the table. Most require you to know something about the fasteners themselves and the material they hold together. Here are a few things you need to know about your fasteners before you go to a standard torque table.
1 - Grade of fastener. IE Grade 5 or grade 8. Standardized aviation hardware will often list grade as a function of the fastener's part number such as AN-XX or NAS-XXX or MSXXXXX. Different bolt grades will use different standard torque charts. In either case there are head markings that help ID grade.
2 - Size of fastener. Diameter, clearance tolerance and thread pitch are important here.
3 - Wet or dry torque.
4 - Shear or tension loads.
5 - Self locking features.
So that's the long answer!
That link to the 2A page document is not a good source document. That 60 Lbs was found on a different make / model vehicle chart and was assumed to be a good ball park figure.
Quote:
Tie rod ends 60 5
See note 5!
5) These specs were found online at Automotive Torque Specifications, an independent site whose author has gone to great lengths to compile torque specs. The source of these additional specs is not given, so I cannot vouch for their accuracy, but they seem reasonable.
I've only included those specs which were not found in a Willys manual, or which differed significantly from Willys specs. In most cases, the posted specs corresponded to Willys specs, but in some cases they differ significantly.
Compare them and make your own decision as to which to use.
When the maintenance task in the maintenance manual does not give a specific torque for a specific fastener then you are expected to go to a standard torque chart for your fastener's type, size and function and determine the torque yourself!!!
I would consider first the size which in this case is 1/2"-20NF. Since the steering tie rod joint is considered critical I would assume at least grade 5 but probably grade 8. This is a tension application. Here are a few examples of the charts we are talking about. Note that depending on the chart you use the torque dry for a 1/2" 20 Grade 8 bolt is 110 to 120 Ft Lbs.
Grade chart
This chart list values for both fine and coarse threaded bolts.
This chart only shows values for coarse threads.
This handy chart show values for both fine & coarse threads and wet and dry threads.
Be careful which chart you select. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Feb 20, 2007 Posts: 606 Location: Illinois
Posted: Sun Sep 25, 2016 9:21 am Post subject:
Since the nut in question is a castellated nut wouldn't it need unique torque specifications since part of the threads are cut away? _________________ 1951 M38
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