Lugs OVERTIGHTENED

[stumps]

...Gave the threads all some high temp grease on the reinstall.

That's a very specific no-no on lug bolts. They are designed to be left dry. If you use grease on the threads, you will over tighten them, and they may very well back off while driving.

The only lubricant that is acceptable on lug nuts/bolts is something very light weight like 3-in-1 oil, or one of the penetrating oils, like Kroil or PB Blaster. You definitely shouldn't use any EP oils (hypoid), or greases.

-Chuck

 

[ZRacer]

That's a very specific no-no on lug bolts. They are designed to be left dry. If you use grease on the threads, you will over tighten them, and they may very well back off while driving.

The only lubricant that is acceptable on lug nuts/bolts is something very light weight like 3-in-1 oil, or one of the penetrating oils, like Kroil or PB Blaster. You definitely shouldn't use any EP oils (hypoid), or greases.

-Chuck

On race cars we use an anti-seize compound specifically designed for lug nuts. It has saved our lug nuts from being stripped since they are on and off so much. I would think this would be perfect for the big lugs on the Deuce.

 

[KsM715]

My father-in-law hauls for the local co-op and uses anti-seize on the lugs of his truck and trailer and Ive never heard him ever mention the lugs coming loose.

 

[Nonotagain]

Out of the dozen or so military trailers that I have purchased in the past few years, both of my M796 and both of my M1061's have had anti-seize on the lug nut threads.

The M101's, M116's, and the M105's were all dry threaded.

Both of the M796 trailers had supposedly come out of overhaul before my purchase. They both had a copper based anti-seize on the threads.

DUG

If the budget will allow, purchase a tap and die and run it down the threads. If the lugs were tightened to the point that you couldn't easily remove them, they could be galled and cause you problems at a later date and time.

 

[ZRacer]

I may take flak over this suggestion/question... but here goes...

Does anyone think that one of these torque multipliers would be any good for Deuce lugs? Its only 1/2" drive, and it looks a bit weak for large lugs. (After reading the reviews on HF, I think it wouldn't stand up to heavy duty use). Does anyone know if they make these in a more robust variant?

 

[DieselBob]

To deal with things like frozen / overtightened lugs on larger vehicles you would need something more along the lines of a geared lug wrench or something like this. My

 

[Ol-Paint]

In general, lubrication shouldn't make a difference to the holding power of the stud/nut combination. HOWEVER, the torque should be adjusted to match the lubricant. Depending on what you are using, the lubricant can lower the torque required by 60% (or more).

There are a number of resources out there with torque guidelines (Engineer's Handbook, Standard Handbook of Machine Design, etc.), most giving torque as a function of "nut factor" (essentially a term including the coefficient of friction of the nut, stud, and antiseize, among other factors) multiplied by the diameter multiplied by the force or tension desired in the joint. Usually, the force is on the order of 80-90% of the fastener yield strength. An even better option would be to contact the anti-seize manufacturer to get their assessment of the correct reduction from dry torque, since they will have done testing to determine the properties of their product.

The TM may have guidance in this area? I don't have a deuce (or 5-ton), so I don't know what the TMs have to say.

Douglas

 

[DUG]

The reason the lugs were hard to remove is because the shop doing the tire swap installed them using a professional grade 1 inch drive gun fed by an industrial compressor.

When I tried to remove them with my 1/2 drive gun, a 3/4 gun, a 1 inch (HF) gun and a 3/4 inch breaker bar with a 6 foot cheater pipe those attempts failed. When I switched to a 1/2 inch air hose and 3/8 fittings the HF 1 inch gun got the job done. I suspect the 3/4 inch gun would have done the job but I returned it to keep the cost of this project from rising.

A lot of the lugs were rusty looking so I added a dab of grease to each one. I know that this will affect the torque value. I am not worried about it causing the lugs to come loose. In the Navy we often use anti sieze or grease on the lugs to fight the effects of salt spray on the flight deck.

The main thing I learned here is to make sure the shop you select torques your lugs properly. While this whole deal was a PITA, I don't regret hiring the tire swap out. In the end it cost about 200 dollars extra for a HF 1 inch gun, 1/2 hose, 1 inch to 3/4 adapter, and misc fittings.

 

[blisters13]

I'm pretty sure (and expect to be corrected here if wrong) that regular bolts for common application should be torqued dry unless otherwise specified, because the torque value is based upon bolt stretch. However, lug nuts are a combination of bolt stretch, and more critically, the friction at the tapered seat of the nut into the wheel plate (hub). Note that the inner wheel lug nut (the "thimble") will stretch VERY LITTLE when the outer nut is applied as the length is less than 1/4" from the hub of the nut to the bottom of the outer lug nut and it's very large in diameter compared to the lug stud. The actual axle lug stud is what stretches the most.

Therefore, a minimal amount of anti-seize applied to the threads AND NOT THE TAPERED AREAS should be acceptable. The finished torque applied will be, in large part, the friction of the nut at the wheel stud hole taper.

I have found MANY TIMES that threads allowed to rust will gall and be ruined when the dry, rusty nut is turned. Preventing rust is important here.

I guess we all learned to give a torque spec to the tire shop, whatever the vehicle!

 

[KsM715]

Does anyone know if they make these in a more robust variant?

They do! refer back to post #8

 

[jimmcld]

I used a 3/4 hydraulic impact, rated at 1400 ft.lbs., on my 5 ton. They wouldn't budge. I borrowed a 1 in. pneumatic impact, ran 3/8 hose and fittings at 175 lbs. pressure to break them loose. It still took some hammering on some of them. I believe they had been on the truck for 15 years.

 

[OPCOM]

I've always run 300-400 on mine. When I had alll the wheels of the M8109, every drum stud was meticulously washed with solvent and wire brushed and every inner and outer nut similarly cleaned and inspected. Anti-sieze was used on them all, and there has been no issue since. I hope you inspected the 'stud nuts' for broken or bad threads. I found ten on the truck and rejected them. The 3-stud picture shows from left to right, a new replacement, a good used one, and a reject. The 4-stud picture shows a new, two usable ones with slight damage, and a reject. If more than 1/4" of thread was missing on any stud, it went into the scrap metal bin. Studs and nuts are cheap insurance.

 

[forestMog]

When I encounter a bolt that is too hard to easily remove, I try to tighten it a bit more, then try to remove again. Sometimes this helps, most times not. I don't understand why it works but it does.

 

[KsM715]

Its hard to explain but the nuts and bolts are like gears. When you tighten them down they push against one side of the threads, when you stop, the spring action of the stretched bolt and compression from the rim push the contact point to the other side of the threads. When they sit for a long time that way they rust together but there is a microscopic open area on the other side. When you go to remove them and try to tighten them first your breaking that rusty area and and that open area gives you a little room to move, once the rust is broken loose you can usually spin them off. (can anyone understand that?)

 

[forestMog]

Its hard to explain but the nuts and bolts are like gears. When you tighten them down they push against one side of the threads, when you stop, the spring action of the stretched bolt and compression from the rim push the contact point to the other side of the threads. When they sit for a long time that way they rust together but there is a microscopic open area on the other side. When you go to remove them and try to tighten them first your breaking that rusty area and and that open area gives you a little room to move, once the rust is broken loose you can usually spin them off. (can anyone understand that?)

Very good explanation KsM715! You are an excellent teacher! I wonder if this is taught formally. It should be.

 

[KsM715]

I wouldnt go that far. I often have a hard time trying to explain the simplest things sometimes.

 

[Ol-Paint]

I'm pretty sure (and expect to be corrected here if wrong) that regular bolts for common application should be torqued dry unless otherwise specified, because the torque value is based upon bolt stretch. However, lug nuts are a combination of bolt stretch, and more critically, the friction at the tapered seat of the nut into the wheel plate (hub). Note that the inner wheel lug nut (the "thimble") will stretch VERY LITTLE when the outer nut is applied as the length is less than 1/4" from the hub of the nut to the bottom of the outer lug nut and it's very large in diameter compared to the lug stud. The actual axle lug stud is what stretches the most.

Therefore, a minimal amount of anti-seize applied to the threads AND NOT THE TAPERED AREAS should be acceptable. The finished torque applied will be, in large part, the friction of the nut at the wheel stud hole taper.

I have found MANY TIMES that threads allowed to rust will gall and be ruined when the dry, rusty nut is turned. Preventing rust is important here.

I guess we all learned to give a torque spec to the tire shop, whatever the vehicle!

I do the same on my car--anti-sieze on the threads, none on the washer surface.

The key is to know what torque is specified--wet or dry & what surfaces are to be lubricated. Stretch may or may not be desirable, it depends on the material properties of the bolt. In general application, standard torque values are usually used to tighten the bolt to 80-90% of the yield strength, the point where the deformation of the fastener changes from elastic to plastic. Most standard torque tables found in engineering handbooks or on the web will have notes stating the conditions for which the torques are valid (no lube, clean surfaces, as new threads, & the fastener specification being typical). Most often, "stretch" becomes part of the discussion when a fastener is to be tightened enough to induce loads that cause plastic (permanent) deformation of the fastener. In these applications, the fastener is not intended to be reused.

Where reuse is required, as in lug nuts/wheel studs, the stretching of the fastener should be purely elastic and the stud will return to it's original length when the tension is removed.

In either case, it isn't really the torque that is important, it is the clamp load of the fastener that is the primary goal. Measuring the stretch of the fastener is an accurate way of determining the clamp load if the material properties are known, but usually requires specialized fasteners and/or measurement tooling. Converting preload into an applied torque is much more accessible & practical, even though it involves a host of assumptions. It is also very inaccurate. The only reason it is the preferred method in general use is because it is much easier and very inexpensive.

Others in this thread have pointed out a number of problems with the use of torque-tension relationships. Rust, thread damage/galling, galling of the washer surface, dirt, plated or unplated fasteners, all change the torque required to develop a specific joint preload. The situation gets even more difficult to manage when "wet" torque is specified. Light oil, heavy oil, grease, molybdenum disulfide, etc., etc. all have different coefficients of friction, ranging from the same as the bare fastener to 1/3rd or less.

In critical applications, it is not uncommon to build an instrumented test joint and measure torque values for a representative series of fasteners in order to come up with the torque value that is published. I would not be surprised if this type of testing was done by the manufacturer at the time the axles were designed/tested (or that the manufacturer's R&D section had done generalized testing) from which the recommendations were originally drawn.

Of course, all of the foregoing is wonderful & lovely, but it all boils down to knowing the manufacturer's recommendation, how you may have modified the manufacturer's assumptions, and understanding that things like wheel lugs are thankfully overdesigned enough to be pretty forgiving of misguided wielders of impacts.

Douglas

 

[rat4spd]

Or instead of worrying about all those details, one could just check their lug nuts every now and then?

 

[DUG]

Or instead of worrying about all those details, one could just check their lug nuts every now and then?

What? Me worry?

 

[Ol-Paint]

Or instead of worrying about all those details, one could just check their lug nuts every now and then?

Well, yes, but where's the fun in that?!

Douglas