Watch your lug nuts

[dave11]

One thing that is overlooked is often times veiwed as a good thing when it is not. Anti-seize. when used correctly it is an amazing product. use a t-spec for a clean/dry state on a lubricated fastener and all you have is a lubricated over-torqued fastener. Oh, and the t-spec for your taco---what year? either 76(up till 99ish) or 83(2000 plus).

One caveat about anti-seize compounds though, not sure if this is what you are referring to. The torque settings recommended by manufacturers assume the fasteners in question are dry. If you lubricate them in any way, the proper torque setting becomes much higher, though you now have no idea what it really should be.

 

[semipro]

One thing that is overlooked is often times veiwed as a good thing when it is not. Anti-seize. when used correctly it is an amazing product. use a t-spec for a clean/dry state on a lubricated fastener and all you have is a lubricated over-torqued fastener. Oh, and the t-spec for your taco---what year? either 76(up till 99ish) or 83(2000 plus).

One caveat about anti-seize compounds though, not sure if this is what you are referring to. The torque settings recommended by manufacturers assume the fasteners in question are dry. If you lubricate them in any way, the proper torque setting becomes much higher, though you now have no idea what it really should be.

I've wondered about this.

Thinking out loud here; on one hand, as you've said, the addition of anti-seize reduces friction, (presumably only on threads unless you put it between nut and wheel also). But does this really mean the lug nut is more likely to loosen?

On the other hand, adding anti-seize allows you to stretch the lug stud more with the same amount of applied torque because of the reduced thread friction. Whether you use anti-seize or not, the stud stretches elastically, acting like a spring, holding the nut in contact with the wheel, preventing it from loosening.

Perhaps its really the friction between nut and wheel that keeps the lug nut from loosening. So if you only put anti-seize on the threads you should not have to increase the torque????

I do know I've been using anti-seize on my threads for 20 years on cars, trucks, trailers and have never had a lug nut loosen by itself nor have they seemed loose when I remove them. That's purely anecdotal though and doesn't mean I shouldn't be torquing them tighter.

 

[Mcbride]

Some of you might find this an interesting little read.

http://www.engineersedge.com/wwwboard/posts/13070.html

 

[dave11]

Some of you might find this an interesting little read.

http://www.engineersedge.com/wwwboard/posts/13070.html

Interesting article, but it's not complete. To my knowledge, there has never been a published study testing any of the ideas listed here or in that article, at least not that are applicable to the lug nut issue. I guess all we have are educated guesses.

There are good reasons to suspect though that any lubrication of the threads will change the proper torque setting. That is why most fasteners are meant to be torqued while dry, and why only that torque setting is listed. A lubricated lug nut will thread forward more easily of course, and therefore fasten too tightly to what it's holding, but the correlate is that it will also loosen more easily. You can prove it yourself, if you torque a lug nut to 100 ft-lbs, then loosen it by hand. Then try it again with a lubricated nut/threads. The lubricated lug nut will loosen easier, which is a problem in most settings.

While translational motion may be the primary reason any lug nut loosens (as stated in the article), no doubt that assumes that the wheel bearing is not at all worn, and that the tire is perfectly balanced, etc. Any type of wear or misalignment can introduce non-translational forces into the picture, and would raise the chance of the lubricated lug nut loosening.

Many folks say they always use anti-seize and have never had a lug nut come loose. That may be true. My original point was simply that if you use anti-seize or any other lubricant, you cannot, by definition, know what the proper torque is for those lug nuts, unless the manufacturer has published them for the particular lubricant you are using.

 

[dave11]

Back in the 70's, when anti-seize first started to catch on, the packaging specifically said not to use it on lug nuts and wheel studs, though I have no idea if it still says that. You could only use it on whatever threads, if any, protruded through the end of the lug nut once it was properly fastened.

I suppose an anti-seize compound that did not affect friction between the nut and the stud would be okay, though I'm not sure if such a thing is available, or even possible.

 

[FordMastertech]

The 5/8 lugs on my race car are torque to 100 lbs. My trucks are usually 85, on a Suburban and F350 dually.
I used to be a automotive and body tech. So, I always check them after having my tires serviced.

Thats a little light on the torque on that F350, They should be set at 165 FTLB.

Ford Truck Shop Manual Torque Specifications

Description Nm lb-ft
Spare tire carrier bolts 20 15
8-Lug M14 wheel bolts — F250/350 224 165
10-Lug M14 wheel bolts — F450/550 224 165

WARNING: Retighten wheel nuts within 160 km (100 mi) after a wheel is reinstalled. For dual rear wheel (DRW) only, a second retightening is required within 800 km (500 mi). Wheels can loosen after initial tightening. Failure to follow this instruction may result in serious injury to vehicle occupant(s).

NOTICE: Failure to tighten the wheel nuts in a star/cross pattern may result in high wheel and tire runout, which will speed up the development of brake roughness, shudder and vibration.

With the weight of the vehicle on the tires, tighten the wheel nuts to 224 Nm (165 lb-ft) in a star/cross pattern.

NOTICE: Make sure to apply a thin coat of anti-seize lubrication only to the interface between the wheel pilot bore and the hub pilot. Do not allow the anti-seize to make contact with the wheel-to-brake disc/drum mounting surface, wheel studs, wheel nuts, brake pads or brake disc friction surfaces or damage to the components may occur.

WARNING: Use only the specified lubricant on the wheel studs as directed in the following procedure. Incorrect lubricant application may result in insufficient wheel nut torque, resulting in possible wheel/tire separation from the vehicle. Failure to follow this instruction may result in serious injury to the vehicle occupant(s).

NOTE: Do not allow oil to build up in the wheel stud threads. Only use 2 to 3 drops of 20 wt oil per wheel hub.

Apply 2 to 3 drops of the specified motor oil to a clean shop towel. Using the shop towel, apply the oil to the wheel stud threads.
Wipe off any excess oil from the wheel stud threads.

 

[esuitt]

165 ft lbs. Really? Wow, I did not know that. And I know they were not that tight coming off.