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I see a lot of variances with torque specs when a fastener is lubed with anti-seize. Some places say 25% less torque is required for same clamping load, some places say 40% less is required.

I'm rebuilding the chassis on my jeep and have had to cut out about 8 bolts now. When reinstalling bolts I am covering them in anti-seize to avoid future issues during removal. I only recently learned enough about fastener tech to understand that I have been over torquing fasteners for a while now.

What percentage do you other mechanics use in this scenario? My factory service manual doesn't provide wet values so all I have to go off of is what LocTite recommends.

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    I'd think the manufacturer of the anti-seize would know best how their product affects the torque of any fastener, but I'm interested to see the answer here.
    – jscs
    Jun 22, 2015 at 18:56
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    Easy cure? Throw Grade-8 bolts in there, lube them up with your choice of anti-seize, tighten them down, and call it a day. Torque values on these bolts are nowhere near critical to be overly worried about it. Grade-8 bolts will stand up to the stress and will keep the chassis/body bond in place. This is JMHO, so leaving it as a comment.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jun 22, 2015 at 20:39
  • Paulster2 this is actually along the lines of what I was looking for as a comment. All the control arm bolts were upgraded to grade 8. The only problem I have with using LocTite's recommendation is that it takes no account for bolt hardness, thread pitch, shank length, or diameter. It's just a flat ratio across the board. I figured out there some gearhead had developed their own shorthand rule like "<10mm diameter 25% reduction" or something along those lines. At the end of the day I know that I should really use threadlocker here but anti-seize is what i've got.
    – TWood
    Jun 22, 2015 at 20:47
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    You do realize anti-seize and threadlocker have completely different purposes? These are not interchangeable what-so-ever in purpose or in use. If your purpose is to keep things from freezing up, as it seems you do, anti-seize is what you need. ... ... was just thinking, I could explain things on this subject for an hour. If you'd like to discuss over at The Pitstop, I'd gladly oblige.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jun 22, 2015 at 20:59
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    To really answer your question, though, if I'm using anti-seize, I still don't reduce the torque on the fastener. I use the amount specified by the application. The reason being is, in most places where torque is a factor, getting the clamping load even is more important than is the factoring in the amount the lube will reduce the need for torque. If it is that important, you should use a dial indicator to pull a stretch on a bolt, which is far more accurate than anything else. This takes into account all variances in the different fasteners and gets the clamp exact.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jun 22, 2015 at 21:03

4 Answers 4

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If I'm using anti-seize, I still don't reduce the torque on the fastener. I use the amount specified by the application. The reason being is, in most places where torque is a factor, getting the clamping load even is more important than is the factoring in the amount the lube will reduce the need for torque. The anti-seize will work as a lubricant on the threads. You will get a more accurate torque with it than you would with dry hardware. With dry hardware, you can actually be twisting the fastener, which interferes with the overall torque reading (the extra friction caused by the dry threads allows twisting of the hardware and an inaccurate torque reading). Lubricating the threads takes care of this problem, which is what the anti-seize would be helping with.

Even ARP Fasteners agrees that fastener assembly lubricant is important prior to doing your torquing of the fastener. In this video, yes they are advertising their product, but they reiterate pretty much everything I've said.

If it is that important, you should use a dial indicator to pull a stretch on a bolt, which is far more accurate than anything else. This takes into account all variances in the different fasteners and gets the clamp exact.

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  • Is adding assembly lubricant an official SAE procedure? I was of the mind that in today's age, with long-life chroming and other corrosion prevention coatings, there is much less need to add anything.
    – Andyz Smith
    Jun 24, 2015 at 13:42
  • @AndyzSmith - Absolutely not a requirement or official SAE procedure. Adding assembly lubricant can provide better torque values in some situations where it is very critical. Some situations you do not want to add assembly lube where you are torquing the fastener, such as wheel lugs. I don't think long-life coatings would play much of a role in this. My perception is common sense should prevail.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jun 24, 2015 at 15:38
  • I am thinking more along the lines that many people use a lubricant to prevent corrosion, and doing so changes the torque value. The recommendation I heard from a big spark plug manufacturer was that anti-seize was no longer recommended to prevent seizing and they actually don't post a 'wet' value because of this.. Long life plating totally eliminates the problem.
    – Andyz Smith
    Jun 24, 2015 at 17:34
  • @AndyzSmith - I understand. On a side note: whether they advertise using anti-seize on spark plug threads or not, I will still use it there for a few reasons: helps seal the threads against combustion leak; helps maintain greater thermal conductivity; helps maintain greater electrical conductivity. Even if corrosion does not occur, you can still get galling due to the bi-metal aspect, which on aluminum heads, can strip the threads right out of it ... yet another reason to use anti-seize on spark plugs.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jun 24, 2015 at 17:49
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    @Paulster2 I've heard that torque is accounted for in the system as the sum of friction + fastener stretch. So, given a constant target for total torque, if you've reduced the friction w/ lubricant, then you've increased the stretch. Which means that you could cause the fastener to begin to yield.
    – Cognitive Hazard
    Sep 20, 2018 at 3:04
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Although prior answers are indeed correct, the lubricant question is mere pedantry for any fastener that is not critically torqued.

Head bolts (ARP and otherwise) are an obvious exception, but as such these are usually provided with a special lubricant, or clearly stated as a lubricated torque with something like 30W motor oil.

There is no way any chassis component on your Jeep requires critical torquing. Whatever overtorque results from lubrication and torquing to a dry specification can be ignored. You are not going to come anywhere near the elasticity of a Grade 8 fastener. This is not a TTY (torque-to-yield) application.

My feeling is a 25% undertorque might result in improper clamping force, which is far more serious an issue that the "overtorque" resulting from lubrication. That number is far too high anyway, as even a "dry" specification assumes CLEAN and dry.

It's along the same lines as the shadetree parable of never using anti-sieze on wheel studs - 'cuz your wheels will fall off...

To further be a stick-in-the mud, when was the last time you had your torque wrench calibrated? I'm guilty of such things myself. That SnapOn your father bequeathed to you may be a beauty, but I have little doubt that the average torque wrench with some age, and which was sometimes put away under tension, can vary by 10-20% all by itself.

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Angle of turn is the answer. A dry bolt/nut will resist turning (higher torque) giving less grip/clamp a wet bolt nut (less torque) will turn easier. So find /work out the correct angle of turn when grip or clamp is the critical criteria.

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    I think an example would help explain your point more clearly. Could you give an example (preferably with numbers)?
    – Zaid
    Sep 18, 2018 at 12:54
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Depends on the type of anti seize and how much. The key with wet torque is to be consistent with the amount of lubrication. 30% might be a good starting point... But other factors would include how clean the threads are dry... are they damaged? do they have a lot of crud on them?

One way to check is to torque the bolt as you normally would dry then draw a line across the bolt where it meets on the wheel. Take it off then torque that bolt again with lube finding the amount of torque needed to line it up as it was dry.

However I wouldn't advise it. You may have the same clamping force as required by the owners manual. But on a part that rotates/moves/vibrates heavily torque is more important to prevent the bolt from backing out.... I wouldn't gamble with any lube on lugs.

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