anti seize question

[Clem Z.]

Re: anti seize question

some studs are very strong as i heve seen where they pulled the head of the stud thru the axle flange with out breaking the stud while using a air impac wrench so now they use "torque sticks" with air guns to prevent this

[Michael H.]

Re: anti seize question

The answer is: maybe.

I don't have the original prints, but I'd guess the studs were phos and oil and the nuts were zinc coated. If someone can verify that, I'd be glad to give you an expert opinion on the effect of anti-seize. I might even be inspired to do a test.

Michael,

I don't have the prints for any of the studs used for 63-67 but here are the part numbers. Maybe someone else has them?

3775683 63-64 7/16-20 x 1 3/8"

3864028 65-66 7/16-20 x 1 3/4"

3910340 67-69 7/16-20 x 1 3/4"

Below is a new 3910340 for 67-69. I appears to be black plated??

[Bill M.]

Re: anti seize question

Jim,
I agree with you. Long time GM chassis specialist told me lug nuts go on dry. Can be mischief if you lube an application and torque to dry specs.

This is true for the newer cars. The torque spec for the C4 is 100. I would not lube these if new, and very carefully if corroded. I torque my '92 (aluminum wheels) to 80 and have had no trouble (in 15 years) with loose wheels. I felt 100 was just too dam high; one local autocrosser busted his studs torqueing to 100.

I lube the studs on my '59 and '65 (both steel wheels), but tighten by hand to what feels right, just like I've been doing for 48 years; no busted studs, no loose wheels.

[Joe L.]

Re: anti seize question

Michael,

I don't have the prints for any of the studs used for 63-67 but here are the part numbers. Maybe someone else has them?

3775683 63-64 7/16-20 x 1 3/8"

3864028 65-66 7/16-20 x 1 3/4"

3910340 67-69 7/16-20 x 1 3/4"

Below is a new 3910340 for 67-69. I appears to be black plated??

Michael------


I have numerous NOS examples of the 3910340 stud and all are definitely black phosphate-finished. However, they appear to me to be also oiled. I do not know, though, what the finish was for the earlier studs. I expect they were black phosphate, though.

[Michael H.]

Re: anti seize question

Michael------


I have numerous NOS examples of the 3910340 stud and all are definitely black phosphate-finished. However, they appear to me to be also oiled. I do not know, though, what the finish was for the earlier studs. I expect they were black phosphate, though.

Joe,

I also have several boxes of 3910340 but these appear to have had no oil coating. I've had these for several decades though so I suppose the coating may have "gone away".

[Joe M.]

Re: anti seize question

Pick your poison.

The tire guy who cranks the lug nuts down with an air gun set to 135lbs so you can't change a flat tire on the road.

Or a lubricant that, to this point in the discussion, no one has shown what the emperical difference between torque readings would be or at what measured torque/ # of tightening cycles the wheels would fall off.

Can the 'therapeutic efficacy' be so narrow as to cause death 10% outside the recommended lug nut torque range which of course only a very small handful of tire changers even consider? The study population now exceeds tens of millions of cycles conducted by the 'torque oblivious' and no hint of wheels falling off. Lube or not those lugs get abused and their practical lifespan is almost infinite.

What was the deal with the caddy wheels falling off back in the early 80s?
What were the lessons learned form that recall?

This discussion requires a good lawyer, not an engineer. A lawyer will tell us what works and explains our liability.

Lube, baby lube!

[Michael H.]

Re: anti seize question

Pick your poison.

The tire guy who cranks the lug nuts down with an air gun set to 135lbs so you can't change a flat tire on the road.

Or a lubricant that, to this point in the discussion, no one has shown what the emperical difference between torque readings would be or at what measured torque/ # of tightening cycles the wheels would fall off.

Can the 'therapeutic efficacy' be so narrow as to cause death 10% outside the recommended lug nut torque range which of course only a very small handful of tire changers even consider? The study population now exceeds tens of millions of cycles conducted by the 'torque oblivious' and no hint of wheels falling off. Lube or not those lugs get abused and their practical lifespan is almost infinite.

What was the deal with the caddy wheels falling off back in the early 80s?
What were the lessons learned form that recall?

This discussion requires a good lawyer, not an engineer. A lawyer will tell us what works and explains our liability.

Lube, baby lube!

It all started several days ago when Duke said he torqued his lug nuts to 80 ft lbs. on his 63. It's all his fault.

[John H.]

Re: anti seize question

I don't have the stud drawing, but the lug nut drawing (358501) calls out:

GM 4342-M Code 20 Zinc Plated.
Optional Zinc Dichromate Plate 32 Hours Minimum Salt Spray.
Finish to be as taken from plating bath.

[Scott G.]

Re: anti seize question

Over torque on wheel studs can lead to very bad things happening. Twenty five years ago my brother bought a 1967 435 horse couple. He drove it for the first few months he had it without issue. In the fall he was driving the car to put it in storage when the right front wheel came off at freeway speed. Every lug nut had broken. As you can imagine there was significant damage to the car.
He had not had the wheels off of the car since he purchased it. There was no vibration or any indication they were loose prior to the failure.
I believe the previous owner had over tightened the wheels which led to the lug failure. Since this episode, I have replaced the lug bolts on every vintage car I own. I tighten each lug nut dry to the center of the recommended range.

Yup, I agree too. And metal fatigue is another reason why I torque to the minimum torque spec. on 40 year old wheel studs.
Is a fastener that has been torqued to it's stretch range 50 times as durable as a new one that has never been torqued? Absolutely not.
Now add the rust factor. We know that rust has quite an effect on a fastener integrity.
And if the stud/nut is lubricated, that should bring the total torque value down also.

GM clearly states that somewhere between 55-65 ft lbs for my cars is the correct number so that means there's absolutely nothing wrong with 55 ft lbs.

[Ray G.]

Re: anti seize question

They did not drive the vehicle in salt and then have to remove the wheels. As long as the wheels would torque and stay on to get out the door, that is all that was required by them

Hello;
Maybe something wrong. Agree w/ Dick again.
It is not uncommon to use heat to loosen rusted lug nuts in WI.
Consequently SMALL amounts of anti-seize or light oil are common. Especially if one plans to remove the nut & bolts again.
Ray

[Michael H.]

Re: anti seize question

Hello;
Maybe something wrong. Agree w/ Dick again.
It is not uncommon to use heat to loosen rusted lug nuts in WI.
Consequently SMALL amounts of anti-seize or light oil are common. Especially if one plans to remove the nut & bolts again.
Ray

When I lived in the frozen north, with all the salt on the roads, I coated the wheel studs and nuts on my Blazer with SP-350, a cosmoline/parafin rust preventative.

I didn't drive my Corvette in the salt though.

[Duke W.]

Re: anti seize question

Pick your poison.

The tire guy who cranks the lug nuts down with an air gun set to 135lbs so you can't change a flat tire on the road.

Or a lubricant that, to this point in the discussion, no one has shown what the emperical difference between torque readings would be or at what measured torque/ # of tightening cycles the wheels would fall off.

Can the 'therapeutic efficacy' be so narrow as to cause death 10% outside the recommended lug nut torque range which of course only a very small handful of tire changers even consider? The study population now exceeds tens of millions of cycles conducted by the 'torque oblivious' and no hint of wheels falling off. Lube or not those lugs get abused and their practical lifespan is almost infinite.

What was the deal with the caddy wheels falling off back in the early 80s?
What were the lessons learned form that recall?

This discussion requires a good lawyer, not an engineer. A lawyer will tell us what works and explains our liability.

Lube, baby lube!

Good points! I think a lot more damage can be done because some grease monkey waaaaaaaaay overtorqued the lug nuts with an impact gun.

80 lb-ft is not a lot of torque on a 7/16-20 stud with a high heat treat, and I doubt if it even loads the material to half the yield strength. Fatigue is not an issue since the studs aren't really cyclically loaded.

Beyond the above and my previous reasons for using anti-seize on lug nuts you guys are WAAAAAAAAAAAAAAAAY to anal over this subject.

Duke

[Michael H.]

Re: anti seize question

80 lb-ft is not a lot of torque on a 7/16-20 stud with a high heat treat,
Duke

Chevrolet thought it was, at least for 63 through 66.

[Duke W.]

Re: anti seize question

Not necessarily. The Chevrolet torque range is to insure that the wheel studs have sufficient clamping force.

They also knew that overtorquing wheel nuts in the field is common, so the stud is probably bigger than necessary to take the abuse.

BTW, five lug wheels should be torqued in a "star pattern". That mean that starting with the first nut, you proceed to every other nut until you count five clicks of the torque wrench.

Duke

[Michael H.]

Re: anti seize question

Not necessarily. The Chevrolet torque range is to insure that the wheel studs have sufficient clamping force.

Duke

So, you're saying that when engineering said 55-65, they really meant 80.