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The topic of axle nuts has been addressed a few times and I always input a few facts and have no intention of posting beyond this or getting into a pissing match.

When my car was a 471rwhp 4.10 geared car, I broke a 1/2 shaft at the hub spindle after a tuner tightened my axle nuts to 160ft lbs. I had driven the car for thousands of miles and the day he did this it broke....same day. He did say that the nut was at 80ft pounds. They replaced the 1/2 shaft and that one broke the same day again. 160ft pounds.....I was stranded 130 miles (10pm at night on Saturday) from home and a forum member (AINTQIK) was nearby and he told me to tow to his house and he took his 1/2 shaft off his car so I could get home. Being intelligent and having discussed the issue, we decided to install the nut and mark the shaft and nut with a black marker but TQ'ed to 100ft lbs. I drove home.

I ordered him a new shaft and a new one for me to have as a spare.

Two weeks later I removed the wheel to check the nut which was TQ'ed to 100ft pounds. The nut didnt move based on the marks it had on its from the marker. I check with the snap on TQ wrench and it was 80 ft lbs. Why? The spindle stretched. If I retightened the nut, it would be tightening it down on a stretched spindle. 70 or 80 or 90 ft lbs wont be going anywhere. If there was no nut at all it would still function and the 1/2 shaft cant 'fall off'.

So I chose to install the new 1/2 shaft and apply lock-tite and tighten it to 100ft lbs and never again adjusted it. The car is now near 800rwhp and the same 1/2 shaft is in place and when I check the nut, i do so with my fingers to see if its loose and falling off. If its at 55ft lbs from a stretched spindle, it wont stretch more and wont break from re-tightening it.

I dont want to test with a TQ wrench since it would require a break of the lock-tite's grip and would only serve to stretch the spindle leading to a break.

Dont fix what isnt broken. Dont adjust what isnt falling off. If there was no nut you still couldnt get that shaft off the car so dont worry about it being 55-70-80- or any value if its not falling off. If it did come loose its more likely from the spindle being stretched and re-torqing will only pul more stress on a weakened spindle.

Do with this ionfo what you want.

 

Spin Monster - you make very good points here. I too think that 160 ft-lbs is too much. I checked my 06Z06 a year and half ago and found both sides essentially at 120 ft-lbs. I worked my way up from 60 ft-lbs to 120 in 10 ft-lb increments. One nut did slightly move finally at 120. Now at about 20k miles later, I still have both at 120 ft-lbs. No new nuts or lock-tite on either.

Two weeks ago I checked my son's 08 coupe at 7k miles. Same incremental procedure since I was checking his car for the first time. One nut was at 120 ft-lbs. The other was somewhat below 60 ft-lbs. I frankly believe that both cars will now stay at 120 but I will check every year or so.

 

If one breaks, I would go with WHT's fix here on the new shaft but 160 is just rediculous. The wheels dont fall off at 90 to 100ft lbs so why would the nut? Checking the TQ with a TQ wrench is what breaks them so dont check after the new install. If the car is under 120 and you tighten it back to 120 you are only pulling along the spindle harder and its pulling on a stretched spindle. Who cares if its at 60ft lbs. If it isnt loose with fingers, its fine. If the nut falls off it wont cause an accident. The shaft cant come off. Whats really funny is that the shaft doesnt want to come out when you drop the suspension to intentionally take it out.

I think the point thats missed is that the GM theory is to get it so tight that it wont back off but in reality the nut inst coming loose; it didnt turn at all. It was a stretched spindle. Remember that failures on a car is what we count, not cars that didnt fail yet. Just because someone went thousands of miles without breaking doesnt mean its ok to do that. The number of failures will rise when the wrong thing is performed so we count the number of failures. A preceedure that has 3 failures for 100 cars is bad but we dont ask the 97 owners that didnt have a failure, we ask the 3 that did. What you want is a proceedure good for the 3 cars that failed. 30 in 1000 cars is the same failure rate and 300 failures in 10,000 cars is too. Tq to 100 with lock-tite and you wont fail. No one broke a shaft or had a break down from not changing the 60lb tq value from any car. Dont touch it.

 

A bit of drama on your part.

Given the choice between a broken shaft from the nut being re-torqued and a nut at 60ft lbs that doenst break, I'll take the 60ft lbs. I have never once heard of an accident from not touching it and it backed off completely and fell off the axle. A broken axle on the other hand can seize the wheel. If you disagree with the philosophy, fine. I didnt post for a pissing match with you. I figured people would read what factually happend tome and make a decision with what they should do.

It was a good post you made. I get critiqued all the time. I lost count how many times Glass Slipped popped in to clarify info in my threads and he was right. You post and take criticism to refine the post, not get all bent because someone didnt have info that agreed with all your points. Doing what you did here will break axles. Dont go around the car and tighten bolts that arent falling off if the bolts isnt loose from turning and you are dead wrong about the spindle not stretching.....a black marker proved that about 2 years ago. A stretched spindle will loosen the bolt even wth your fix and the stretched spindle will again stretch if re-torqued. The nut wont turn with lock-tite and if the TQ value went down on a loc-tited nut, it shouldnt be tightened

 

Great info SM. That's one thing that seems to keep happening with people; we want a dead set "something" a number, an action, anything so we can stop worrying over things. Torque from new is one thing. Torque after wear is another. Variables happen.
Harley copied GM with their head bolts and maybe studs, in the Evo. Once unbolted for maintenance, they were to be tossed and new ones used. They borroed the idea from GM. The metal was aligned in some fashion so that when torqued to spec, another 1/4 turn was given to set them properly. That caused the metal in the bolts to lock and to remain pliable for that engine regardless of heat and cold. Many failed to comply with Harley's requirement when boring their jugs or other maintenance and then snapped those same headbolts upon torquing them down again. Once set, they were not to be touched. The torque was only good on a new set of bolts, not on a reused set. Engineers do things for a reason, just never tell us.

 

 

100% false. Please elaborate on your proof.

Telling someone to tq a stretched spindle to 118 is dangerous. Your repeaded assumption that the nut works loose has been proven to not be true as a new axle with zero miles and a nut marked with a marker as well as a used axles with the nut marked the same way on multiple cars shows absolutely no movement between the nut and axle (even when the TQ value drops); thus the looser nut with no nut movement is caused by a stretched spindle or possible by a compressed hub.

I have tested it on so many cars and had the customer look at the marker marks on the nut and axle and havent heard of a single person seeing the nut change position. If its 60lbs with the nut never having moved you are TQ'ing a stetched spindle. Tq'ing it more stretches it more.

A broken axle can kill someone.

 

Here is a interesting read on axle nuts and the specs for them.

http://vsmus-origin.skf.com/Files/Br...PDF/457377.pdf

It was the single most resource I could find with a wide range of applications. Some of you have worked on simular cars and trucks can tell the difference in axle sizes.

A cv joint is not friction-less moving part. As it goes in to compression it pushes out and when it goes into extend it pulls on the "nut and bolt" like talked about above. This movement is very hard on "nuts and bolts" in all shapes and forms. The nor-lock style washers (deleted) have proven themselves to remain tight under these types of Nut and bolt stress. I don't think you will need to recheck as often as you may think.

I agree it would be interesting to see the difference in actual stretch between 100-160. With the large washer like nut, "pitch" nut and being dry. The amount of friction is pretty great in this application. Then stress the "bolt" with heat and vibration and check again. The overall length of the "bolt" would be a better look into the cause, at some point the nut and threads start to pull pretty good also.

Why does that left side always seem to be the issue
http://en.wikipedia.org/wiki/Precession_(mechanical)


There shouldnt be a stretch issue in this style "bolt". But if there is, all bets are off and good luck to all.

Randy

 

Deleting your post takes my misinfo off the net.

I wish you would prove some of these things you're saying.

I have yet to see a single axle break that was under the TQ spec and I would really love for you to explain why two axles installed by Cartek on my car broke after being installed to GM's specs.

If you would just include your wisdom on these issues, I'm sure many people would feel safer about trusting in your views here that were tested on a single stock power level car. My tests show a nut that didnt move.

I think everyone has had enough input on this non-sense and can make an educated decision and file it where it belongs.

 

http://forums.corvetteforum.com/c6-c...-nut-fix2.html

I don't know why a new thread was started and the info deleted from this one. No need to hide anything. If the info is accurate and the OP believes in it, post it with an explanation and proof. We all just want to learn.

 

GM released five different versions of the C6 axle shaft before getting to what became a final version. Most of the axle breakage occurred with the first two part numbers. The third version was PN-15891870

Since March 2006 I've made about 50 visits to the drag strip with a fairly wide assortment of C6 models, base, Z51, Z06, ZR1. They made a couple thousand passes while I've watched.

We always start the day by cleaning up clutch fluid and tightening loose axle nuts. We use the Chev current spec of 160. Once set to 160, most of the cars haven't re-experienced the axle nut loosening. Not a single car among this broad sample has broken an axle except with three with the very early PN axles.

Again the breakage of axles has highest incidence among the first two versions released and installed on 2005s and 2006s. By the time the 2007s came out GM had the third and fourth versions. Those, along with the fifth, have been very stout, absent the classic driver errors that provoke breakage.

Here is a good thread on the evolution of the C6 axle shaft breakage.

Here is the GM doc that many of us have followed without further issue.

I did the locktite-blue to my axle nuts in early 2007. Now, about 140 drag strip passes later, they are still at nominal spec. And my axles are original 2d iteration versions, not the stronger later one. Yet, they remain unscathed at 192 passes.

Finally, the first questions to ask when someone breaks a C6 axle are
(1) What year is the car and is the axle shaft original? If it's not, what's the PN. If it's not PN 15891870 or later, then the part was likely the principal issue.
(2) What was the car doing at the moment the axle broke? Odds are high the car was being subjected to one of the classic driver errors laid out at the link above.

Ranger

 

Good summary, Ranger, and thanks for the info!

 

My car is a 2009 Coupe, so it should have the latest version of whatever GM is putting on the base cars. Which may be different from the Z.

I think Spin would recommend against the GM Loctite/160 fix and Ranger would recommend it; any comments from those guys?

 

Cartek replaced the first broken axle with a C5 axle. The third was also a C5 axle and installed to 100ft lbs with red loc-tite. My car is over 700rwhp and its been on the car for 2 years with no issue. The marked lines for the nut/axle havent moved so there is no need to take a chance on tightening.

To date, I have never once launched my car, IE no clutch drops ever. I have never done a burn-out off the line ever. The first axle broke in a parking lot on a 1-2 shift at 5mph. The second broke in 2nd gear the night I got the car back from Cartek with the C5 axle. The last axle is a C5 part again but with 700+rwhp and has withstood Mickey Thompson ET streets. I posted the info to share an experience and give a data point. Do with it what you want.

 

Recommend the procedure I have followed on many C6s that I've raced with at the track and on road courses. I have torqued the axle nuts to the current GM spe [see post 16 above]. None I've set to that spec has broken an axle. Beginning with MY 2007, the factory axle shaft issue for stock and near-stock Corvettes was solved. Very few driver of 2007s broke axles. And I'd suspect driver error on those incidents.

So, my recommendation is to follow the GM spec. No need to use Loctite unless they come loose. Once set to 160, they usually stay there. If you are launching the car or running sticky tires or those with a big contact patch, suggest checking the axles nuts before events.

Finally. GM has the warranty burden for its cars, Owners on the CF did a lot of data capture on issues of axles and axles nuts that was helpful in assisting the issues to be resolved.

That's my take. Opinions vary.

Ranger

 

You are entitled to your opinion but a single 460rwhp car isnt going to give a valid cross section of what happens if 1000 cars do it. GM has been wrong on a number of occasions including the balancer nut, the top delamination and the use of a seriously weak diff in the 2005 model year for which they would not fix with a newer diff when cars broke under warranty.

My car did fail with the current GM spec and your car not failing doesnt mean its ok. As already said in the thread, we count the number of failures to set a statistic for failure rates. I have 2 failed at 160ft lbs and the C5 axles are the strongest ones there are as proven by 8 second runs. Before dismissing anything one should seriously discuss why mine failed before you do to yur car what was done to mine for the axles that failed.....logical?

On a side note, I thought the current fix with GM was to use loc-tite. I could be wrong.

I have the current set-up at 700rwhp for 2 years. It works for my power level with Mickey Thompsons and 4.10's gears. I'ds say it works then for pretty much what everyone will use on the street.

 

Using words like spew and such is bordering on disrespect. Until now you have pretty much kept it professional and I'd like you to keep it there. I am not being disrepectful to you. I am standing by my position and its ok for us to disagree.

As I previously stated your fix would be great for a new axle but I advise against reTQing as a periodic thing. I also agree with the lower TQ value. Your reason for using the lock washer is to be able to check with a TQ wrench as to the current TQ value and verifying TQ value of a nut that is still for any time will take far more TQ to get it going and this isnt a valid way of checking how tight a bolt is. You have to loosen it and keep it moving up to its desired TQ setting. This is why the loc-tite is a valid fix.

It would be best to check the nut's position with a painted mark on the nut to axle relationship. If its the same, dont touch it. If the TQ value moved and the nut is in the same position to the axles markings then if its loose its because of a different reason than the nut moving and you fix wouldnt do anything. Loc-tite is valid and checking a frozen nut with a TQ wrench is not.

When this topic came up there were others who posted pics of the axle breaks they had when they retorqued the bolt. I wasnt the only failure and back then, some of the breaks were from guys who simply retorqued to the old 118' lb GM spec as you suggest doing. They broke also at the base of the spindle and not at the center part thats thinner on the early C6's.

You have no proof that the retorqing isnt what is breaking them. It is. I never once saw in any of those threads a single person reporting a base spindle break unless they retorqued.

This thread was posted by a guy who stated that he re-torqued the nuts regularly and thinks that the one time he didnt do it was why it broke. He kept TQ'ing it to a point it broke. Has anyone ever reported a break that didnt continually TQ it?

http://forums.corvetteforum.com/c6-z...ut-torque.html

My second axle was at 160ft lbs for about 90 miles and broke. Did it break because it was too loose?

 

I think it's important to realize that you are confusing causation with correlation. Your car did fail with the current GM spec, but we can't be positive that it failed because of the GM spec. The two things are correlated, but we have no direct evidence of causation.

You could have been unlucky and gotten a couple of defective parts, there could have been issues with installation, the extra power your car makes could be a contributor, who knows.

Just because one person had failures while using the GM spec, doesn't mean that everyone will. Without more evidence it makes the most sense to follow GM's guidelines, especially considering the number of people on the forums who have not had any problems with GM's specs.

 

I've tightened the axle nuts on about 100 C6s at the tracks I visit. Pretty decent sample. Did several more today. Identical results. No breakage. None came loose again after making drag radial launches. They need periodic checking but the results remain encouraging.

One ZR1 whose axle nuts I tightened to Chevy spec in April, was still at Chevy spec in Mid-October despite about 40 intervening passes running fast times.

Ranger