Gearhead Jim

When our 2009 coupe had about 7k miles, the dealer did the axle nut bulletin- new nuts, Loctite, retorque, sit 24 hrs.

Recently at about 51k miles, I checked them by attempting to tighten. One of them moved at about 60 lb-ft.

So yesterday, a local shop (not the dealer) and I redid them- new nuts again, cleaned all the old Loctite. Had to order the Loctite 272 & solvent, no one had them in stock locally. When we removed the previous nuts, they both came off easily.

This would not have been a good job for the dealer- it took us an hour to get the old Loctite off by using Loctite Chisel solvent + wire brush + metal pick.

So, why did the previous job fail? I don't know, but here are some possibilities:

Loctite was old or wrong grade
Nut and/or axle not degreased
Insufficient torque when installing
Car moved before 24 hour setup time

We did it all correctly, so this time it had better stay together.

Just for grins, the axle nuts needed different size sockets depending on when the nuts were purchased/installed:

2006 factory nuts: 33mm
2006 replacement nuts: 33mm
2009 factory nuts: 34 mm
2009 replacement nuts: one 33mm, one 34mm
2009 latest nuts: 33mm

I've seen several different torque numbers claimed to be in the GM bulletin; 140, 160, 190.

Since our axle had been torqued twice already, and the Loctite should do a good job this time, we used 140 lb-ft. I'll post in the future if they come loose again.

OnPoint

There were enough threads on mine (and room under the center wheel cap) that I used the old nut as a double nut and marked location. They haven't moved since.

AORoads

A long time ago I thought I read of someone else doing the double-nut thing. A good reminder tho, if there's space to do it.

I didn't know the car came with Loctite used on it so possibly the initial cleaning process was less at the dealer. As to the waiting 24 hrs. before moving it (so that the Loctite would set up, I guess), somehow I just can't imagine that happening at/in a dealer's bay. But maybe...

Next report in 2 years!

JoesC5

Mine has held, so far. At 368 miles, my dealer replaced the axle nuts on my 09 Z06 using loctite. Now, 24,000 miles later, no problems.

Gearhead Jim

I'm pretty sure they don't come from the factory with Loctite, the old Loctite we had to remove was from when the dealer did the bulletin at about 7k miles.

They kept my car overnight, but perhaps it got moved inside the building. Or the other possibilities I listed.

VET4LES

Good idea.

GS-Zero

What are the detrimental symptoms that might indicate you need to do this?

Never-Enough

low speed clunk when getting on or off the gas

OnPoint

Yup. The ZR comes with Nord Locks. Which made me scratch my head and wonder why they just didn't put them on all of them.

AORoads

Nord Lock looks like a good solution, but its cost may have been a deterrent to its use on the run of the mill C6.

BTW, what does it cost, and what size is used? Last I read, the regular washers from GM were something like $11.

heli-vette

Loctite can be loosen with a small propane torch or electric heat gun ( industrial hair drier ) . Cut some tin as a heat shield for the wheel . Once you hit about 200 - 250 F on the middle of a nut flat it comes off, at 300 F its liquid . Some use two part epoxy paint as a lock ,you only need to get the inner base threads of the nut and flat washer faces . I notice a clunk when backing up .... as loosened axle nuts .

Gearhead Jim

It's possible to work on the axle nuts with the wheels installed, I've removed the center caps and checked them that way. But it's much more convenient to remove the rear wheels and get easier access to everything.

Jimmy W1

Good idea!!

obxchartercaptain

After reading this thread I went out and checked mine. THEY ARE LOOSE. In fact, the passenger side turned 1/4 turn, with very little effort. I have a 08 Vert purchased NEW. It has 27,000 miles. Is it still covered by warranty? Or am I better off just buying those Nor loc washers and torquing it specs myself?

AORoads

Little bit unclear at least to me. My thinking is it may be part of Powertrain, and that's 5/100K from in-service date. If your car's late '08 production maybe it's still in Powertrain. Even if it's not, dealer may do it under courtesy warranty.

But, knowing what's been written above, seems like if you do it once w. these Nord Locs, it's done. As Victor sez, more costly but.....

Admiral Ballsy

Has this changed very recently? My car (2013) has axle nuts with a..well, I'd call it a collar with tabs that bend down into keyways on the axle end. Never seen anything like them before.

Gearhead Jim

That's interesting, can you post a pic?

Admiral Ballsy

Here are a couple, impromptu cellphone pics:





I can't tell if the slot and the tabs are pre-formed in the nut collar, or if there's some tool that's set over the end of the axle after the nut is tightened, then clocked to the keyway, then punches the tabs out and in.

I am 99% certain that that collar is part of the axle nut, and not some separate piece.

Gearhead Jim

Thanks for the pics!

That looks like a neat setup, and it only took them 7 years to figure it out.

Unfortunately, the older cars like our 2009 don't have the slots in the axle. But the new nuts/Loctite were still good on our 2006 when sold at 44k miles, so I'm reasonably hopeful the latest effort will stay in place.

Admiral Ballsy

I've never seen anything like it before, but this is the first RWD car I've owned with IRS.

I guess there'd be a PN change on the axles whenever they instituted this. Wonder if it's on all models, or only some - do they all use the same axles?