Rear Axle Nut Inspection Recommendation


Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
Just to add to the knowledge database, my car's rear axle nuts are right on the index marks at 13k miles.

Also, control arm bushings and ball joint seals are fine.
 

sahlman

Ford GT Team Alumni
Jul 21, 2011
261
Verona, WI
All good Indy, Ralphie and Specracer. Glad to help a little. Another good topic you have helped your fellow owners on. Look forward to hanging out with you guys next week.

Scott
 
I haven't had any problems with my axle nuts moving, after almost 19,000 miles they are right where they were when the factory put them on and marked them.

However: why don't those of you who have/are having problems with their movement retorque and then punch lock them? You only need to do one spot, it doesn't hurt engaged thread strength and if it's ever necessary to get the nut off, it can be undone by a little shallow drilling.

And by the way: why are the nuts loosening? Is it because 1) they weren't properly torqued to begin with, or 2) there is slop in the axle splines allowing movement? They shouldn't be loosening if properly tightened and there is no movement between the parts.
 
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Howard

GT Owner
Mark IV Lifetime
Apr 26, 2007
1,031
Florida/North Jersey
You guys are such a pain. You raised my level of paranoia, so I pulled both rear wheels to check the paint marks. Both were ok (2006; 10,000 miles). While I was in there I confirmed that the socket for the oil filter can (36mm) fits the suspect wheel nut.

Howard
 
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Indy GT

Yea, I got one...too
Mark IV Lifetime
Jan 14, 2006
2,435
Greenwood, IN
Guys, when BigInch Blake and I were at our last car show, he showed me something disturbing on his GT. The driver side rear axle nut paint stripe did not align. This is a safety critical nut which holds the rear axle assembly together. When the final assembly person torqued these nuts a paint stripe was applied to the nut and to the axle. The theory being that if the two paint stripes maintained alignment, the nut (or bolt as these paint stripes were applied to bolt heads as well) was still properly torqued or tensioned.

It is fairly easy to check this on your car. If you have the optional BBS forged wheels you will need to remove the wheel to gain visual access to the nut, unless you can remove the center cap without removing the wheel. I have the standard wheels and if you remove the chromed triwing plastic cover to gain access to the wheel lug nuts you can see the axle nut and its striping.

While preparing my car for this year’s rally, I inspected my nuts and found a similar situation on the driver side. The two stripes were off by approximately 40 degrees, signifying loosening of the retaining nut. The passenger side was off just slightly and not nearly as much as the driver side. See pictures.DSCN1622.jpgDSCN1624.jpg

I would suggest looking at these nuts on your vehicle. As I stated, this is classified as a safety critical torque and the nuts should be torqued to 400 newton meters plus/minus 30 Nm. Ok, for those CGS challenged 295 ftlbs plus/minus 22 ftlbs. This is a big boy torque. My half inch torque wrench only goes to 150 ftlbs so I had to borrow a much larger three quarter drive wrench to torque the nuts back to spec.

Just an FYI to the ownership.
 

jbyrnes

FORD GT OWNER
Mark II Lifetime
Jun 13, 2006
224
Louisville CO
Thanks for the heads up. Curious what the rough mileage of the two cars are.
 

twobjshelbys

GT Owner
Jul 26, 2010
5,332
Las Vegas, NV
Duplicate...
 
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twobjshelbys

GT Owner
Jul 26, 2010
5,332
Las Vegas, NV
Some one has to say it: I inspected my nuts tonight and can't see what you're talking about.

Can you get in there with one of the mirrors on an old telescoping radio antenna thingie?
 
Someone posted a thread late last March or early in April about this. I checked my wheels at that time (15,800 miles on my car) and they were OK. Once you have removed the wheels or the axle covers in the wheel centers, you shouldn't need anything to see the paint stripes, they are right on the ends of the axles and axle nuts.
 

RALPHIE

GT Owner
Mar 1, 2007
7,279
Bill -

I guess I don't understand the issue of concern regarding the torque level on these nuts. Looking at the design, it would seem that the only thing that they do is hold the half-shaft to the rotor, which are both splined to transmit the power to the rotor and thus the wheel by way of the lug nuts.

It doesn't really have anything to do with holding the rotor to the hub assembly, does it? The front rotors are identical, the only thing missing is a shaft in the empty spline.

While I will agree that one should always check them whenever a rear wheel is pulled (or the cap on the standard wheels), I don't see it as an issue to get particularly worried about. Am I missing something?

Ralphie
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
^^^ +1. Has there been a failure linked to axle nuts backing off?
 

Sinovac

GT Owner
Mark II Lifetime
Jul 18, 2006
5,664
Largo, Florida
Good info. I am surprised neither a hitch clip or cotter pin is used to retain the nut.
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
Watched David (the GT with the trailer) do this at Dearborn. With the forged wheels, just pop the center cap off with a small flat screwdriver. One of the items he keeps in the trailer is the biggest torque wrench I've ever seen.
 

RALPHIE

GT Owner
Mar 1, 2007
7,279
Watched David (the GT with the trailer) do this at Dearborn. With the forged wheels, just pop the center cap off with a small flat screwdriver. One of the items he keeps in the trailer is the biggest torque wrench I've ever seen.
I would recommend an Orangewood stick as opposed to a small screwdriver. Much easier on the surfaces.
 

Simon

GT Owner
Mark II Lifetime
Feb 19, 2013
1,008
Houston
right rear wheel loose...
 
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Indy GT

Yea, I got one...too
Mark IV Lifetime
Jan 14, 2006
2,435
Greenwood, IN
Thanks for the heads up. Curious what the rough mileage of the two cars are.
I probably should have stated I have approx 12K miles on my car, never had any work done on the axles other than Ford replacing the interior axle bolts as part of the TSB and no hard burnout history. The car has been tracked multiple times however I would have thought it logical for the suspension designers to have dialed that into the design.

I am confused by the "two cars are" comment. The nuts pictured in my post are for a singular car, left and right side. Was that not clear?
 

fjpikul

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Jan 4, 2006
10,356
Belleville, IL
OMG, one engineer questioning another?
 

1434gt

GT Owner
Aug 29, 2006
231
is ur car a awd car?
Had the wheels off yesterday and the witness marks on the left rear axle nut were off. The other three corners were fine. Thanks for the heads up on this issue!
 

Derry

GT Owner
Mark II Lifetime
Apr 5, 2006
329
buffalo, NY
Mine were rotated about 90 degrees from where they should be. I wonder if it is related to Whipple and tracking vs normal street use? 6700 miles, third set of tires :)
 

Specracer

GT Owner
Mark IV Lifetime
Nov 28, 2005
6,470
MA
Mine were loose too. I tightened with 1/2 24" breaker bar to the paint pen reference.