Halfshaft Bolt Failures and Customer Satisfaction Program


Accufab

Well-known member
Mar 14, 2006
142
Rear axle bolts

Sorry, haven't been on this site for awhile. I read all the posts on the rear axle bolt issues that many of your seem to be experiencing. I would have responded on one of those threads but they were locked or closed. Anyway, we have sold over 200 rear axle bolt kits to date. We have never experienced a single failure with one of our bolts. And this includes several cars with HP levels between 850 and 1100 rear wheel horsepower. Just thought that you should know.
 
Aug 25, 2006
4,436
Sorry, haven't been on this site for awhile. I read all the posts on the rear axle bolt issues that many of your seem to be experiencing. I would have responded on one of those threads but they were locked or closed. Anyway, we have sold over 200 rear axle bolt kits to date. We have never experienced a single failure with one of our bolts. And this includes several cars with HP levels between 850 and 1100 rear wheel horsepower. Just thought that you should know.
This is a very timely and well received post

I have installed numeous sets of the AccuFab halfshaft hardware and continue to do so with no failures not to mention the fact that I like the head design of the ARP hardware much better than the OEM style. I share this even though I have presently in my facility no less than 4 sets of Ford's latest halfshaft hardware.

My position remains as follows and as I share with all of my customers; I respect and truly appreciate that Ford brought to "ALL" the new version of the halfshaft hardware through a campain process however considering that this is at least their 3rd attempt I will not subject my gal or those of another to a product with a yet to be determined track record. Instead what I have and am doing is giving each person the latest Ford halfshaft hardware kit for them to keep as a back up should there ever be a failure with the AccuFab hardware which I suspect is remote.

Now after we go through a full season of activities with these gals that have the latest halfshaft hardware installed my feelings may change however for now the only halfshaft hardware that I install is AccuFab's.

FYI: I have no ties to AccuFab other than I use their products.

All the best

Shadowman
 

Accufab

Well-known member
Mar 14, 2006
142
Appreciate the testimonial, Shadowman. To be honest, Accufab wasn't interested in getting into the bolt business. This was also true about other Accufab products for the GT (the air inlet support and the coolant hose supports). We wound up backing into offering these products only because customers were having problems in these areas, and we had enough GT dyno time to witness these problems for ourselves. None of the fixes were any rocket science. We saw a problem and created a solution, no big deal really. Isn't that what hot rodders have been doing for the last 50 years? In my opinion, there was no reason why Ford couldn't have done the same thing, and in a timely manner. Why they didn't is a mystery to us here at Accufab.
 
Aug 25, 2006
4,436
Appreciate the testimonial, Shadowman. To be honest, Accufab wasn't interested in getting into the bolt business. This was also true about other Accufab products for the GT (the air inlet support and the coolant hose supports). We wound up backing into offering these products only because customers were having problems in these areas, and we had enough GT dyno time to witness these problems for ourselves. None of the fixes were any rocket science. We saw a problem and created a solution, no big deal really. Isn't that what hot rodders have been doing for the last 50 years? In my opinion, there was no reason why Ford couldn't have done the same thing, and in a timely manner. Why they didn't is a mystery to us here at Accufab.

You are welcome

Now to the "why" regarding Ford I can only speculate as such I will not chime in other than to say "Thank You Ford" for continuing the quest for the final solution however to my feelings about the hardware as presented by you and your team I will share the following;

Once I install your hardware system on my own gal the peace of mind alone was worth far more than the price of admission. Then add to this evey time I have installed your hardware system on another's I always consider the project finished rather than pending as such the secondary peace of mind is even greater.

Keep up the great work

Takes care

Shadowman
 

DBK

The Favor Factory™
Staff member
Le Mans 2010 Supporter
Jul 30, 2005
14,663
Metro Detroit
I have the Accufab bolts and will not be changing them out for the new ones. As stated, I have never heard of a single bolt breaking.
 

06fordgt

GT
Mark II Lifetime
Le Mans 2010 Supporter
Nov 8, 2006
1,830
Toronto Canada
Rec'd my letter from Ford Canada. Interesting to note the letter only refers to 2006 cars not 2005 cars.
Besides some minor layout and format differences from what I've seen posted here the other real difference is the Ford "Customer Relationship Centre" and phone number 1 800 565 3673.
Since I've already had the failutre and used the Accufab fix, I wll now attempt to get the refund for the work done.
 

MAD IN NC

Proud Owner/ BOD blah bla
Mark IV Lifetime
Feb 14, 2006
4,174
North Carolina
GET YOUR NUTS AND BOLT's CHECKED! Program 07B49

Just got back from the dealership where they changed by halfshaft bolts! Thanks for this dealership and the work Coy (service writer) and Grahm (mechanic) just did being at Don Jenkins in Fuquay Varina NC.

SCARY:eek ~15 months ago for peace of mind I had them replaced. At that time the "shiny" original washers were cupped and failure was possible.

Today when I looked at them the washers were they gray type - not cupped but one bolt head on the passenger side broke off just by putting the socket and allen on it!. Two others broke off during de-install and only one came out without the head shearing off. I'M GLAD I WENT TODAY! I was destined to be road kill!

The first picture is the old passenger side. The bottom "washer" is the Loctite between the washer and the halfshaft itself. file = pass

The last picture is the new washers and bolts! file = new

The old "original" washers were 6.05 mm thick. The new 07B49 washers are 13.5MM thick with two insets of ~6.45MM for the bolts. My insurance set of Accufabs are 7.6MM thick (Anybody want to buy a set of new Accufab bolts? - just kidding. I will keep them as I have not heard they have ever failed yet).

So - RUN, don't walk! Get them bolts changed! It's worth the 4 hr's.

Thanks Jamal!
 

Attachments

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
3,602
Ford's Latest Halfshaft Repair vs Accufab

Well, today was "Ford GT Halfshaft Bolt Upgrade Day" for Ryan and I. George invited us over to perform the Accufab upgrade on both of his fine machines. This was approximately the 19th & 20th upgrade we have done and it was a good workout as we rolled each car back and forth to get access to each of the outer bolts. (We realize how spoiled we are to have the lift back at home!) It took us about 3 hours to get both cars done and on the way home, I got a call from my local dealer informing me that my Ford upgrade had come in.

We drove over and picked up the kit and I took some pictures of the latest Ford Kit compared to an Accufab kit. I believe Forum members may be interested in seeing the differences.... and perhaps even my opinion(s).

Both the accufab and Ford kit now provide the (6) outer flange bolts. why ford did not include these in their first kit remains a mystery to me, but kudos to Ford for doing it right this time around. The Ford kit includes a new set of the exact same, T-50 TORX outer bolts that you will remove per side. The Accufab kit includes some very pretty ARP 12-pt bolts that are also drilled for thse that would prefer to wire them. (Unnecessary, in my opinion.) The outer bolts have never been an issue so I didn't bother with any pictures.

This first picture is the Accufab Kit inner washer and bolts (on the left) and the Ford inner washer and bolts (on the right).



There's a big difference in the thickness of the washer as depicted in the following pictures. The new Ford washer is much thicker and has been recessed to allow the inner bolts to drop in. The recess is necessary because the top of the bolts even in the original set-up almost come into contact with the dust cap of the CV joint at the end of the halfshaft.







What was REALLY interesting for me is that the new Ford washers are the exact diameter as the Accufab's - which are significantly larger than both of Ford's previous washers. In a one-on-one conversation with a rep from Ford, I know that they were originally "concerned" about the diameter of the Accufab washers, so I'm glad to see that there must now be agreement!





Here's a comparison of the inner bolts. The ARP bolts in the Accufab kit are still the best, IMO.







The Ford kit looks real good and I assume it will resolve the problems we have been having. I still prefer the Accufab kit because I believe the bolts are still superior. I have not and still do not believe that the embrittlement theory is the full explanation and there are very complex forces acting on the bolts. The stronger bolts supplied in both kits may be enough to withstand these forces, but I'm going to opt for the best bolt manufacturer in the world - which is ARP.
 

Indy GT

Yea, I got one...too
Mark IV Lifetime
Jan 14, 2006
2,403
Greenwood, IN
Great Pictures!

Kendall-
Great post and thanks for the comparative hardware pictures of both kits! Your attention to detail and observations are what make this Forum a great clearing house of information.
I agree with you both kits will solve the previous bolt breaking problem and that ARP is in my opinion (also) the best source of premium fasteners. Whichever route an owner opts for, the issue will go away.

I do have to comment on your statement, "I have not and still do not believe that the embrittlement theory is the full explanation and there are very complex forces acting on the bolts. The stronger bolts supplied in both kits may be enough to withstand these forces, but I'm going to opt for the best bolt manufacturer in the world - which is ARP." Ok, what do YOU think is the failure mode of the bolt?

I am told by reliable internal sources, many of the warrantied failed bolts which were returned to Ford engineering were carefully metallurgically examined. It is pretty easy to see the "beach marks" on the fractrue surface indicating a fatigue failure but what neucleates the crack origin? Because of the failure publicity (and the first fix not correcting the problem) the team inspected every aspect of what failure mode was breaking the bolt. A lengthy and time consuming process but one, given the gravity of the situation, was necessary. Obviously this entailed insitu strain gauge testing of the bolts during an agressive driving cycle. Thus the "complex forces acting on the bolts" was fully characterized and I'm told the maximum loading was nowhere (let me repeat, NOWHERE) close to the bolt tensile strength of an M8 bolt. Thus this is not a bolt STRENGTH issue.

I realize this is the "easiest" explaination for laypeople to grasp because most all of us have an idea of how things break when they are overloaded. Higher order failures like fatigue, metallurigical defects, hydrogen embrittlement, residual machining surface stress, hard alpha inclusions, etc. are difficult to understand and best left to the engineers to sort out.

Again, Kendall, I appreciate your comments! I am just glad all owners have two good options to fix our cars and remove the fear of an on-the-road half shaft bolt failue.
 

Indy GT

Yea, I got one...too
Mark IV Lifetime
Jan 14, 2006
2,403
Greenwood, IN
Paul,
Good question. I will volunteer my thoughts although I am not so sure of the design evolution of the washer as I am about the bolts.

The early (I believe silver in color) washers were noted to have a perminent cup or "set" when the team started looking at the returned failed hardware. This was unexpected. I summarize hardness tests led to the conclusion the washers were not properly heat treated (increases washer strength), bent or cupped under initial bolt load during the torquing procedure and led to subsequent bolt load relaxation.

Typical bolted flange design is to specify as high a bolt preload as possible (within the material limits of the bolt but usually 90% of TYS, although some fasteners are torque-to-yield which thus exceed TYS) with the objective to never allow the bolt load to relax. Flanges with little or no preload are predisposed to failure with the flange sustaining anything more than a constant load. Consideration must also be given to the relative stiffnesses of the mating flanges and considerations for thermal expansion. This drove the early focus to an inferior washer. Thus the first fix was a stronger (heat treated) washer and the same bolts. Obviously as failures continued, this was not the correct answer and the team went back-to-the-drawing board to actually determine the "root cause" of the failure. This is what takes TIME.

The installed bolt head clearance with the CV is minimal and though not shown in Kendall's pictures I belive the ARP bolt heads (from the bolt bearing surface to the top of the head) are slightly longer than the OEM bolts. I believe the clearance is important to maintain and thus the OEM kit counter-sinks the bolts into a new even thicker and stronger washer to maintain clearance. It is my guess that a "new" washer design was already under way when the second evolution black unit washer was found to again be failing bolts. The team did their due dilligence, determined the hydrogen embrittlement problem with the bolt, sourced a new bolt to remove the problem and went with the third generation thick washer even though the bolt (not the washer) was found to be the root cause.

At least that's what I think happened. (And I do not work for Ford, thus just opining.)
 

Indy GT

Yea, I got one...too
Mark IV Lifetime
Jan 14, 2006
2,403
Greenwood, IN
Part Number Requested

Latest ("CA" configuration) and final Ford axle bolt kit upgrade -
Part Number 4G7Z-4B490-A

This is the one you want to get installed.

Earlier Ford replacement kit ("BA" configuration) will not fix the bolt problem as it uses the same electroplated bolts (internal hex wrenching) as OEM supplied by Riccardo in the transaxle.
 

DWR46

GT owner
Mark II Lifetime
Feb 20, 2008
112
Ford's Oasis computer report will show if the recall was performed by a Ford dealer, and also will show if the car owner chose to just receive the recall bolt kit and then have the installatin done elsewhere. So the Ford computer will definitely tell you if a recall kit has been issued for a specific ar.
 

TEXAS GT

2006 Twin Turbo
Mark IV Lifetime
Le Mans 2010 Supporter
Any Ford dealer should be able to pull up the records by your VIN number. If they were replaced by a Ford dealer, it will show up.

If the Accufab bolts were installed by the previous owner, only he will know. Try to locate and contact him.

Short of that, I believe the only way to find out for sure would be to remove the coupling and visually inspect the bolts themselves.

Whatever you have to do, it's worth it to know. The original bolts MUST be replaced.
 

Indy GT

Yea, I got one...too
Mark IV Lifetime
Jan 14, 2006
2,403
Greenwood, IN
Search

This topic has been discussed to death. Please use the search function of the Forum.

Both bolt options provide a suitable alternative. Entirely up to the individual owner.
 

thegtguy

*Supporting Vendor* GT Owner
Supporting Vendor
Apr 20, 2006
485
MI
Half shaft bolts

I really hate to bring this up again but as many of you know we have been assisting many owners with this. Most with installations and others with the parts. I was just informed today from the dealer that we deal with that the program expired as of Jan.1, 2009. Now owners will have to pay to get the parts and or work done. Hopefully everyone has had this done already and it doesn't matter. Just wanted to let everyone know.

Rich
 

B O N Y

MODERATOR & FGT OWNER
Mark IV Lifetime
Sep 5, 2005
12,110
Fresno, Ca.
seems fair, when did they stop making the FGT?
 

MAD IN NC

Proud Owner/ BOD blah bla
Mark IV Lifetime
Feb 14, 2006
4,174
North Carolina
they quit makingthe FGT? :eek















:rofl Sorry -couldn't resit
 

B O N Y

MODERATOR & FGT OWNER
Mark IV Lifetime
Sep 5, 2005
12,110
Fresno, Ca.
Mike,
I am taking deposits for the 2010 model.
Please wire transfer $25k
Best regards,
Bernie Madoff
(bony let me use his account)
 

fjpikul

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Jan 4, 2006
10,151
Belleville, IL
I don't have my recall letter with me, but I thought there was no time limit? Will check when I get home this weekend. Or maybe it was no mileage limitation?
 

Sinovac

GT Owner
Mark II Lifetime
Jul 18, 2006
5,585
Largo, Florida
I believe my letter from Ford referenced the deadline. Keep in mind it wasn't a "recall".