Halfshaft Bolt Answers (all threads merged)

[Gimbal]

This past week, one of my clients and a good friend popped in from Europe for a quick visit. He is one of premier racing engineers in the business. For decades he has worked in Formula 1 and beyond. This a famous man and out of respect, I don't want to name him, because he is doing a favor off the record for me, but trust me, you know who he is. He didn't have much time, but we did look over everything on this post about this problem while he was in my office. He asked for more info, specifically, schematic drawings of the design on the transaxle and photographs. Could someone please send me these if you have them? I remember some photographs of the inside of the transaxle where the problem originates being posted I had thought, but I can’t find them (please don’t refer me to do a search on the forum). And one of you engineers out there, please send me a brief synopsis of the problem in proper engineering language along with one in simple English. Gimbal, Jay, Kendall, please anyone…? It's racing season for him, so he is incredibly busy. I need the right information in a concise package that I can email to him so we don't waste his valuable time. I want to make sure we take the best shot at this. In addition, he is personal friends with the chief designer at Ricardo (actually he joked about giving me his personal cell phone number so I could ask him how to fix it). I am not promising anything, but it's a rare chance to have what many people would say is one of the top racing engineers in the world take a glance at the situation and render his opinion. And with his connections, who knows?

Send it to: gulf_gt@att.net

Hi GulfGT, Good to hear you have such a good contact. I think going thru this forum on the axle problem is a good step on understanding the problem and getting some feedback on ideas and such. It doesn't seem to be the best place to get solid information such as drawings, specs or details. Those things are probably difficult to get anyway unless someone has direct inside connections. The root problem has to be the loose fitting spline especially in the "rocking" direction and not so much in the "rotation" direction. The real fix in my opinion is a new tighter fitting flange spline. Temporary improvements might be better bolts and washers. Until someone capable can make a better fitting flange spline we all have rotating time bomb axles. The problem is there is not an easy way of making a new flange that will work for all axles. It might be easy enough to make two tight fitting flanges for one GT, but to come up with a global fix is tougher. If there were enough room for a special flange that could actually be tightened or clamped to the axle that might work but there is just no room especially since the seal surface is integral to the flange.
I have some photographs, drawings and video of the flange rocking and could send you if that might help, just let me know.

 

[Gulf GT]

I have some photographs, drawings and video of the flange rocking and could send you if that might help, just let me know.

Please, please, please. I am pretty sure it was your photographs I saw sometime back. On the drawings, just the ones you did without the modifications. We were looking at your drawings, but many had the suggested mods. He wanted to see one without any mods, just stock.

gulf_gt@att.net

David

 

[dbk]

Word on the street is there are currently 4 setups undergoing testing with both sets of washers...

 

[Cobrar]

Word on the street is there are currently 4 setups undergoing testing with both sets of washers...

Great News! :banana Hope it gets to us soon! :banana

 

[standj]

Axle Shafts

Has anyone had the repair done to correct the issues with axle shaft failures?

John

 

[HHGT]

We use Sugar Free Dentyne Gum. Only works with the Cinammon flavor though!

 

[SteveA]

There are 61 pages to read on this subject in the Tech forum. Don't plan on doing anything for the next few days.:lol

 

[standj]

I will start chewing, one stick per bolt?

 

[standj]

Thanks Steve

 

[HHGT]

I will start chewing, one stick per bolt?

I was messing with you - However, like Steve said this issue has been talked about in length. BTW, I would read the thread starting w/ the latest posts and go backwards.

:cheers

 

[standj]

I know!!
Thanks
John

 

[Gimbal]

Please, please, please. I am pretty sure it was your photographs I saw sometime back. On the drawings, just the ones you did without the modifications. We were looking at your drawings, but many had the suggested mods. He wanted to see one without any mods, just stock.

gulf_gt@att.net

David

Hi GulfGT, sorry for not getting back sooner. Just sold my company and pretty much worn out! Tired of reading legal documents but starting to get back on track now.

Check out my post #497 it shows the stock configuration with the idea of just adding the two extra bolts. If you need anything else just let me know.
Thanks,
Gimbal

 

[JAM-GT]

Another GT goes down

I don't know if anyone is still keeping track of half-shaft failures, but my GT (2005 #1498, 2400 miles) just died this morning. I had just pulled on to Interstate 90 in Seattle and was going about 70 miles per hour. All of a sudden, I noticed that the RPM's had gone up and it felt like I was decelerating. There were no unusual noises. I first thought that I had accidently put the car in neutral, but that was not the case. I managed to coast over to the emergency lane on the bridge over Lake Washington. When I took a peek into the engine bay I could see the exposed splines of the half shaft, so I was pretty sure that I knew what just happened. Ford Roadside Assistance was very courteous, but none of their contracted tow trucks could get to me in less than 3 hours! The gave me the option of calling an independent and getting reimbursed (which is what I did). An hour and a half later, I was on a flat-bed at my local dealership (Ford of Bellevue) which was only 7 miles away. Their GT tech won't be in until Monday to make the definitive diagnosis.

By the way, the owner's manual recommendation for using 2x4's to decrease the ramp angle on the tow truck is no joke. The guy tried to do it without the boards first and there was no way it was going to clear. He put down one set of 2x4's (under the edge of the lift gate) and it just barely cleared in front by about 1/4 of and inch. Ford's recommendation of 2 boards stacked is probably better.

I'll keep you guys posted on the repair.

JAM

 

[Shadowman]

Thank you for sharing your less than pleasant experience.

Sadly with the weather becoming driver friendly I suspect that this cycle will be seen more and more.

Takes care

Shadowman

 

[nota4re]

JAM-GT,

Sorry to hear about your misfortune. Ford had better get their act together quick. In one of their rare comments on th situation, they explicitly claimed that the failure could only occur at very slow speeds. Well, err, I guess 70 mph is slow in a GT? Seriously, having a half-shaft loose and flopping around at 70mph is very dangerous! Make sure you carefully inspect for any collateral damage and get all of it covered under warranty.

Too strange that you posted this. Last night I just finished up a preventative upgrade on a customer's car using Accufab's kit. This car was a 2005 Serial number 14XX. (I don't remember the last two digits.)

The bolts were tight on both sides but the car had the silver, first generation, washers. I attached some pics. Kudos to Accufab - their kit is absolutely beautiful and takes maximum advantage of the limited space available.

The Accufab washer is much thicker and with a larger diameter as well.

Here are a couple of pics of the warped washer - which I'm convinced warps on assembly.

 

[analogdesigner]

Useful washer images!

JAM-GT,

Sorry to hear about your misfortune. Ford had better get their act together quick. In one of their rare comments on th situation, they explicitly claimed that the failure could only occur at very slow speeds. Well, err, I guess 70 mph is slow in a GT? Seriously, having a half-shaft loose and flopping around at 70mph is very dangerous! Make sure you carefully inspect for any collateral damage and get all of it covered under warranty.

Too strange that you posted this. Last night I just finished up a preventative upgrade on a customer's car using Accufab's kit. This car was a 2005 Serial number 14XX. (I don't remember the last two digits.)

The bolts were tight on both sides but the car had the silver, first generation, washers. I attached some pics. Kudos to Accufab - their kit is absolutely beautiful and takes maximum advantage of the limited space available.

The Accufab washer is much thicker and with a larger diameter as well.

Here are a couple of pics of the warped washer - which I'm convinced warps on assembly.

Kendall,

Thanks for the great images! I was waiting for something like this.

JAM-GT,

You should use an Accufab kit, however, the Ford dealer will probably be reluctant to install it for you, even if you were to pay for it yourself! Good luck, Jay

 

[Gimbal]

Damn JAM-GT glad to hear you are ok. Metal can always be fixed.
I never believed the problem could only happen at slow speeds. Could you please post any collatoral damage and anything else you might notice. Try and get the old bolts and parts, don't let them throw those away or keep them. It's good to know your rear wheel did not lock up at 70mph by having the shaft wedge against something.

Kendall, it looks like the Accufab and the Ford replacement washers are the same thickness, the original silver washers are thinner.

My GT had Ford replacement washers originally, I replaced anyway with the Ford kit. I have just received the Accufab kit and plan on installing that. My intention is to replace with Accufab bolts every 1000 miles or so until Ford or someone else comes up with a real fix.

 

[analogdesigner]

spare fasteners

My GT had Ford replacement washers originally, I replaced anyway with the Ford kit. I have just received the Accufab kit and plan on installing that. My intention is to replace with Accufab bolts every 1000 miles or so until Ford or someone else comes up with a real fix.

Gimbal,

Congrats on selling your company! :cheers

I like your idea of replacing the Accufab fasteners on a routine basis. A person would be wise to carry some spare fasteners if going on a trip, since an average mechanic could replace them for you in an emergency.

Jay

 

[Gimbal]

Hi Jay, Thanks a lot, selling my company was a good thing, getting thru the process was no fun though.

I'll keep some spare bolts, flashlight and wrench with me at all times. I should be able to get rolling faster than waiting for the right tow truck! One side I could do in 30 minutes.
But this is only possible if I am not involved in an accident or not collatoral damage.
I want the real fix though, hope it happens soon.

Gimbal

 

[Neilda]

What does the Accufab half shaft kit cost? I can't see any mention of it on their site.... Thanks. N