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3.31 Limited Slip Axle X3L Separation/Sheared Studs

3K views 14 replies 7 participants last post by  ranxerox 
#1 ·
Yesterday My 2019 Ford Transit T250 had the entire right rear axle depart from the vehicle while driving. All studs obviously sheared off. I found the recall online (21S21) But searching the VIN online showed no recalls available. :'( Hoping the dealer can resolve this. 3.31 Limited Slip Axle X3L 3.5 EcoBoost Aluminum Wheels. Guess the recall so far was for the 410L Axle only.

Anyone else run into a situation like this?
 
#3 ·
Poorly done brake jobs will do it too when people reuse the same bolts instead of buying new ones.
See comment #1

 
#6 ·
If it was a Dealer they would know better? Look at your invoice, If they replaced the Rotors there should be 5 bolts per side, both Rotors would be 10 bolts replaced plus the 4 bolts for the Brake Caliper Anchor Plates.

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#8 ·
If you buy Ford OEM parts you have to specify each part, no package deal. Seem like a lot of people think a bolt is a bolt and replacing a seemingly perfectly Good bolt is silly and unnecessary also you have to get them from the Dealership, and they are a couple of dollars each , to much hassle just use the old ones. WRONG!
 
#13 ·
I had the same thing happen to my E-350 HD back in 1982. Looked in my mirror and saw the wheel sticking out about 3 feet and immediately applied brakes and the pedal went to the floor as the brake line was pulled off when the wheel detached. I managed to get it slowed down before the wheel came completely out and got off the road.

Some things never change, it appears.

It was a fleet maintained vehicle; I was told the axle was held on with a circlip that failed.
 
#14 ·
Elastic vs. Plastic Deformation
Speaking of strength, it’s important here to mention that when you tighten or “torque” a fastener in place, what you are doing is tensioning the shaft of the fastener as a very stiff spring. The tiny degree of elastic stretch you apply to a fastener by tightening it produces the powerful clamping force that holds the parts you are bolting together. When you elastically deform metal, the change of length or shape is not permanent. You are stressing the metal within its elastic range. When you apply even more force, and some of the deformation becomes permanent, the process becomes plastic deformation. Normally, threaded fasteners are used within their elastic range, which brings us to…


The Torque Wrench
Because it’s easy for an inexperienced person to over- or under-tighten critical fasteners, service manuals usually specify some way to directly measure installation torque. This generally means using a torque wrench. We don’t want head gaskets to leak or connecting-rod cap bolts to loosen, and we certainly don’t want the Mad Torquer breaking parts with the usual excuse, “Well, I didn’t want ‘er to come loose, did I?” More is not better. Correct torque is better.

But there are other tightening schemes which also allow us to achieve accurate fastener tension. One, practical only when both ends of the fastener are accessible, is to use a micrometer to directly measure how much tightening has stretched the fastener. This gives highly accurate results. Another is to spin in the fastener until firm initial contact is made, then turn the head through a specified angle. The idea here is that, say, a quarter turn on a 1.0mm pitch fastener will stretch it by 1/4 of a millimeter, which is 0.25 x 0.039 inch = 0.00975 inch.

Yet another method, more accurate still because it is based not on friction but on the properties of the material itself, is torque-to-yield. In this system, typically applied to critical fasteners such as head bolts, a torque-sensing wrench is used to tighten the fastener until it begins to yield (that is, the torque peaks and then begins to fall). Engineers know what force corresponds to the onset of yield for a particular fastener size, material, and heat-treat, so this method gives high accuracy, especially in automated assembly. Needless to say, fasteners tightened in this way cannot be reused.

Kevin Cameron
Cycle World

The rest of the article can be found here:

The Nuts and Bolts of Nuts and Bolts

 
#15 ·
Some bolts are not meant to be stretched, I once overtorqued sixteen 64mm bolts at work. Later they were inspected by a inspector and had to be replaced because they had been stretched, Try finding 64mm bolts in the US! We air freighted them in from Italy two days later. This piece of Italian built industrial machinery cost my company about one million dollars while the machine was unusable. (3 days) What can I say, There was no English translation for the installation manual. That fact helped me, The best I was able to tell I did not lose any money from my year end bonus.
 
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