Rear shock mount broken.
Fleet Mechanic
Joined: Apr 2015
Posts: 1,641
Likes: 507
From: Phelan CA
I don't think it was whoever put the hitch on.
Rather, it was whoever put the aftermarket shock on.
The B&W hitch was in the way of the OEM shock removal.
Clearly the shock bolt was cut off with a reciprocating saw AFTER the B&W hitch was already installed, because we see the witness marks of the cutting action on the B&W cross rail (creating a stress riser / weak point on that cross rail that supports the hitch).
The shock mount is not in the way of the B&W hitch installation. Instead, the B&W hitch installation is in the way of the removal and replacement of that rear shock. The shock shown by the OP is an aftermarket shock, which suggests that the shock mount stud was cut to remove the OEM shock, as the B&W hitch interfered with pulling the OEM shock off of the stud.
I have read, but have not confirmed, that B&W has since changed the design of their cross rails for this application, to avoid this all too commonly reported problem.
Rather, it was whoever put the aftermarket shock on.
The B&W hitch was in the way of the OEM shock removal.
Clearly the shock bolt was cut off with a reciprocating saw AFTER the B&W hitch was already installed, because we see the witness marks of the cutting action on the B&W cross rail (creating a stress riser / weak point on that cross rail that supports the hitch).
The shock mount is not in the way of the B&W hitch installation. Instead, the B&W hitch installation is in the way of the removal and replacement of that rear shock. The shock shown by the OP is an aftermarket shock, which suggests that the shock mount stud was cut to remove the OEM shock, as the B&W hitch interfered with pulling the OEM shock off of the stud.
I have read, but have not confirmed, that B&W has since changed the design of their cross rails for this application, to avoid this all too commonly reported problem.
Fleet Mechanic
Joined: Feb 2021
Posts: 1,405
Likes: 1,171
From: East TN
Single shear is not nearly as stupid as the person who cut that bolt to install an aftermarket shock. How many MILLIONS of single shear point applications are out there, just waiting to fail suddenly, causing untold trillions of dollars of damage to occur? I shudder to think about it... 
The shear strength of a fastener is approximately 60% of its rated tensile strength. A Grade 8 or 10.9 fastener has a tensile strength of 150,000 PSI. 60% of that would be 90,000 PSI of shear strength. Obviously that is more than adequate for supporting that shock in a truck or car - which is exactly why the manufacturers use them like that.
The shear strength of a fastener is approximately 60% of its rated tensile strength. A Grade 8 or 10.9 fastener has a tensile strength of 150,000 PSI. 60% of that would be 90,000 PSI of shear strength. Obviously that is more than adequate for supporting that shock in a truck or car - which is exactly why the manufacturers use them like that.
Tuned
Joined: Apr 2021
Posts: 396
Likes: 187
From: Montana
Single shear is not nearly as stupid as the person who cut that bolt to install an aftermarket shock. How many MILLIONS of single shear point applications are out there, just waiting to fail suddenly, causing untold trillions of dollars of damage to occur? I shudder to think about it...
The shear strength of a fastener is approximately 60% of its rated tensile strength. A Grade 8 or 10.9 fastener has a tensile strength of 150,000 PSI. 60% of that would be 90,000 PSI of shear strength. Obviously that is more than adequate for supporting that shock in a truck or car - which is exactly why the manufacturers use them like that.
The shear strength of a fastener is approximately 60% of its rated tensile strength. A Grade 8 or 10.9 fastener has a tensile strength of 150,000 PSI. 60% of that would be 90,000 PSI of shear strength. Obviously that is more than adequate for supporting that shock in a truck or car - which is exactly why the manufacturers use them like that.
Cargo Master
Joined: Jul 2017
Posts: 2,300
Likes: 554
yea some of you guys are taking my comment way too seriously. generally, sure they are fine. but for some applications, its just pure laziness. Single shear steering tabs, single shear shock mounts, single shear upper control arm mounts etc etc.
Cargo Master
Joined: Nov 2007
Posts: 2,238
Likes: 475
Single shear only has one failure point, which is the biggest reason it shouldn't be used in critical areas like steering and suspension mounting, even if it is over-engineered. A shock really isn't critical, so it's arguable, but it wouldn't have been anymore difficult, or probably expensive, for Ford to have designed a simple stamped double shear bracket like I've seen on numerous other vehicles. I've always wondered why they did it up front but not out back when they changed from stud mounts to eyelets up top back in the 80's.
Fleet Mechanic
Joined: Apr 2015
Posts: 1,641
Likes: 507
From: Phelan CA
Single shear only has one failure point, which is the biggest reason it shouldn't be used in critical areas like steering and suspension mounting, even if it is over-engineered. A shock really isn't critical, so it's arguable, but it wouldn't have been anymore difficult, or probably expensive, for Ford to have designed a simple stamped double shear bracket like I've seen on numerous other vehicles. I've always wondered why they did it up front but not out back when they changed from stud mounts to eyelets up top back in the 80's.
Surely an alloy steel stud through welded into plate can handle measley loads acted upon it by a shock
Now if you clarify that a bolted connection is best in double shear, I agree 💯.
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