Another NA car breaks diff bolts...

aleccolin

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For a threaded connection, ideally you would want a counterbored hole in the ear which would allow the grip of the bolt to extend fully through the joint and into the ear before the threads engage. That would require some sort of custom shoulder bolt or a sleeve sized to the counterbore, which is what I mentioned earlier. Ultimately, it is easier to drill out the threads to 16mm nominal diameter and through-bolt with a 16mm bolt. You can go larger than that, if you want to also drill out the bushing.
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shogun32

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he only way I would clearance the ears on my diff. would be on a mill, not with a grinder or Dremel
naturally. But a standoff (5mm?) should also let the nut clear. Either way it's a piss-poor design and puts the sheer into the threaded portion of the fastener which is grade F engineering.
 

KellTrac

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If you are using the factory threads, you really have not made a true upgrade. No current offering that still retains the OE threads has been immune to failures, regardless of what marketing materials may claim.

The best way to avoid issues is to simply use larger diameter hardware.

I will also add, the Steeda diff bracing should help tremendously as well. It all depends on how you want to set it up.
 

NGOT8R

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If you are using the factory threads, you really have not made a true upgrade. No current offering that still retains the OE threads has been immune to failures, regardless of what marketing materials may claim.

The best way to avoid issues is to simply use larger diameter hardware.

I will also add, the Steeda diff bracing should help tremendously as well. It all depends on how you want to set it up.
I hear you KellTrac. I’ve heard of some auto guys breaking the ears tight off their diffs on hard lunches with sticky tires. Steeda and BMR, what say you on all of this?
 

KellTrac

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I was the first person to snap ears off the diff, actually. October 2015. I am well aware.

If NVH is not an issue, a solid Diff bushing is the best solution 100%, there is zero debate. It strengthens the entire system and I have never seen a single "failure" with them. I am not referring to inserts or lockouts, I am referring to solid aluminum full replacement.

Personally, I tell people to keep the bushings stock. Then if you tear a bushing, use a through bolt kit with a diff "lockout" or "insert" in poly material.

BG Break.jpg
 

shogun32

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I hear you KellTrac. I’ve heard of some auto guys breaking the ears tight off their diffs on hard lunches with sticky tires.
the point is to minimize freedom of movement. If it can't move, it can't break (within reason).
I used the WhiteLine total replacement system. Cheap and effective and very minor noise compared to the 'puck' solutions.
 

WD Pro

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just one example. There are at least 3 companies offering this. I'm talking about the top left/right item. It reduces the 16mm hole in the Ford bushing to 14mm to match the dia of the bolt. It's a mind-blowing catastrophic error by Ford engineering which apparently they can't be arsed to fix in 5 years. I wonder if the GT500 got a correctly designed part.

http://m.bmrsuspension.com/?page=products&productid=1764
That’s for the subframe, need the rear diff bolt bushings, 16mm OD, 14mm ID
smidge shy of 2"
Let hope you guys are right … :like:

1-DAB6-E5-F-A6-F5-4-BE9-B105-2-BA12-E7-EDB8-C.jpg


WD :like:
 

WD Pro

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Stainless :like: Ti is for my (push) bikes …

WD :like:
 

WD Pro

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Are you planning to counterbore the ears on the diff cover for these?
No, they just take up the sloppy fit of the M14 bolt in a 16mm clearance hole :

1625816502107.png


WD :like:
 

aleccolin

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What would be better, carbon fiber or titanium? I found 16mm OD x 1mm wall round tube in both, similar price. Probably too many variables to carbon fiber composite to know the exact compressive strength, but having trouble even finding a ballpark for comparison.

I also found copper for even less, but assumed it was too soft. However, maybe it would still work in this application?

Also I was thinking it would probably help to use some ARP lube on the threads and under the head of the bolt when torquing to be sure you get 100% of the bolt stretch to increase friction between the ear on the diff and the mounting bushing, making it less likely to slip under load. I need to look at how the grade of the bolt affects the required installation torque.
 
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shogun32

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you can probably use Delrin and suffice. the point is reducing freedom of movement. Do NOT lube the threads without reducing the torque value. A giant WAG is 30% reduction from dry. All of the female threads are in AL as I recall so ripping out the threads with a steel fastener is a distinct possibility. Save yourself the trouble and just drill the threads out and thru-bolt it. :)
 

GTP

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What would be better, carbon fiber or titanium? I found 16mm OD x 1mm wall round tube in both, similar price. Probably too many variables to carbon fiber composite to know the exact compressive strength, but having trouble even finding a ballpark for comparison.

I also found copper for even less, but assumed it was too soft.
...
Let us know when you find them in steel or stainless. I couldn't.
 
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