Differential bolts broke again

[robmustang201528]

I did notice this tho. See underneath the bolt. It looks worn out

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[shogun32]

hopefully not too off base... So it appears there is some kind of threaded insert inside the Diff's front mount frame member (the black steel part in left picture of post #8 or 1st pic in #6). Does the insert float (molded into bushing) or mounted rigidly to the steel frame member? Does anyone have pics of the bushing recess with the bushings removed?

 

[Bharmsen]

Broke diff bolts doing a 60 roll. 3rd to 4th gear. No wheel hop. Shifted to 4th and it broke. Bk051 with the upgraded hardware bolt kit and it still broke smdh. Spoke to BMR and the recommended the BK054 with the upgraded hardware bolt kit. Has this happened to anyone else with the upgraded bolt kit. What kind of diff bolts are your guys running? Thanks





ATTACH=full]393904[/ATTACH] View attachment 393904 View attachment 393905 View attachment 393906

Mine broke while having the poly bushings with the lethal upgrade bolt kit so we ended up drilling through and used a solid bolt and nut on both sides and it's been good since!

 

[robmustang201528]

Mine broke while having the poly bushings with the lethal upgrade bolt kit so we ended up drilling through and used a solid bolt and nut on both sides and it's been good since!

Solid bolt and nut? BMR or steeda? Hows the NVH?

 

[shogun32]

the NVH of either is supposed to be little/negligible primarily because neither system is actually isolating the original rubber bushing. All the 'faceplates' are doing is helping to reduce the freedom of movement (pivot) which in the case of the rear bushing is a must-do as it's the primary source of the failure.

I don't understand Steeda's pricing. $110 vs $30 for BMR's kit. Sure the Steeda has 2 sets of plates but that shouldn't be more than a $30 upcharge.

The 10.9 bolt has a sheer limit of under 12,000lbs. But if the fastener's threaded section is taking the load that drops to about 7000 which is the equivalent of a grade 5 bolt. Or if you prefer, the sheer of an 8mm bolt instead of the original 10mm. That's ignoring the stress risers inherent in a thread form. Upping to 12.9 gets you approx 14% improvement.

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