Differential bolts broke again

[robmustang201528]

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





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[BlackandBlue]

Have you pulled the bolts yet?

What do the bolts look like?

 

[robmustang201528]

Not yet. The back of the bolt is still there 2nd picture

Have you pulled the bolts yet?

What do the bolts look like?

 

[TheHydro]

I never broke bolts but had problems with my diff moving with the lockout kit and regular bolt set up. I through bolted it using the kit from Lethal and haven’t had a problem since.

 

[Jeff's FRC]

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





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I'm not seeing your pics. You broke the RH017 12.9 grade bolt kit?

I never broke bolts but had problems with my diff moving with the lockout kit and regular bolt set up. I through bolted it using the kit from Lethal and haven’t had a problem since.

How do you know the diff was moving?

 

[robmustang201528]

I'm not seeing your pics. You broke the RH017 12.9 grade bolt kit?

How do you know the diff was moving?

 

[TheHydro]

I'm not seeing your pics. You broke the RH017 12.9 grade bolt kit?

How do you know the diff was moving?

I could tell it was moving because the small teeth on the diff ears were sticking out. When I would loosen the bolts the diff would drop back down to where it was suppose to be. There is a good video BMR did about the kit lethal sells.

 

[robmustang201528]

Yeah. I broke the RH017 12.9 grade bolt kit.

 

[robmustang201528]

I could tell it was moving because the small teeth on the diff ears were sticking out. When I would loosen the bolts the diff would drop back down to where it was suppose to be. There is a good video BMR did about the kit lethal sells.

This has happened to me before. Why does this keep happening? Is the diff flexing during hard shifts? Breaking the bolts during shifts? How do I keep the diff from moving? I'm thinking the shop didn't torque it down to spec? Is that a possibility?

 

[shogun32]

use the correct shank bolts. Or shim to correct size. You *never* rely on fastener torque to limit movement in an oversized hole.

 

[robmustang201528]

I'm not seeing your pics. You broke the RH017 12.9 grade bolt kit?

How do you know the diff was moving?

I think the diff was moving under hard shift. How do I prevent it from hard shifts? I'm really not looking forward to the

use the correct shank bolts. Or shim to correct size. You *never* rely on fastener torque to limit movement in an oversized hole.

use the correct shank bolts. Or shim to correct size. You *never* rely on fastener torque to limit movement in an oversized hole.

I'm using the correct bolts..it fills up the hole.

 

[shogun32]

I'm using the correct bolts..it fills up the hole.

every hole? Or just the diff bushing? I might be mis-remembering but I swear I saw some pics where the holes in the casting were oversized.

 

[Dominant1]

Are you still using the stock rubber bushings? If so thats the reason why you keep breaking bolts. You need a stiffer bushing to share the torque load...

 

[shogun32]

I was referring to this: https://www.mustang6g.com/forums/th...extreme-differential-bolt-upgrade-kit.122228/

Now maybe both of these inexcusable engineering F-up is no longer the case with 18+ cars...

 

[robmustang201528]

Are you still using the stock rubber bushings? If so thats the reason why you keep breaking bolts. You need a stiffer bushing to share the torque load...

I'm using the BK051 bushings from BMR and the bigger diff bolts from BMR. I also have the BMR vertical links and cradle lockout

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