Another NA car breaks diff bolts...

ponie1992

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2016 Mustang PP GT with T56 Magnum XL swap. Installed a JPC line lock and ended up breaking the rear diff mounting bolts (BMR) on my fourth burnout attempt. I haven't looked at the front yet, but both rear bolts broke. The fronts may be damaged as well because the rear of the diff dropped down causing my DSS halfshafts to grind on the subframe. I didn't look for any further damage because I was completely disgusted by this happening. The halfshaft boots are destroyed and I only hope the halfshafts themselves are ok. Also praying my driveshaft is ok, which I believe contacted the fuel tank shield because lots of fibers were on the ground.
I'm gonna pull the entire cradle, assess and repair once I can prepare myself for more possible disappointment. I'm posting this for others who may have or will install a diff mount bushing kit. My advice is to upgrade to stronger bolts or the through bolt upgrade.
Enjoy a good laugh at my expense:

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xXoVrKiLLXx

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2016 Mustang PP GT with T56 Magnum XL swap. Installed a JPC line lock and ended up breaking the rear diff mounting bolts (BMR) on my fourth burnout attempt. I haven't looked at the front yet, but both rear bolts broke. The fronts may be damaged as well because the rear of the diff dropped down causing my DSS halfshafts to grind on the subframe. I didn't look for any further damage because I was completely disgusted by this happening. The halfshaft boots are destroyed and I only hope the halfshafts themselves are ok. Also praying my driveshaft is ok, which I believe contacted the fuel tank shield because lots of fibers were on the ground.
I'm gonna pull the entire cradle, assess and repair once I can prepare myself for more possible disappointment. I'm posting this for others who may have or will install a diff mount bushing kit. My advice is to upgrade to stronger bolts or the through bolt upgrade.
Enjoy a good laugh at my expense:
That sucks; so sorry dude. It will wash out though and be right when you are done. Subbed to the channel!
 
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ponie1992

ponie1992

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That sucks; so sorry dude. It will wash out though and be right when you are done. Subbed to the channel!
Thank you, man! I'll get er fixed, just had to walk away for a bit. Very much appreciate you subbing! Maybe one day I'll be able to make some cash from youtube and be able to afford these kinds of issues lol.
 

Martin5.0sc

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That dam red company strikes again smh, thanks for sharing man and sorry for your troubles I’ll be swapping mine out ASAP
 
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ponie1992

ponie1992

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That dam red company strikes again smh, thanks for sharing man and sorry for your troubles I’ll be swapping mine out ASAP
Yeah man, wish I was better informed before installing these. I had seen a little about it, but thought I should be good since I'm still NA. Oh well, live and learn. Just hope my axles and driveshaft aren't damaged. But, hopefully this will save some people from going through this.
 

moffetts

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Is this the hardware that comes with the BK051 kit? I’m really not sure why the hardware upgrade kit (rh017) isn’t included with the bushing/insert upgrades.
 
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ponie1992

ponie1992

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Is this the hardware that comes with the BK051 kit? I’m really not sure why the hardware upgrade kit (rh017) isn’t included with the bushing/insert upgrades.
Yep, that's the kit. I wondered myself why they don't include upgraded hardware.
 
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ponie1992

ponie1992

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So, I finally gathered the courage to crawl under the car and see what's damaged. As long as my axles are not hurt, they should only need boots. Gonna have the driveshaft balance checked, but it should be good. The driveshaft came in contact with the parking brake cable and has a small width scrape all the way around. The rear u joint end tore up the silver heat shielding that's stuck to the fuel tank cover. Here's a few pics.
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TeeLew

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All in all, I think you pretty much got away with this one. If I were you, I'd drop the driveshaft and have a shop (unless you have a big lathe) polish that witness mark off.

I have that same kit and you can bet I'll put some better hardware than it came with back in. Thanks for the heads up.
 
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ponie1992

ponie1992

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All in all, I think you pretty much got away with this one. If I were you, I'd drop the driveshaft and have a shop (unless you have a big lathe) polish that witness mark off.

I'm have that same kit and you can bet I'll put some better hardware than it came with back in. Thanks for the heads up.
Yeah man, my plan is to take the axles and driveshaft to DSS and have them give everything the once over. Once they're good to go, I plan to make the cradle bullet proof before it goes back in. Well, as bullet proof as I can get it anyway. I'm glad I can pass this on so others can avoid this altogether.
 

StangTime

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Subscribed to your channel. Sweet car you have there. Sucks that you broke it. Hopefully doesn't cost you too much to repair. Are those regular grade 2 bolts that come with the BMR bushing kit? What are the markings on the bolt heads? They don't say on the website. I would be putting in at least a grade 5 or grade 8 bolts so they can handle the repeated stress.
 
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ponie1992

ponie1992

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Subscribed to your channel. Sweet car you have there. Sucks that you broke it. Hopefully doesn't cost you too much to repair. Are those regular grade 2 bolts that come with the BMR bushing kit? What are the markings on the bolt heads? They don't say on the website. I would be putting in at least a grade 5 or grade 8 bolts so they can handle the repeated stress.
Thank you for subscribing! This is the standard kit, which I believe has 10.9 grade bolts. The upgrade bolt kit is 12.9. I'll be going back with a through bolt setup, which I think most people use grade 8 9/16 bolt and nuts.
 

StangTime

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Thank you for subscribing! This is the standard kit, which I believe has 10.9 grade bolts. The upgrade bolt kit is 12.9. I'll be going back with a through bolt setup, which I think most people use grade 8 9/16 bolt and nuts.
I would check the markings on the heads to be sure they didn't send the wrong bolts. Hard to believe you broke a 10.9 !
Rebuild it to run longer and stronger.
 

Martin5.0sc

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Threw bolt design is very involved if your not pulling diff already, you need room to drill out the threads in the front bushing mounts for threw bolts, I think I’ll just up grade to the 12.9 hardware kit from BMR, Steeda if they have it.... this is bullshit BMR wouldn’t use the 12.9 hardware anyway with their bushing inserts, they’ve known about this problem for a long time now
 

K4fxd

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I wonder if the factory setup would have broke. I'm thinking the inserts caused the added shear stresses on the bolts.
 
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