Broken Motor Mount/Subframe connector

[SloCal]

So when i went to install my Mountune RMM last week I didn't realize I had a broken torque wrench. As such it never clicked and i overtightened it. Now the threads inside the nut on the subframe connecting point are stripped and the motor mount won't torque to proper spec. Before I go to Mountune and pay 100+ an hour to attempt to remedy this I was really looking for any ideas or experience in f****ing up this bad. My only idea was to get a long bolt and put a nut on the end but it won't tighten through the existing one and i don't know if that's safe or if it will work.

So basically I'm trying to fix this before i have to drive to work on Monday

 

[frankiefiesta]

Possible to retap the threads?

 

[CanadianGuy]

Ya retap or helicoil. In a pinch you could use thread lock to keep the low torque much stronger but that would be to get to a store to get the part you need to fix it kind of fix.

 

[Joe Schmoe]

I did this once on another car, so I ran a tap though the mount and the chassis.......then I sheared the tap in the hole with nowhere near enough to get ahold of. Needless to say the tap remained right where it was, holding that part of the mount in place until that car was traded in. I'd send this one to the pros.

 

[SloCal]

So my solution is going to be to run a thinner bolt through the area with a lock nut on the outside of the original welded nut. But i'm not sure if i'm being an idiot or not but what bolt size do i buy?
According to ford service parts stores online, the bolt is an M10 x 80 so i was going to go with M8 x 90 or 100. However we use a 13mm wrench on the bolt so isn't it an M8 bolt.
You would use a 13mm wrench on an m8 bolt and a 15 on an M10 so am i being inept or is the parts store wrong and the original bolt is an M8 in which case i would go with an m7 or m6?

Thanks

 

[grnmachine02]

I would just get a harbor freight tap kit, or some helicoils. This is a repair you only want to do once, so do it right.