so i went to see my car at the shop the other day and i noticed while it was on the lift that one of the bolts on my diff brace (driver side) was a tad loose, so i was twisting it with my hands and it just kept spinning, and wont tighten, what do you do about an issue like this?

 

Yea I had that same issue. It seems that the nut that the bolt screws into has broken its spot weld with the frame, so it just spins with the bolt. The really bad thing is that the nut is on the inner part of the frame and cannot be acessed even from inside the vehicle.

 

Drill it out and time sert it.

 

I drilled mine out and installed a bigger size nut and bolts

 

Thats exacly what it feels like,

 

Do this, they're also called "Nutserts".

 

Anyone have a picture of this?

 

You can Google "nutserts", they're a fairly common automotive repair.

 

At work right now, will search after thanks guys

 

so i wanted to see how this is used.. and saw this video... would this nutsert stay after tighting it to spec? vibration of the car or anything cause it to pop out?

 

They love to spin when tightened with any real amount of torque, the best way to keep it from happening is to tack weld them to whatever they're inserted into. The better option is just tapping out the holes though and re-threading them.

 

You can get ribbed ones that don't spin so easy as they bite into the steel when tightened.

 

Can't re-thread the hole.... What happens is the nut that Mazda tack welds on the inside of the frame breaks off. When this happens, the only metal left is the thin metal of the undercarraige. Hope that makes sense ..

 

This. Truth.

 

I was thinking of that, since it is a thinish metal, wouldnt just rethreading it and then tighting a bolt pretty much pull the metal/ thread, and then just have another issue?

So if nutserts wont work, what are other options?

 

Tac weld the nutsert to the body.

 

Lacking a welder, here's how I fixed that problem: https://www.rx7club.com/3rd-generati...2/#post9889675