Working on installing the Z1 subframe collars and I got everything out except for this one bolt that just keeps spinning. I broke it loose and it started going and then it just started spinning. Can’t tighten or loosen it. This is the front side of the rear subframe on the driver side. 2005 g35 coupe 6MT

 

What year is your G? I don't even recognize that subframe, I thought they were all aluminum?

 

2005. This is just a bracket that secures the subframe to the chassis.

 

Ok so that's the bolt that was next to the "W" brace right? That's the one that goes up into the chassis and the other one next to it had a nut on a stud protruding from the chassis I think?

If that's the one I'm not really sure how the threads were retained into the chassis. I would try taking a prybar to put more pressure down on the fastener while you hit it with an impact wrench again but the captured nut or whatever it uses is probably spinning up in the chassis somewhere. Might have to get a little creative with a drill and make an "inspection window" to look up in the chassis to see what's going on.

 

Yep, precisely. I tried sticking even a small flat head screwdriver behind the head of the bolt but there is no room whatsoever to pry with anything. That was my next guess; grinding the bolt head off and dropping that bracket out of the way to see if there’s a nut I can access on the other side or if I’ll have to grind out a window to gain access to the nut, then I guess just try and clean it up and weld a new nut on or something.. just hoping the bolt isn’t threaded directly into the chassis.

 

If it is directly to the chassis you can oftentimes just keep drilling up through the sheet metal until you hit a spot where you can put a nut in then use some 1/2" allthread and make a new bolt. I'm showing that one needs to be torqued to 33 ft/lbs so a piece of grade 5 1/2" allthread would be plenty stout.

You might also be able to nutsert into the sheet metal if you have a nutsert crimp. It wouldn't shock me if the factory used nutserts for lighter stuff like that. Normally you only start getting captured nuts for bigger bolts.

If you don't have a nutsert crimp check this one out, it's got a VERY wide range of sizes in both metric and SAE and comes with everything you need (except drill bits) to get going.

 

Hey did you ever find out a solution to this? I have the exact same issue except at the front of the w brace. I managed to get the bolt out but there are no more threads to mount up the last 14mm bolt..

 

tapped a square piece of steel, cut a slit in the frame large enough to slide it in, welded it in place, bolted brace down.

 

Nice I'll try this out the hole is bent don't know if that would effect it or not