I thought I would post this up as this is a pretty common issue on our cars and this is a simple fix that doesn't require welding, or drilling holes though your floor from the inside. It uses knurled inserts sometimes known as nutserts.
I have used nuts welded to about a 10" pc of 3/16" rod for years..that was a major pain in the a$$ to install the cross member bolts with. I finally fixed the car for good using this solution!

Parts:
1. Spaenaur Knurled Threaded Insert #216-K15-1C (on box) or #216-049 (catalogue) (see pic)
2. Holding tool = Flat Bar, 1/8"thk x3/4"x10"long with a 7/16" hole in one end (see pic)
3. Cross member to frame bolt M10x1.5
4. 4 or 5 flat washers that fit on M10 bolt (see pic)
5. 13.5mm = 0.531" drill (I used 1/2" and file open the holes to suit)

Steps:
1. Remove cross member, drill out stripped threaded holes using 13.5mm drill or use 1/2" and open the holes to suit using a die grinder, just enough so you can pound in the insert. You want a tight fit, loose may not grip the insert well enough.
2. Thread a 10mm bolt into the insert and pound it into the drilled hole until flush with frame bottom (as far as it will reasonably go).
3. Remove the 10mm bolt from the insert and put 4 or 5 lubricated flat washers on it, then install into Holding Tool (see pic). Make sure the bolt is long enough to go completely through one of the inserts, ie all the insert threads are engaged.
4. Thread the bolt into the installed insert, hold the tool from rotating and tighten bolt, compressing the insert and locking it into place.
5. Do the rest of the stripped holes..you're done.

Pictures:













Here are some links to other repair threads for your reading pleasure:
https://www.thirdgen.org/forums/susp...bolt-hole.html

https://www.thirdgen.org/forums/fabr...rent-bolt.html

https://www.thirdgen.org/forums/tran...-stripped.html

 

This thread has some more feedback and discussion on the inserts!

https://www.thirdgen.org/forums/tran...-stripped.html

 

Thank you for posting this how to , I see the other ways are not as clean and I hate seeing hack jobs on our cars.

The "swampy" bypass to get to the fuel pump is another one that annoys me, on third gens it is easier and CLEANER to just take the tank out as the General intended.

I made a video following your instructions. Hopefully some of these folks will see it and follow suit. I almost drilled a hole between the two and welded a plate on the inside with nuts as described by a thirdgen member.

I decided to follow your guidelines and I am very pleased, I got the nutsert from a local dealer here, cost me a $1 each. Install took about an hour. It is such a better alternative to cutting the frame.

thank you for posting.

my video. an ODE to 6speedIROC

 

I just drilled and tapped what was there to a larger size. Worked great so far.

 

The better option is to drill the hole out to the next size and re-tap the hole. I'm not sure if the nut-sert will support the weight involved, not to mention what pita it will be when it starts to spin next time you try to take it apart. They are not very heavy duty.

If the factory threaded captured nuts are broken off and completely gone, a better bet would be to weld in a metal plate with nuts welded to it to replace everything.

 

Time-sert is probably the best idea. Not sure if 86 was referring to that, or, what he was trying to say.

 

I fixed my post, idk what happened there, lol.

 

my frame rail there,,,where the crossmember bolts to is cracked due to rust and shifting...can I fabricate a bolt on piece?