So I am starting my Turbo build and first step was putting in a stage 4 clutch. Started taking things apart and was loosing the subframe bolt and discovered the front 19mm bolts on both sides moved about a eighth of a inch then stop moving and free spinning but not coming out. I then loosened the other 2 bolts and once some pressure was on front bolt it started to come out but was very tight like it was crossed threaded, this happened on both sides. I was able to get them down about 2 inches so enough to get subframe down enough to do the clutch job. Now Im putting it back together and those dam front bolts will go in about a inch or so then just free spin. So I have the front bolts hanging down about a half a inch to 3 quarters of a inch and wont tighten up. Anyone else have this issue and if so what did you do? thanks in advance for any help. I searched and didnt see a post on this so started my own post.

 

Do a search. Its happened before. There are some tricks, but if all else fails, you have to cut the unibody frame to reach the nuts. Then weld in new ones, then weld where you cut. Not fun, but doable.

 

You have just encountered what is pretty much the biggest PITA a S2000 can present you (speaking from experience unfortunately). Like said above, you will have to cut holes in your car so you can reach the captive nut and replace it. I would recommend cutting the bolts and removing the engine and subframe first so you have space to work.

 

Probably doesn’t help you now, but when removing sunframe:

loosen all bolts 1/2”

Subframe will lower 1/2”, exposing the threads of the bolts above the subframe

Spray the threads with penetrating oil, then run them back in. This lubricates the captive nut threads

Then remove bolts

 

You can try new bolts and see if they will work. In my case they didn't work.

For a less invasive fix, instead of cutting open the body of the car to replace the welded in nuts, you can drill out the threads slightly, tap new threads, and use different bolts. I had to do this the last time I pulled my engine/trans and took a bunch of pics of the process. I ended up figuring out what the next larger diameter standard thread bolt was in order to only drill out the minimum amount of damaged threads needed to cut new threads. This process wasn't fun either but was way easier than having to cut holes in the car, weld back together, and repaint.

 

It may also be possible to drill out and retap to a larger size, but using the size that is correct for a helicoil of the factory bolt threads.

Then you can use new factory bolts.

Get helicoil kit that match the factory bolt threads. Kit will include drill bit and tap. This drill and tap are larger than the factory bolts.

Screw the helicoil in place. Replace subframe and install new factory bolts.

 

Dam first time I've read about subframe bolt issues.
Good to know - sounds scary

 

Hmm just ran into a similar issue myself.

The foward-most 19mm bolts on both sides came out about 1/2" with no issue, but then just get tight.

I tried to soak the exposed threads with Liquid Wrench and ran the bolts back up and it didn't seem to help too much in removal.

They went back in easily and I was still able to torque them back down to spec. Any other advice? I was thinking of taking a big m18 Milwaukee impact to it, but don't want to risk destroying the threads on the chassis.

 

Not the place for brute force. Time for patience.

Keep repeating the loosen, lube, tighten routine, trying to loosen a little farther each time. Go slow. Don't cause heat between nut and bolt. Use hand tools only, no power tools, no impact.

If you can get a really long brush, like an artist paint brush, try a craft store, you may be able to get some antiseize on those exposed threads.

Keep working it, slowly, little more each time, and it should come out. The time invested here will be well spent if it prevents the time it'll take to remove and fix it if captive nut becomes free.

 

I encounter this nearly every week. A powerful impact gun is key here. Impact breaks corrosion.

Impact them out to start. They will always go at least a half inch.

Lower subframe 1/2”. Spray penetrating oil UPWARDS into the threads. Retighten.

Impact again, when bolt starts to slow, respray, and tighten.

Repeat until the bolt comes out. The most it will take is around 4-5 cycles. I have not lost a battle with a single bolt (meaning they always come out)