Pre-clutch tube repair questions, Need some advice from welders Options

[ThinAir]

I'm getting ready to fix the clutch tube on my '73. It's not just loose like your typical clutch tube repair. In my case the firewall is broken away in about a 2x3" rectangle and I can see that the rear 3-4" of tube are gone along with the firewall section.

I've got a parts car that I need to start cutting up. My plan is to cut the center tunnel along each side where it meets the floor panels so that I can remove the whole tunnel. Once I get it out I'll drill out the spot welds so that I can get to the tube from the open bottom. Once I get that far I should be able to separate the tube from the side of the tunnel so that I can move it to the '73.

So I've got 2 questions:
1) Is this a good plan?
1a) Is there a source for a "new" clutch tube that I should use instead of trying to get this one out of the parts car?

2) What kind of spot weld drill works best? Here's one type that I've seen:

[ThinAir]

Here's the other type that I've seen. Any recommendations:

[McMark]

Re: Clutch Tube Repair: If the tube itself is still in good condition you can just patch/weld it back into place. you don't need to replace the whole center tunnel. Pics?

Re: Spot Weld Drill Bits: I just use a standard 5/16 drill bit, but it takes a little more practice to perfect. I've got thousands of spot welds under my belt. The one in your first post is a little easier to use from what I've heard. Both work pretty well.

[Mike9142.0]

Mark
The clutch tube is missing the rear most 3 to 4" and 2x3" peace of the fire wall around where the tube comes out.

[ThinAir]

Here's a shot of the firewall showing the missing piece. I don't have a picture of the tube itself, but it's missing for the rear 3 or 4" so it's not your usual clutch tube repair. The front of the tube actually seems to be quite well attached!

[McMark]

I still wouldn't replace the whole center tunnel. You could cut out the clutch tube and a section of firewall. The clutch tube is held in at three points. The firewall is one point, here is point two:

[McMark]

Here is point three:

[ThinAir]

I still wouldn't replace the whole center tunnel.

Sorry if I gave the wrong impression. I'm not planning on replacing the entire center tunnel.

I was asking about whether there was a way to replace the clutch tube with a "new" clutch tube since I'm missing such a big piece of the existing tube.

If not, then I was asking about my idea for cutting the center tunnel out of the parts car so that I could easily get into it and remove the clutch tube for reuse in the 73 that has the tube problem.

[McMark]

Ahh. (IMG:style_emoticons/default/biggrin.gif) Yeah, you can get them out. The hardest connection to break would be the one in the middle. The one near the front of the car is spot welded on the drivers side vertical of the tunnel. You can find that spot weld and drill through it to free the front. The rear will obviously come out with a section of firewall. The bracket that the center is braized to has other tubes on it as well and is spot welded to the top of the tunnel. You can cut open the tunnel in that area and chop off the bracket as necessary.