Front clip replacement on 1973 mustang fastback

[Dakota]

Has anyone ever replaced both left and right complete front frames , torque boxes , and upper and lower cowls ? Looking for some good solid advice on how to under take this job. I have 25 yrs experience in sheet metal repair on commercial aircraft . I have a lot if sheet metal tools. I just want this to be a father son project. I did have it at a body shop , unfortunately it sat there for a year with nothing happening. So i brought it back to my garage / shop .

 

[rio1856]

Reach out and check with staff member "Mister 4X4" he did all that and much more on his sled.

 

[piper62j]

It's a lot of work if you're willing to put the time and effort into it.. The torque boxes are thicker than most of the other sheetmetal components and there are additional spot welds behind them going into the floor and firewall. Most importantly is the measurements from the top of the cowl panel to each end of the radiator support. Lower rail height from a level floor is equally important for the front suspension to be symmetrical. All of these measurements can be obtained here on this site from the frame diagram. Insure there is no twist to the aprons as this would affect the alignment of the hood and fenders on final assembly.. You really don't want to do this job twice..

 

[Mister 4x4]

Thanks for the nod, Rio! Yes, I did swap the entire front clip on mine with lots of advice and cheerleading from the fine folks here. My firewall and floor pans (along with the cowl, as I later discovered) were bad as well. I think Dakota will have a better time of it with his sheet metal working experience, as I was kind of learning on the fly, fueled by sheer determination - I did have some skills, but not what would be considered optimal for taking on such a job and expecting it to all work out. But, one never knows until one tries, right?

First thing you'll need is this chassis drawing - it offers up the measurements you'll need to ensure it all gets lined up going back together.

Basically, I supported the car on its frame on a drive-on lift (made life a LOT easier), and removed all of the non-structural items (suspension, steering, etc.). Then, I used a Sawzall to remove everything just short of the welded junctions and torque boxes, to make it easier to drill out spot welds against the firewall. The 'new' front clip I harvested from a '72 was missing a frame rail extension, so I repaired it, cleaned up the entire 'new' clip and coated with Rust Bullet Black Shell epoxy primer. After removing the last bit of 'flashing' (leftovers of the aprons on the firewall and various places) and separating the torque boxes from the rockers, I treated what was left of the firewall to some Rust Bullet, and got the whole thing ready to go back together. Lined it all up according to the chassis drawing, and welded everything back together. Once that was done, I turned my attention to replacing the floor pans, then came back to the cowl awhile later (after getting the engine put back together.

Here's a link to my Facebook album - shouldn't need to log in to view: https://www.facebook.com/media/set/?set=a.722153737795547&type=3

If that doesn't work, I started a blog to capture the same pics in chronological order, but only got up to the point of replacing the trunk floor and tail light panel - still got a ways to go on finishing up the blog: http://mister4x4.net/mister4x4/category/mach1/

** UPDATE ** I've been sick this past week with sinus issues (No COVID issues, fortunately), and after posting earlier, I decided it was time to catch the blog up (since I'm not doing anything else right now) - so, everything I've chronicled via my Facebook photo album is done now.

Hope this helps!