1969 Mach1 Quarter Panel Repair

[NasaGT]

Hello all,

I've been busy lately repairing the driver's side quarter panel on my 1969 Mach1. I have found very little on 69-70 quarter repair in searches, so I thought I'd share my progress with anyone interested, but I'm really posting because I have a question I'm hoping some of the experienced body guys might answer.

So here's what I started with. This car was involved in an accident on the drivers side, and there was major damage on the front end, but also with damage at the door jamb along the quarter panel, and to the rear of the quarter panel near the taillight panel. Additionally the wheel arch was rusted and the lower rear of the quarter is almost completely gone from rust.

I decided to use a skin rather than the a full replacement panel for a couple of reasons. First skins are waaaaay cheaper. I'm not in a huge hurry to get this done, and I can't just throw money at the car. The engine is going to suck up enough money, the more I can save on the body the better. The second reason is that I'm a big believer in keeping as much original metal as possible. Finally if I went with a full quarter I would want the full panel leaded in, and I don't know how to do that yet. I think I'm going to try leading soon, but thats another story.

So I cut out the bad metal, straightened a few things, replaced the outer wheel house, and did lots of other little things that I won't bore you with. Then I laid the skin over the original quarter panel (after cutting the skin closer to size). I didn't want to cross any body lines, so my cut line was under the scoop, then over the wheel arch, and finally over the damaged metal on the rear of the quarter panel.

Not shown is the couple of hours spent getting the flange correct where the quarter skin meets the rocker panel. The skin has a very soft rounded bend there, it takes a good bit of hammer and dolly work to get the flange in the correct location, and then nice and crisp. Ask me how many time I thought I was done working that flange....

Then I cut both the skin and the original quarter panel at the same time with a cutoff wheel. Here you can see the panel held on with butt weld clamps

 

[NasaGT]

Quarter panel continued

So after a little hammer and dolly work here and there the panel was ready to weld

Spot welds were made at least 6 inches apart skipping around on the quarter panel. This pic shows several passes of spot welds and the butt weld clamps removed

The spot welds were ground down and then I used the hammer and dolly to tweak the quarter panel straight. It already had a few highs and lows, but nothing really bad at all. This just insured that the shape of the panel was still correct. After that I slowly started adding spot welds spaced pretty far apart, only doing maybe 8-10 at a time. After several more passes it looked like this

Then I ground those down and did some more hammer and dolly work.

Then back to well spaced spot welds. Finally all of the gaps were filled and ground down.

It turned out pretty well. I've got a little low spot right above the wheel arch that needs some work. Not sure how I'm going to work that yet since the wheel house interferes with 'normal' hammer and dolly work there (and is probably why its low there to begin with). All in all I'm very happy with it so far.

 

[NasaGT]

Finally the freakin' question

Now for my question. I wish I had realized this before I had so much welded together, but that just makes this a little harder to deal with eh?

Here's the bottom of the rear of the passenger quarter panel.

You can see that the bottom is recessed quite a bit and the quarter flange matches up with whats left of the trunk pan. Now for the drivers side with the skin:

The bottom of the skin is flat, and the flange that should mate up to the trunk pan dropoff is low. In fact the bottom edge of the trunk dropoff is even with the top part of the flange on the quarter.

So after all these pics and gibberish, we finally get to my question. Whats the best way to handle this? I see three ways to deal with this

1) cut and section the bottom of the quarter, bend to match up with the trunk pan, fill in a few gaps and be done
2) buy 65-68 trunk pans which are 1" longer than the 69-70 trunk pans and move on
3) extend the 69-70 trunk pans

I already have 69-70 trunk pans (they came with the car). But they're older repros and the trunk dropoff is 1/2" to 3/4" shorter than the original. So if I used these I already to work these a bit, or just buy new pans. They're only $30 each so not a huge cost associated with buying new ones.

Maybe there are other options. Any ideas?

 

[golf4283]

What's the strength of the quarter panel patch? I thought I read they were thinner metal and more susceptible to dents? I need to replace my passenger side quarter on my '66 and am debating between a full and a patch panel. I don't want to mess with the lead so if I go full I will cut it to avoid dealing with the lead work but I'm just curious as to the strength of the patch panel.

 

[NasaGT]

Its the same thickness as the original sheet metal. I checked them both prior to welding.

I had heard the same thing, I'm guessing that might have been true of early reproductions.

 

[NasaGT]

No one has done this before?

 

[BarnStang]

Nasa, nice work. I have not done a qtr that way but have considered it. I may try that when I get back to my 66. I have always used my air flanger on the upper part but welded the joint the same way.
On the bottom, have seen this a lot. Cut the corner and drift it up. You may also see a problem with the valance-its flat too where the other side is recessed. THis will cause a problem with the little bracket on the valance-it will not sit close enough to the body line. I normally cut the bracket off the valance, trim it and weld it back on so it does not stand-off from the valance so far, allowing you to pull it up tight to meet that body line better. I can't see exactly, but it looks like your qtr patch does not have the hole in it for the valance mounting either so you will have to locate that hole but you have lots to cover it up so not a big deal as long as you get close.
Lastly-DONT FORGET to check fit the valance side to side before you tac the other qtr. Make sure the bottom of the qtr is not sticking out too far or pulled in too far-ask me how I know...its' better to check this before either side is tac'ed so you aren't trying to get all the adjustment out of one side. You should have some flex and adjustment before you attach the qtr to the trunk drop.

 

[NasaGT]

On the bottom, have seen this a lot. Cut the corner and drift it up. You may also see a problem with the valance-its flat too where the other side is recessed. THis will cause a problem with the little bracket on the valance-it will not sit close enough to the body line. I normally cut the bracket off the valance, trim it and weld it back on so it does not stand-off from the valance so far, allowing you to pull it up tight to meet that body line better. I can't see exactly, but it looks like your qtr patch does not have the hole in it for the valance mounting either so you will have to locate that hole but you have lots to cover it up so not a big deal as long as you get close.
Lastly-DONT FORGET to check fit the valance side to side before you tac the other qtr. Make sure the bottom of the qtr is not sticking out too far or pulled in too far-ask me how I know...its' better to check this before either side is tac'ed so you aren't trying to get all the adjustment out of one side. You should have some flex and adjustment before you attach the qtr to the trunk drop.

Thanks Barnstang! Great comments, I was hoping someone who had wrestled with this would chime in. That helps greatly.

Yeah, I had checked the rear valence. I bought a new one from NPD, and it fits the passenger side perfectly. Looks like it will fit the drivers side correctly as well after a little work to the rear flange on the quarter just under the taillight panel. That flange is in the way right now. And like you said there's no hole for the valence in the quarter panel.

I'm in the middle of getting the trunk floor pan out of the drivers side, once I get that out I'll start cutting the bottom of the quarter panel. I'll post pics when I've got something to show, I'm mostly a weekend mechanic, not alot happens during the week usually so its slow going...