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69 vert underbody repair process

7K views 27 replies 8 participants last post by  truss 
#1 · (Edited)
Hey guys, All of my underbody floor parts arrive next week and so the shop and I will be starting to tear down my 69 vert. I am trying to get as educated on this process as I can. So....I have read references in the site that indicate starting from the back and working forward. I am assuming with me having to put this on a rotisserie at some point that i need to get the rear frame rails and trunk done first. My thinking has been to sure up the frame by getting the new rockers in first and then going from there with the rest....I am open to any suggestions from you guys...especially you guys who have had to do this.....thx for the help and suggestions.
 
#5 ·
If you are putting in a full one piece floor, your shop wants to tackle that first. This is a drastic critical procedure that will make or break everything you try to do to your vert afterwards.
If your shop has no experience in this, and I suspect this may be the case, then find a shop that has.

The shell has to be placed on a jig, squared per Fisher datum, and temporarily reinforced with square tubing just to start. There are pictures and threads on this. It has to be spot on square for anything to fit right afterwards. So full floor first, then rockers, everything else is cake.
 
#6 ·
I agree that a rigid jig is needed if you plan to replace the floor, rockers, trunk pan and frame rails. Only after these panels are replaced would I consider putting the convertible on a rotisserie. The unibody might buckle if a major part like a rocker panel is cut out and the car is only supported at four outer points by a rotisserie. The shop that you select should have experience with a major rebuild like you are describing and have a jig. The particular order of the parts being cut out and replaced varies. Starting from the back and working forward is just as valid as starting from the front and working back. On my project, I cut out what was the most rotten and left cutting out the semi good metal last in order to maintain rigitly of the body.

There are several build projects that describe the process of replacing the parts that you mentioned. One of them was written by 6781Camaro (Todd), another good one is being written by tjgmp (Tim).
 
#7 ·
Hi Todd. I have a 68 convertible that I am currently trying to build. I needed to replace just about everything. Keep in mind that I am only a beginner if you decide to look at my thread. I did take a lot of pictures so that might help you. I read a lot before I built up enough confidence to tackle this project. Todd has a great thread written in an almost teacher to student way. (I hope that makes sense.) Heres the link: http://www.camaros.net/forums/showthread.php?t=146455
It was great for a beginner like me to follow. Another invaluable reference is www.screaminperformance.net click on the blue convertible call resurrection. That is the road map that I tried to follow. It has great pics.

"If your shop has no experience in this, and I suspect this may be the case, then find a shop that has."-Chops
I agree with Chops. If you are paying them, they should sit down and discuss a build plan with you. good luck.
 
#9 ·
You have a little fun ahead of you. My 69 vert needed pretty much most of the items you listed. I completed it without a jig but did it piece at a time by myself. I had no previous body work experience.

Suggestions that worked for me:
Level the car and weld braces across the door frames and make an x spanning from each rear panel to the opposite side kick panel.

Measure everything, take notes and keep a level handy!!!!!!!!!!!!!!!

Keep doors and trunk lid on and adjusted.

Start with the full floor. Remove old floor but make note of the location of the vert only K brace and bolt on the X brace in if you have it. Screw and clamp new floor in place.

Move on to the Toe boards. Weld to firewall but screw to full floor.

Move onto the inner wheel houses. I removed and replaced them 1 at a time leaving the quarter and outer in place. It is a little more difficult but it makes the alignment easier. Screw in place and weld later.

I moved onto the full floor, cross rail and frame rails. I removed them all as 1 unit dropping them out keeping the quarters, tail pan and wheelhouses in place. The bottoms of the quarters need to be pulled outward so the assembly can be removed in 1 peice. Set up the old assembly on horses and use as a template to make the new assembly. I added the trunk drops later. Screw together new assembly next to old one and once all dims match weld the assembly up. Sneak the new assembly up into the car and screw in place and bolt to tail pan through bumper bolt holes. I had to use a come along to pull the frame rails tight to the cabin full floor. Once fit is completed start welding the truck floor assembly in place. Weld to inner wheelhouses, rear seat divider, cabin full floor.

I did not replace my rockers and it would make sense move onto those at this point. Others my have better ideas on when to replace the rockers but make sure you keep braces in place.

Next cut out 1 quarter at a time. Just cutting away enough at the wheel well so the outer wheelhouse can be removed. Fit outer wheelhouse and screw in place. Once set move onto removing the rest of that quarter. Carefully remove quarter keeping tail pan in place. Once quarter is fit to trunk gutter, tailpan, trunk lid, rocker, pinch weld, door and outer wheelhouse remove it and weld the outer wheelhouse to the inner wheelhouse and vert brace. Install trunk drops and put the quarter back on. Weld it up but screw to tail pan. Move onto the other side.

Once quarters are complete install new tail pan.

At this point the car went onto a rotisserie to finish welding and clean up welds.

This worked for me and my gaps turned out great!

Good luck!

Ted
 
#11 ·
I do have pics but unfortunately I have yet to figure out how to attached to this site. I can figure out most things but this seems to elude me. I can't even get my signature line to show. Oh well.

Take your time, take a lot of pic's with notes and don't open more than you are going to fix at that immediate moment. Break it up into small manageable projects. Let me know if you have any questions.

Good luck.

Ted
 
#12 ·
I do have pics but unfortunately I have yet to figure out how to attached to this site. I can figure out most things but this seems to elude me. I can't even get my signature line to show. Oh well.

Take your time, take a lot of pic's with notes and don't open more than you are going to fix at that immediate moment. Break it up into small manageable projects. Let me know if you have any questions.

Good luck.

Ted
I will definately ask questions...and you are more than ok to send picsto my email if you want....thx,todd
 
#14 ·
If you bought the plans for a jig, maybe you are planning to do the work yourself.

I am intimately aware of the jig. I built the same one. I made some minor modifications to the jig to compensate for the lack of a roof on a convertible. If you care to look at my jig, it is in the build project of this forum. The title of the thread is "1969 Firebird Convertible". The parts you mentioned that needed to be changed are identical on a Firebird.
 
#15 ·
Yes...it looks like it will work out that i will be doing aloot of the work myself as i cannot afford the body shop cost especially with a body guy that may not know as much as he should. It is ok as i do have much experience with mustang converts and i did build my 67 eleanor. This is why i think the best thing to do is go with a jig so I have a better chance of getting things right. How much did your jig cost in materials.....thx for the help.:beers:
 
#16 ·
I built my jig from plans from firstgenjigs.com . The material, including casters, hardware, etc., cost me around $600, but I had the steel shop cut all the pieces of tubing to exact length for me (they were all perfectly square, and within about 1/16" of the dimensions I requested). If I were to do the cutting myself, I would have saved around $200, but I didn't have a horizontal bandsaw and didn't want to deal with the cutting.

If you're doing the panel replacements yourself, having the jig is a huge help. I replaced one panel at a time for the most part, and the jig gave me plenty of places to support things from, as well as providing the factory alignment points as I replaced pieces.
 
#18 ·
My 69 coupe is still a work in progress. I bought it in April, and spent about 5 months replacing every piece of sheet metal other than the roof and the center of the cowl. The front suspension is now done, and my rear is being regeared as we speak, so it should be installed next week. This spring i'll start the install on an LS1 and 4L60e .

There's a build thread with pics called "69 Camaro for My Daughter" in the Build Projects forum (can't copy the link on the iPad).
 
#20 ·
Yes, I replaced the rails. I got the body set on the pins, and then tacked a few braces to the new rockers to keep it from moving. Then I was able to remove the old rails, put the new rails on the alignment pins, and welded the new trunk pan to the new rails and to the wheel wells to lock everything together.
 
#21 ·
Yes, I replaced the rails. I got the body set on the pins, and then tacked a few braces to the new rockers to keep it from moving. Then I was able to remove the old rails, put the new rails on the alignment pins, and welded the new trunk pan to the new rails and to the wheel wells to lock everything together.

X2 for me. I welded on a vertical post with a platform on top of it to support each outer rocker, while the frame rails were being installed. After they are in, weld the new trunk floor onto them, and then the trunk floor to the inner wheel wells to lock it all together. Then you can use the jig or even a rotisserie if you want.
 
#22 ·
Well, A full day put into the car today. Got the subframe/motor off and completely stripped firewall to metal. I always love when I get to see a part of the car that I hadnt got close to before and then find that I have alittle more rust than i thought. turns out that the bottom of my drivers side A piller is rusted aboout 1 inch up and the firewall toeboard area where the front subframe mounts are a little rusty as well. Other than that the firewall/cowl seems to be in pretty good shape. Do I consider myself lucky that this is all i found once i removed the subframe?...Will post pics possibly tomorrow. My jig plans should be in this week and then I can build it and get the car on the jig and start some real work.
 
#25 ·
Well just an update....worked on stripping the cowl last weekend and found that my bottom was rotted out after sub came out. So I ordered in a new firewall. This last weekend I got to work on building my firstgenjig. I will be welding it this next weekend and with a little luck I will have it on the jig before the weekend is up. After that it looks like I will start tearing into replacing the whole underbody. I am really kind of looking forward to gettin busy on it. Something about having everything new underneath that will be kind of cool. I do plan on painting the underneath the same color as the car. I did my shelby on a rotisseie and finished the underside in the same paint as the top and it looked really nice with all of the new parts next to it. Will post pics soon.
 
#26 ·
When you build the front frame that ties to the firewall, don't bother with the crossbars- they get in the way when you try to replace the firewall. I originally built the whole frame, and ended up cutting out the crossbars. If you set the body on the locator pins and build the tiedowns that go into the bottom of the rockers (where the fenders mount), the front frame isn't really all that necessary, IMO.
 
#28 ·
well guys....jig was built this weekend. I will be putting the car up on it on friday. I will be starting by repairing the lower part of the drivers A pillar. I think then from there I will tackle the left rocker along with the front firewall and cowl shoulder. will be nice to be able to roll this thing around in the shop.
 
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