Hi, my name is Sam and many of you know me from my major restomod build "My 1965 Rebuild" which is still ongoing. The body on my car ended up being totally disassembled so that birdcage repairs could be made. Every piece of fiberglass has been separated from the birdcage including bonding strips. I am in the process of re-assembling the body. The frame has been leveled on an alignment lift and the birdcage assembled to the frame. The bonding strips were reinstalled on the birdcage last year and I installed the doors a few weeks back. I have the doors opening and closing real nice and they are sitting in the openings real nice also. I have been working on getting all the glass and other mechanicals into the doors to account for sag while doing the rest of the body work. So far I have not had to readjust the doors but I am not done yet either. So that quickly catches you up and is where my issue / questions start.

Today I started to mockup the roof panel, rear deck panel, tail light panel, and the drivers side rear quarter panel. I have been using the grid layout from the assembly manual as reference. I have attached these for your reference. According to the grid layout the body line down the side of the car slowly slopes down from the front of the door to the rear of the car. From the front of the door to the rear of the door the line is about 5/8" lower in the rear. From the rear of the door to the rear of the quarter panel the line slopes down about another 1". My doors show the proper slope and after hanging the quarter panel on it also follows the proper slope.



In the next two pictures I have the green laser on and it is locked at the proper angle showing the alignment of the panels.


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The next picture shows my problem and is what I am asking for input on. As you can see the tail light panel is sitting about 1-1/2" too high. It is above the frame and will make it impossible to install or use the bumper brackets in their stock configuration. When I bought the car it had this same issue. I thought that after disassembling the body that I would be able to fix this issue when I reassembled it. But everything has fallen into the same position.



When I bought and disassembled the car there were a ton of shims in the #4 body mounts. There was probably at least an inch of them. I removed most of them and have two thick shims in there now. This also helped level the rear floor section. But I have had to place a 3/4" shim between the rear deck and the rear bulkhead.



#4 body mount shims



3/4" block of wood between the rear bulkhead and rear deck.

I am not sure what to do here. Everything is driven by the doors which are sitting in the opening correctly. Level at the bottom with about 1/8" - 3/16" gap at the bottom of the door and the ledge of the fiberglass rocker cover (door jam). Changing any of the shims will not make a difference with the bumper brackets because of the body line.

*Removing #4 body shims only means that I have to add a thicker shim at the rear bulkhead to maintain the body line.
*Removing or changing the rear bulkhead shim changes the body line.
*Removing all the shims will really mess up the body line.

Should I just fabricate bumper brackets that fit this situation?
Has that been done before or is it common?

Any input will help, thanks.

 

Judging by what you have done so far this may come across as an insulting question it is not intended to be that. Did you measure the frame for any possible damage when the body was off?

 

You said the frame is aligned to spec, so that leaves the body or body mounts. How many shims at body mount #3 and under the core support (sometimes called body mount #0)?

If you think about it for a minute, body mounts 1 and 3 for a coupe are pivot points. Shims under #3 raises the rear and shims under #1 lowers the rear. The doors go with the body, so as long as you keep the shim ratios correct, the doors will stay aligned. I think you need to eliminate the shims at #4 and either remove shims at #3 or add shims to #1. I would try using shims to lower the rear while keeping the rest of the car aligned. If this doesn’t work, it is possible to bend that rear frame bumper mount up, but to might run into gas tank fitment and/or filler neck misalignment issues.

 

Nope, no insult. I could have mentioned it earlier but just figured that I would wait until someone asked. I didn't want to flood the first post too much.

So yes, I did have the frame checked. When tearing into the car at the beginning I discovered that it had been crashed at least once, maybe more. There was a bent spindle at the driver's side front and the passenger side rear. I took the frame to a reputable corvette repair company. The gentlemen has been working on corvettes for I believe over 50 years now and he only works on C1s, C2s, and C3s. He has a frame jig that he placed it on. The rear of the frame was fine but he graffed on a new front section. I think that it would be hard to have a frame bent 1-1/2" and not notice it or have some type of crease that would be visible. Also the issue is uniform all the way across the back.

 

Hey Factoid, I think you may be onto something. I went outside to check. And to be clear I call the bodymounts #1, #2, #3, and #4. #1 being at the core support. I'm not sure that is correct, but that is what I have been doing.

With that, there are zero shims at #1 because there isn't a front clip yet. #2 has an 1/8" shim and #3 has two 1/8" (1/4") shims. They are in there that way because I leveled the birdcage with the frame. The center of the frame (the section under the birdcage) is level with the lift. That way I have a uniform surface to measure from. If it is not important that the birdcage is totally parallel with the frame then I could make a huge movement at the rear by removing the shims at #3 and maybe adding one at #2.

I will look at that tomorrow, thanks

 

So I removed the 1/8" shim at #2, the two 1/8" shims at #3, and the two 1/8" shims at #4. That lowered the rear about 3/8" - 1/2". I need 1-1/8" total for the stock bumper brackets to work. I started to add some shims back under #2 and had two 1/8" shims in there at one point. That was starting to get the rear close but it was also making the body line slope down toward the rear a lot and I am afraid that if I went that route that aligning and making the front clip look correct would be difficult.

 

Actually the core support mount is un-numbered. The firewall mount is no1. No 2 is on convertibles only. No 3&4 are the behind seat and behind rear tire mounts. But you are right to get the 4-corners of birdcage sitting solidly on the frame #1 and #3 mounts and then shim the core support and #4 mounts to fit. You don’t have to have shims at each mount. You might try setting the body on the #1 and #3 mounts without shims and add shims only to fill in any mount that is not in solid contact. See where that leaves the rear sitting.

 

Well, I am at a loss. I am not sure what to do and am just puzzled about how to move forward. I removed all the shims at 1, 3, and 4. Of course the body sat lower. I can bolt on the tail light panel at a point to where it is as high as it would be able to go in the bracket slots. I can set the rear deck on and make it fit. The problem is still the quarter panel and the alignment of the side body line. I shimmed #1 to change the angle of the birdcage / door to better align the body line on the door and quarter panel. I ended up with 9/16" of shims at the #1 mount (3 shims at 3/16" each). This made the door and quarter panel align very well. Well enough that I would be happy with moving forward, and that is saying a lot for me. (ODC, attention to details, etc) But what I noticed right away while looking at it was that the birdcage is very very not parallel with the frame. I mean very noticeable with the naked eye. I am afraid that if I moved forward with this, that after the decorative rocker cover was on the car later it would be very noticeable. It is so noticeable you can clearly see that the brackets for the decorative rocker cover are not parallel.

I am just not sure what to do. I do not want to start bonding panels until I am absolutely positive of the outcome. What I do here will affect the front later.

Would it be common for the body to be that far off from parallel of the frame?

 

I’m not sure I understand what you mean, not parallel to the frame? Are the frame rails under the cabin section not parallel with the birdcage rocker channels in the vertical plane? If so that would seem to be a frame body mount bracket on frame installation issue. Or possibly how the #1 mounts at the firewall were installed on the body. Is this the original frame (same year anyway)? Was the firewall also removed from the birdcage during the work and reinstalled?

Also, it sounds like you are keeping a consistently straight side character line through the doors and rear fenders. I may be incorrect in that. But I’m pretty sure that side character line/edge gently swoops down towards the end of the tail. Am I misunderstanding your post?

 

No, I mean that the rocker channel and the brackets welded to it for the decorative rocker cover on the birdcage are not parallel to the frame horizontally.

The firewall was removed and reinstalled with new body mount brackets using all the original rivet holes.

 

Yes, that’s what I was trying to say but I probably confused the point with “vertical”. I was trying to ask if the distance between the top of the frame and the birdcage channel varied significantly from front to back? And it sounds like it does. Some difference because of shim thicknesses is normal but sounds like you have quite a bit.

I re-read your first post again and i see you are allowing for the gradual fall off in the character line/peak from the doors toward the rear so I incorrectly remembered your description of that.

 

I did just now notice that you had a new front section grafted to the frame. What was the source of the front section, new or used? Could be the front (#1) body mount on the frame is not of correct height. The body bracket installed height changed at least once over the years and then I think on convertible frames it might have changed also to go from a solid to rubber mount at some point after 63/64. I think I would double check it. If it’s a little low then that would explain why the body is sitting a little high at the rear and the non-parallel issue.

 

Well this is depressing. I pulled up the frame dimensions for 1963 and 1965. In 1965 the birdcage mounts did change height. I didn't look at 1964 because it doesn't matter. 1963 has the base numbers and 1965 has the changes. You still have to reference 1963 to get all the dimensions needed. The number zero (radiator core), #1, and #3 are right where they should be. So I looked at the height of the back of the frame and the #4 mount. Well, if the front three are good then the #4 and back of the frame are 1" low. I don't understand how. I had a lot of work done to this frame and it supposedly fit the fixture that it was on which was made for C2's. But that one inch difference is exactly the problem that I have been seeing.

I am probably done for a while while I think about this. No matter what it appears that everything will have to come apart. Then either try to fix this frame again, locate another one - that will not be guaranteed, or call the Roadster shop.

I will have to convince the wife of the latter.

 

Sorry to hear that, especially at this stage. My frame was also spliced to replace the rusted rear with one of the reproduction ones about 33 or 34 years ago. I had old time frame specialist who had been pulling frames and unitized bodies and repairing frames for decades and he did a really nice job on mine. But those kind of guys are probably getting pretty scarce anymore.

One curiosity though, if your #1 and #3 frame mounts seem to check out, then the issue of the birdcage rails not sitting relatively parallel to the frame rails remains unresolved.

 

No, that was only an issue with the 9/16" worth of shim at #1. With no shims it is perfect. Which is how it was when I was measuring it today. Zero shims.

 

Well, that will take the wind out of your sails. Truly sorry for this to come to light at this stage of your build. Certainly better now than if you were any further into the final stretch. Deep breaths...if any one can get through this, you can

 

Dang Sam. That just sucks, but as said before, glad you found it now. Not sure what route I would take, but maybe someone has a frame for sale nearby and you could compare measurements.

 

OK, that sounds good. So where was the frame spliced? Were the kickups separated and re-welded to the crossmember by chance? Or the crossmember with the kickups separated from the frame rails and re-welded?

 

..are you referencing the datum points in the AiM, for body panels? On my '66, I aligned the doors to achieve the best gaps, then laser referenced those points, put my shimmed jack stands elevated exactly to the Aim specs, then went rearward from the rear door gap to the end peak, and the same method from the forward door gap to the forward points. My Aim isn't in front of me, but I'd bet that rear line drifts downward.

 

He noted in his initial post a that he was following the AIM profile grid drawing and the character peak line does gradually curve down towards the rear as shown on it. One of my posts questioned that because the picture with his laser line on the side of the body didn’t show that very well but he corrected me that his trial fitting of the rear fender panels was matching up with the AIM profile grid drawing.