I bought this 72 Convertible back in December and have spent the last few months disassembling it. For a car almost 35 years old, the frame and birdcage are in suprisingly good shape but I did find some minor rust in the windshield frame that I am currently in the process of repairing. I am replacing the windshield frame top, top corners and sides with a brand new pieces from Paragon Reproductions. I also cut out the bottom corners along the factory welds and panels and am replacing them with good panels from a donor frame I bought off of eBay.

Luckily, the rust damage is limited to this area and the rest of the birdcage is in excellent condition. The body mount pockets located behind the kickpanels are an area that is commonly rusted out but mine are in great shape. I was able to remove all the body mount bolts on both sides of the car with very little effort. I have already fabricated a pair of body braces to prevent the body from flexing, cracking, and possibly breaking when I remove the convertible body from the frame. I cut a piece of 1"x1" square tube mild steel to fit each door opening, bolted each piece to the top door hinge receiver flange, and welded a tab onto the other end of teh tube, and bolted it ot the door jamb striker bolt retainer. This effectively ties the two ends of the birdcage together and will prevent it from breaking under it's own weight. I already bought a body lift kit and will rent a 2-ton hoist as soon as I am done with the windshield frame repair.

The Damage:

 

The Repair:

 

Prior to cutting out and replacing the windshield frame itself, I welded several pieces of steel tubing and rod to the body brace I installed previously. I welded two pieces of steel tubing to the windshield top frame to support it in place while I removed the sides of the frame. I also welded two pieces of steel rod to the body brace angled up to the top corners of the winshield frame in order to provide a reference for the windshield frame rake and width. Additionally, I took several measurements of the original windshiled frame to ensure that the new frame is dimensionally accurate and located porperly in relation to the rest of the car. While there is some tolerance between all the individual panels, windows, doors, etc, accuracy will ensure a proper fit and reduced wind noise and water intrusion. Regardless of all of this preparation, needless to say, I was still nervous about cutting out the windshield frame.

In order to determine where to cut the side frame, I measure the length of the replacement frame and compared it against the original frame. I determined that the cut should be made 19 1/2" from the top corner of the frame. After marking the location of the cut, and taking a deep breath, I put the Sawzall to work.



After preparing and cleaning the area and the replacement side frame for welding, I carefully located it in position based upon the measurements and braces I had previously made. The new side frame is supported by the braces and magnetic welding supports.


I tacked the side frame in place with my TIG and verified that it is positioned correctly. At this point I only tacked it enought to support it firmly, but not enough that I couldn't make adjustments to it if necessary as I continued along with replacing the entire frame.


Next, I moved onto the right side of the car and repeated the process...

 

Then I installed the windshield frame top pieces. Based upon my previous measurements, the original frame inside top corner was 19 1/2" high compared to my reference point, which was the cut line at the bottom. Again, I tacked them in place with my TIG after carefully positioning and clamping them in place. When the new windshield frame is fully in place I will spot weld all the pieces together, replicating the factory welds and assembly of the frame.




Finally, just to verify everything looks like it's accurately in position, I test fitted the lower corners I cut from the donor frame. Pardon the slight surface rust, it's just from cleaning the garage floor with the water hose. Everything will be recleaned and painted with POR15, inside and out before everything is done.




With both sides and top corners in place, it's time to replace the rusty frame top with the new one....hopefully tonight.

 

Wow, Impressive, keep the pics coming

 

I'm about to start down this road as soon as finish with the floor pans. Your pictures are incredibly useful! Even after hearing lots of good advice, seeing exactly how and where you set up your braces is absolutely invaluable. Thanks a 1 X 10^6!

 

Boy are you an optimist. When you said that the frame and birdcage were in pretty good shape for a 35 year old car i pictured something entirely different.

It looks like an excellent repair and a real professional job. If you had to have that done on the outside the cost woud have been prohibitive. Congratulations, many an owner would have walked away from that project.

 

The rest of the birdcage is practically spotless, the original paint and upholstery adhesive still covers almost all of it. There's a little bit of surface rust in the #2 body mount pocket, no pitting and nothing near as bad as the areas of the windshield frame. A little sand blasting followed by POR15 and it will be as good as new, and for $500 and a few hours of work, I'll have a completely brand new windshield frame and a very good condition birdcage. I probaby could have gotten away with just replacing the top center of the frame and the lower corners, leaving the two sides and two top corners in place as they only had minor pitting, no holes. But I figured I might as well do it right and never have to worry about it again.

After I finish prepping it inside and out, I or any future owners should never have to worry about rust. It will be rustproofed alot better than it was from the factory.

But admittedly, if I did have to have someone else do the work it would have probably cost 2-3 times as much.

 

Wow - good pictures information!

 

Very nice work there Monty houstonvett

 

DAMN dude, you do SO nice work, now could we just get you to do more OF it???

seriously good job....

seriously envy too.....


GENE

 

Thanks guys. I''ve noticed there seems to be a birdcage or windshield related thread here or in the C3 General section every few days, so I figured I'd document it as I went along.

Unfortunately it's taken me too long to get to this point, more than a month since I identified the issue - although I spent awhile debating my approach in my head. Once I get the top of the frame in place - I was hoping tonight but it ain't looking that way - I'm ready to pull the body and work on stripping the chassis. That shouldn't take long and once I get it dipped and powder coated I should have a roller by Memorial Day.

 

I've been saying the same...i'll have a roller then and then... still hasn't happened (although I'm real close now...) once you start pulling stuff apart things keep adding to the "to do list" ...good luck to you..hope you pull it off

 

Memorial Day? Oh, I meant LABOR Day. just kidding...

When I said "roller" I meant a frame with a front and rear suspension and 4 wheels. Nothing else implied or infered, LOL. I can get that with a call to VBP and a few days wait for the UPS man - you gotta learn how to hedge your bets a little better. With that said, I guess there's the possiblity you could bring this thread back up at the end of May and make me eat crow. After seeing those aluminum a-arms from Speed Direct, I may wait it out and see how they turn out. It's going to take me until the end of the summer to get my engine done (minus TT system) anyway.

BTW, your problem is you keep increasing the scope of your project. You've had your engine done pretty much since I finished my first TT. Now you've got wildass suspension, brakes, tubular frame, etc. Just get it finished, drive it for the summer, then do the next project over the winter.

 

I had it finished once before..then someone rearended me...and this happened..if I settle w/ what it is now and finish it I'll be redoing it in a couple of years and it'll be apart for 2 decades I've increased the scope about as far as i can, the only thin I could change is the rear susp. to double a arm and a champ center section but I'm going to forget about that for now

 

Mine is rusted but it is jsut to much work to do all that.

 

Suuuuuuure....

I didn't know it got rear-ended, sorry to hear about that.

 

it wasn't that bad, mostly fiberglass damage..the enersorbers in the rear did their job I replaced the rear bumper and started stripping the paint to repaint it, then I noticed the pass side door hinge had play, removed the door...noticed the front clip was separated in some places so I decided to pull to see if I could get it off and half the thing came loose..then I discovered my crumpled bird cage in the # body mount area..damn had to pull that apart...cleaned the firewall and discovered a lot of cracks...the rest is history

 

Been there, done that. Now I'm doing it again... I guess we never learn.

 

Wow Monty, that is truly professional work. I remember when I first read about checking the "birdcage" when buying a car. Wasn't sure what it was. I'm sure your post will be helpful to many for a long time through searches for "birdcage". Excellent post!