C3 Windshieldpillar rust

[Yves Thaens]

Hi,

I have a 79 here with rust in the following spots :
- hole in the top right corner
- small holes in the lower right corver
- center outer steel section behind the dash is corroded
- left top and left bottom corners are corroded but no holes
- base of pillars has rust where body mount sits.

I know these are very difficult to repair. Can I just leave it like it is. The car is only going to be driven in summer.

Thanks

Yves
Belgium

[Mike M.]

Re: C3 Windshieldpillar rust

cut out rust and mig-weld patches. it'll only grow like a cancer if not repaired. good luck, mike

[Jack H.]

Re: C3 Windshieldpillar rust

In addition to what Mike said (cut out rust and make weld repairs), consider 'bathing' the entire inside of the windshield surround with a rust arresting paint to halt the progression of the 'cancer'...

What you've found is a pretty common malady on Shark cars typically caused by a prior owner's improper windshield replacement effort. If the replacement glass is properly positioned and the appropriate sealant materials applied, rain water will be driven to the upper corners and seek a migration path into the car driven by the wind.

Eventually, the water succeeds in eating holes through the windshield surround portion of the birdcage which is hollow inside. Invading water will travel up and back (can also enter the T-Top center bar, and run down the windshield support uprights and 'puddle' onto the the top of the frame doing more damage as time passes.

Bottom line: (1) stop the existing rust, and (2) plug the existing holes before you wind up with a real mess--a full bird cage transplant from a donor car. That's NOT cheap and it's an ugly job...

[Yves Thaens]

Re: C3 Windshieldpillar rust

Jack,

Thanks for the advice, but what I'm thinking is that any rusttreatment is ok, but I don't think that it is possible to treat the intire birdcage in every place. So this would leave a lott of rust untreated and this would finally rust the backbone out of the body.
I've seen cars where eventually the doors would fall out. You don't want that to happen to an fully restored car.

Is a birdcage transplant an option ? That is, if you have a birdcage at your disposal. This would leave the option open to have it treated with zink/powdercoating and get a ruststopping process even on the inside of the birdcage where one can never get with rusttreatment.(That is what they said a zinklayer on the outside would do...)

However, the process of transplanting every fiberglass part would indeed be very messy and a big job. I do not take the cost into account if you can do it yourself, just for the love for the car. Nor do I take the houres into account. Thing is, the job would have to be done...that is where I get my doubts.

BTW : I live in Europe, which makes these cars even more diserable than in the US (and worth more)

Yves

[Jack H.]

Re: C3 Windshieldpillar rust

Yes, a bird cage 'transplant' IS possible, but it's a HUGE job! Most identify those areas of their existing cage that're badly rusted and HOPE the individual sections are in places where fiberglass body panel components are NOT bonded on! Then, they acquire a replacement bird cage from a donor car Corvette that's been EXTENSIVELY stripped for parts (figure a $300-800 item Stateside from a Corvette scrap yard) and start the laborious process of measuring, cutting, transplanting the individual sections and welding the new onto the existing....

On getting a 'stop rust' additive inside your existing bird cage, it's not as difficult as you imagine. There are flexible wand attachments for spray guns that are designed to get inside frame/chassis components for doing just this kind of job and/or spraying undercoat material there. In the end, if you're not too badly rusted (assess by tapping here/there and listen to the 'tone' of the ringing metal of the bird cage), that's a LOT cheaper/faster than doing a full bird cage transplant!

The time/cost of peeling the nose of the car off the bird cage, gutting interior components and wholesale replacing key bird cage sections is SIGNIFICANT! Plus, being in Europe, you're also staring at a pretty healthy cost to locate a donor bird cage that's reasonably rust free and getting it to you...

[Yves Thaens]

Re: C3 Windshieldpillar rust

Jack,

Ok, that said :
I'm looking at a birdcage of a totalled car, which is in very good shape (ex-californian car). It still needs to dismantled. I can easily get it here myself.

About the tapping part : I used a screwdriver to do this... the top left corner had a hole in it. I tried to weld it with some new steel, but it was difficult because of the already thin material that was stil left,it kept on melting away making the hole bigger. I finally patched this part up, but this was still the easiest one.

I have punched some wholes in the lower corner on the same side. This seems impossible to repair without taking the front clip off completly (which is half the car). If I do this, there is still the firewall to work around and as I can see in the AIM this section goes unterneath it.Taking the firwall of the car leaves only the rear end to be removed to do a complete transplant.

And there is more : the small reinforcement steel plate that is under the nr 3 and 4 bodymounts (inside the pillar) is completly rusted away on the bottom. From the underside I can't see any rusted through spots on the side rails and they sound healthy when tapped.

To be honest : as a very good job, a complete birdcage transplant would give best long term results, but especially the rear seems like a huge problem to transplant. It will only come of, when the pillarpanel is sawn through and the top hoop is taken out. Then I would still have to align the whole thing, which is going to be a pain I guess.

Thanks for your already big advice.

Yves

[Jack H.]

Alas...

after reading your more complete description, you begin to understand why there are some Shark cars for sale at 'bargain' prices! From what you tell me about lower end of the front bird cage uprights, I think I've got some more 'bad news' for you...

I suggest you poke/probe/look at the portion of your existing bird cage that runs beneath the door sills and sits atop the center section of the frame. If water puddled and created as much rust/rot as you describe in the lower front section of the bird cage uprights, it probably didn't stop there and flowed backward along the cockpit's outer sill plate segments too...

This kind of damage can make for a 'delicate' body lift should you decide to go frame off to repair the damage. I've seen Sharks turn to 'dust' beneath the doors and try to fold, tip to tail, during body lift...

[Chuck R.]

Amen to that Jack

I was ready to tear into my 68 cage and replace the entire front cage assembly until I lifted the body off and got a good look at the sills too. I could pull them apart with my fingers.

If it wasn't for the fact that I left the doors on the car, I know for a fact that I would have broken it's back had I lifted it without the doors in place.

With that said, I was able to purchase a pristeen rust free body from Colorado for what I know was at least half of what I would have spent in materials and more importantly time patching up the existing hulk.

Like I've said before, I hate giving up on anything, but this one was a no brainer for me.

Carving the glass away from the cage alone will take many MANY hours of tedious hand work to ensure that the bonding strips aren't mangled and can be re-used.

But hey, it's your ride, time and $$ Do what turns you on.

Regards,

Chuck