Hey all,

Just got the C3 Buyer's Guide in the mail yesterday to aid me in my C3search - good stuff, but often the author simply recommends to "watch" for frame rust in the area between the doors and the rear axle.

I looked at a late '70s Vette the other day that (I think) obviously had way too much - holes in the back of the frame boxes, and when you put your fingers in (probably a bad sign to begin with!) you could feel moderately sized pieces of metal lying there in the bottom.

I'm wondering, however, is any rust (other then the obvious surface oxidation) ever okay? Maybe this is a dumb question, as frame rust just sounds like a no-brainer, but being in New England, I don't want to go nuts looking for perfection when I should have settled for good enough, especially since this is such a common problem on C3s. Thanks!

 

I'd say it depends on how much the seller is asking for the vehicle and how much money and time you want to spend on the project. Frame rust as extensive as you describe will be very expensive to fix in terms of money and labor. Probably a new or donor frame if it's as rusty as you describe. Other concern is the birdcage. If the frame is that far gone the birdcage may also be in poor condition. That can be VERY expensive to repair. I doubt such extensive repairs would be affordable unless you can do most of the work yourself.

Some surface rust is expected. If you are finding holes, the project begins to get expensive.

I live in the New England area. You should be able to find another in much better condition if you're patient. It would not be unrealistic to hold out for one without holes in the frame. Depends on how much you want to spend up front vs how much you want to invest after purchase. The project always ends up being bigger than expected.

 

Rust on the kickups behind the doors seems to be standard fare on many of the New England frames I have looked at and that can be manageable if it's confined to that area. Unfortunately, it's usually the tip of the iceberg and gets up over the rear wheels and across the area around the rear end. Before you buy an old Vette from the rust belt, make sure you get it up on a lift or you may have many "surprises" when you get it home, and then it's too late.

 

Thanks for the advice, so it sounds like I'm on the right track. As for the car I looked at, the seller's bottom line was the most I was willing to pay BEFORE I saw the holes in the frame, so that seemed like a lot to take on for a high mileage car that also had other issues.

BB mentioned the birdcage, which brings me to a similar question as the frame issue - at what point do you write off a birdcage? - I have tried to check these out by doing the common sense stuff - looking underneath the weatherstripping, removing t-tops, and removing the interior kick panels.

The inside of every kick panel has revealed at least some rust - either small chunks, or at least some amount of rust scale that has settled in the bottom, and looking under the weatherstripping has always shown at least some surface rot. Is this just another part of New England Vettes that you come to expect, or should I be headed for the door? Are there better ways to check for deterioration?

 

You'll probably find surface rust on most birdcages. I would look for holes or large chunks of rust behind the kick panels, around to body mount. If you have a digital camera, maybe take a picture up inside the door pillar with the kick panel off. This may show you some areas which are tough to see on the outside. Not a guarantee if the rust isn't extensive.
Other common areas are the windshield pillars. Look through the glass at the metal where the glass meets the lip. Rust will sometimes show here as swelling of the metal when the rust is between layers of metal. Check the moldings around the windshield, any sign of owner added RTV is a red flag. Look at the bottom corners of the windshield frame.
If possible, ask the owner to remove the windshield post covers, only one screw I think.
Look at the header where the screw fastened the pillar cover.

Other areas are the front body mounts and #3 mount in front of the rear wheel. The #3 mount can be seen by removing the cover in the wheel well.

Last but not least you may try to check the rocker channels using a mirror. Not much room there with the body in place.

Extensive rust in the forward portion of the birdcage may require removal of the front clip and firewall to gain access to the parts which need fixing. The front clip is glued on, not easy to remove. If the rust is limited to the mid to upper windshield frame the repair may be done without taking the clip off. Rust in the lower sections, rocker channels or body mounts will require removing the body from the frame.

The point at which you walk away depends on what you're willing to spend, time and $$.

If you do a search on Corvette birdcage rust, you'll find many photos and narrative from people who have fixed some pretty awful cases. It would give you an idea of what to look for and what's involved in fixing the problem.

 

What's the "most you are willing to pay"..........perhaps rust issues will be part of the package on almost every car, and you might want to consider upping the ante a bit to avoid that ?

I don't know if this is your first Vette, but IMHO perhaps paying $3-5K more upfront for a really good rust free car, versus accepting $3-10K (or easily more) of rust repairs on every prospective purchase, certainly makes sense to me. One thing I learned from reading this forum for the last 10 months is that when buying a car, buy cosmetics over mechanicals, as it is really easy to become upside down due to bad cosmetics (bad paint/bodywork/rust repairs) than it is on mechanical repairs.

 

This is about all I'd want to deal with again:



I had to replace 2 feet of frame rail in front of the kick-ups, replace #'s 3 & 4 body mounts on the frame,
repair #'s 2 & 3 mounts in the birdcage, repair the windshield frame in three places
and replace the under body reinforcements.

Surprisingly, the cost was not that much.
We did the work ourselfs and spent about $750 in parts & materials on the frame/birdage repairs.

Here is the same tub after the repair with a few dollars added to the bottom line:

 

RTV is a red flag? The stuff that was originally used will rot and need replaced at some time or other, and in order to keep water out it needs replaced, most just guys use black silicone. Not a red flag at all if the windshield is original. but rather very common on most older cars with original windscreens. Other than that your write up is dead on.

 

I mention RTV, referring to any kind of silicone sealer which has been applied to the moldings. Generally a sign of a leak which some owner didn't want to or couldn't fix. I'm dealing with some of this now. The channel between the edge of my windshield and the frame was filled with black RTV silicone. Found some rust issues, nothing too extensive so far bit it's going to need some repair. The material the windshield rests on can remain pretty flexible for many years. On mine it's still pretty soft and sticky. Maybe, if the sealer were applied as a precaution, it may have been effective. I'd worry it was put there to hide a problem rather than prevent one.

 

Looks like some beautiful work you did there. Impressive. Two feet of frame replaced? Wow... As a few of us have said, much depends on how much work you can do yourself and how much the seller expects to get for the vehicle.

BTW: Where did you find issues with your windshield frame? How did you fix them? Donor parts, new, or fabricated? Did you check the area just below the lower windshield corner where the bonding strip meets the surround panel. I've seen photos of rust starting here and traveling under the fiberglass. Only way to access this area is to either cut away the fender and surround in the area or remove the front clip. Removing the front clip and firewall involves a lot of labor.

I'm sending mine to a shop for repair in a few weeks. I don't have a welder, prefer to let someone who has fixed this area before take care of it. Shop owner said it didn't look bad but need to remove the glass to be sure. I've done most of the other work myself, frame off, etc.
A LOT of time and $$...

 

On the windshield frame, I had to weld patches into both corners and one small patch near the middle.

I got lucky with the bottom of the frame. No rust there so I didn't have to pull the clip.

Don't pull the clip if you don't have to.

Good luck!

 

Thanks BB, good to know that this isn't an all or nothing situation, I will try some of those suggestions when checking out other cars.

10caipirinhas - Yes, I agree with you, and may very well start looking upwind for a better car. I don't mind starting out with the lower price cars because 1: it makes you really appreciate a good car when you see it, and 2: unfortunately, from what I've heard, you'd still better know your stuff if an unscrupulous seller has been "creative" in covering up problems, regardless of asking price.

 

You've got your head screwed on straight !!!

Once you've seen 20 POS cars you'll know when to write the cheque on the spot.