Okay guys, I was under my C3 yesterday draining the oil and putting in some nice Mobile 1. While I inspected the condition underneath in more detail than ever before I confirmed my suspicion that is there is a fair amount of rust/rot on the front cross member. It's pretty bad where the coils go through the round opening and into their upper bucket. The entire cross member had varying levels of rust. The main rails running on each side of the car from fronto back look good, just some surface rust. Other areas of other cross members are so so. The front V cross member is pretty rotted out but that looks easily replaced via new ones on Zip.

So my big question is, what's my plan of action? Can I get a new front cross member and replace the old one? I guess this involves removing the whole front suspension and front clip.

or God forbid, do I do a frame swap? Does a new non-original frame take away from the "orginiality" of the car that much?

Anyway, just going through my options and want opinions.

 

Ultimately the only person that can answer these questions would be you the owner. I got the same unpleasant surprise when I bought my C3 11 years ago; the car looked like a great deal for the price from up above and since I had goo-goo eyes I went ahead and bought it. When I got it home and started looking around underneath I was more than a little startled to discover just how rusty the whole frame was. It wasn't perforated anywhere though so I just descaled the whole thing, treated it with Duro rust-killer and painted it. It's not a race car so it's perfectly safe. If I was going to fully restore the car though I'd pull the body off the frame, sandblast it and repair it where necessary. It sounds like you've got some pretty severe damage there and since the frame is the one major structural component of the car you're going to have to consider whether repairing it or replacing it is the way to go- obviously just sanding off the rust and painting it over won't be enough. If your car isn't a really rare one where originality is a huge issue then I wouldn't think that frame replacement would hurt its value in any way. Whatever you decide on there are plenty of people on this forum with a ready supply of know-how that can help talk you through the job, and once it's done you'll have a much better car, so have fun!

 

Hi Ryan,
As Birdsmith said it's hard to give any meaningful answers without seeing the frame.
To address your question of originality... If another frame is needed I'd be sure to find one that is absolutely correct in configuration. I'd then document the VIN # stamps and the change over. I really think everyone would prefer your car have a sound replacement frame over a rusted frame.
Another way to approach this would be... since there are now so many new sections of frames being reproduced you could replace everything that needs to be replaced. Depending how long the list of replacement parts gets, this could become pretty costly and you really need to know what you're doing.
So back to the question... what's your frames actual condition?
Regards,
Alan

 

With Alan, we need pictures. The front crossmember is not likely to be rusted through unless you have a major disaster on your hands, more than likely just surface rust. Again, we need pictures.

 

as mentioned, pictures would be much more helpful. On the FRAME, worst case scenario would be a frame replacement if it was that bad but usually repairing the frame with patches or replacement crossmembers will do the job fine unless the entire thing is basically swiss cheese.
We did a frame replacement on an '80 back in summer/fall of '07 for a fellow club members car and while it's a lot of work it's do-able although you will find you end up doing a lot more than simply replacing the frame, you will end up rebuilding the front and rear suspensions, replacing body mounts, etc because why would you replace worn out parts on a new replacement frame and since everything is already apart that's the time to do it so factor all that extra stuff into the budget if it comes down to a frame replacement.

On the other hand, if you are finding a lot of rust on the frame I'd start worrying about and inspecting the birdcage as much as possible. Pull off the kick panels and interior windshield trim moldings and if possible the exterior windshield trim pieces to see as much of the birdcage as possible. If the birdcage is very bad than the frame becomes a moot point since on the later year C3's the value of the car isn't enough to justify the time and expense of a birdcage replacement which is the most extreme repair you could ever have to do on a C2 or C3 Corvette.

 

Good info guys, thanks so much for weighing in. I'm going to get some pictures underneath and post them up here. I haven't checked the Birdcage but that is a great point that it's condition is key in deciding the way to go.

 

Here is a picture at passenger spring. The frame rails are good till here at the interface. The rails are even solid here but you can see the cross member is looking rough. It could just need clean up and some additional material welded over in the bad areas. I do weld, so I could do that or try to replace the whole #1 cross member. I can't say I've seen full front cross members for sale in my searches yet.
http://www.4x4tek.com/ryan/photos/ma...g2_itemId=3354
This is about the closest I've found for reparing it. Welding upside down to get this in place could be tough. I have a certified welder friend that could help me out on this.
http://www.zip-products.com/Zip/prod...2187C1BB15DC98


here is the center of that main cross member... here i think it can just be cleaned up and painted.
http://www.4x4tek.com/ryan/photos/ma...g2_itemId=3348


This is an older pic and I can't quite remember where it is.... I see a radiator hose so this must be right up front. Lots of surface rust that I could clean up and paint over..... it could be the front frame horn.
http://www.4x4tek.com/ryan/photos/ma...g2_itemId=3357
Found a replacement peice here on Zip that looks like it could repalce this...
http://www.zip-products.com/Zip/prod...2187C1BB15DC98


This is the V crossmember up front... it's thin stuff and rotted through, but I know i can replace it via a new part on Zip corvetter parts..
http://www.4x4tek.com/ryan/photos/ma...g2_itemId=3351
This is the replacement part from Zip:
http://www.zip-products.com/Zip/prod...2187C1BB15DC98


This is the crossmember where the snubber support is. I have since had this already fixed by a shop where they added new metal in to fix it. The job was okay, but ultimately I need to buy a new bracket from Zip and do it to look correct/original. In the meantime lots of the metal around it will need cleanup and paint...
http://www.4x4tek.com/ryan/photos/ma...g2_itemId=3363
This is the support that I will ultimately do to re-do what the shop did:
http://www.zip-products.com/Zip/prod...2187C1BB15DC98


Soooooo.... the rust is clearly and issue but it might be salvagable without a frame replacement I hope. What I don't have pictures of is the main rails front to back that have little to no rust on them at all... Some if not most parts of them still seem to have paint on them. I guess the crossmembers take more of a beating or aren't as well coated from the factory.

All these pics are kind of old and I need to take new and better ones. I plan to have the vette up on jack stands this winter and just start going to town cleaning and painting underneath as best I can and discovering and noting all the areas that need help.

I'll also look at the birdcage too.

 

The worst part seems to be in picture 4. If I'm not mistaken, that looks like the rad support in which case the replacement is bolt on. Not cheep, but no welding work required.

Other than that, most of the rest looks like a good welding shop should be able to take care of it.

My .02

EDIT: Oops, you added pics while I was typing. The part that I thought was a rad support sure looks like the v-crossmember in the ZIP pic. Still looks bolt on though and cheeper than a rad support.

 

It looks like there is a lot of scale showing in the holes of the differential crossmember. If you bang all over the crossmember with a pointed body hammer I'll bet that you are going to find some soft spots.



Rick B.

 

Any more opinions out there now that there are pictures?

In response to 72LS1Vette: Yeah, you are right. I plan to take my descaler attachment for my air hammer and see what is good and bad. I've got my fingers crossed.

I will replace cross members if I need to, it's just the front main cross member that holds the front suspension that doesn't seem to be sold as a replacement unit like all the other cross members, that I'm worried about.

I'm hoping that complete repair plate that is offered will be enough to shore it up after I de-scale it and see what's good and bad.

 

If that were my frame I'd pull the body and do a frame swap or have it rebuilt. I can't answer questions about originality or value, but that frame is in bad shape form the pics. My frame was bent and had some minor rust, but nothing compared to that. I had the body removed and the frame rebuilt, straightened, sandblasted, and powder coated, and now it's the best looking part of my car. Minus the incredibly handsome driver, that is. :-) Just to warn you though... depending on how you do it, it's going to cost you. I had my body removed at the mechanic and the frame shipped 200 miles away on a flatbed, and the entire project (body off, repair, straightened, sandblasted, powder coated, shipping) set me back almost $7,000. It looks freakin' cherry now.

 

The problem with having that much scale is that even if the metal is still sort of solid it probably has lost a lot of its original thickness and strength. The differential crossmember ties the whole frame together - the side rails and the rear rails both attach to it.

Since you have a 72 it is harder to find a used frame in good condition - I happened to luck out and get an excellent condition 73 frame for my 72 a couple of years ago, but they are getting more expensive all the time. If you can do the fabrication and welding yourself and have a way of keeping the geometry straight you could save some $ but you might also look into repro frames. Not inexpensive at ~$4,000 and up but if you are paying someone else to do the work the costs add up quickly.



Rick B.

 

with regards to the differential cross member I can replace that one myself completely. here is the part:
http://www.zip-products.com/Zip/prod...39B261EEEA8F26

It's the front main #1 cross member that i need to worry about and if it's not repairable then there's probably no use in doing the others. All the other cross members seem to have full replacement crossmembers available except for the #1.

I'm in no position whatsoever to spend $7k on frame work. I am in a position to spend many hours cleaning, patching and replacing crossmembers in place in my garage. Does this seem like a reasonable solution? One of my bigger questions is can I replace cross members in place. I don't think I will be able to get my welding gun up on top for welds which i'm sure the stock one has.

I guess I need to look into how I could get the body up and off the frame in my own garage and see if that is feasible.

Thanks for the feedback guys.

 

Rick, where do I find reproduction frames for sale? I haven't seen them in my searches?

 

Try Zip and Dr. Rebuild for starters. There are 1 or 2 companies that advertise in Corvette Enthusiast also. I'll look them up tonight and post the names.

There are also some more modern alternatives. SR-III has a really nice tube frame and Rowley Corvette is selling some modern re-designs of the original style frame.



Rick B.

 

These people apparently have the original GM tooling jigs.

http://www.vetteproducts.net/

 

In looking at this site they show the #1 crossmember for $129.

 

Here is the company that I saw advertising in C.E.

http://www.colliertechnologies.com



Rick B.

 

As mentioned before we would need to see pictures to know how bad the damage is. My 68 frame was a horror story. In all honesty I think the body kept the car together and not the frame. When I pulled the frame from the car It fell apart. I didn't have to cut anything. I got a used/restored frame from http://www.corvetteusa.com/. It's a great frame and may be worth looking into.

 

Unfortunatly you must pull this frame. A waist of time and money trying to patch this one on the car. The rust is always a lot more worse once you get into it. You need to check the kickup's, birdcage and channels.