Hi all,

Some of you may have seen from another thread, I'm a C5 owner who is looking into a C3.

The car in question does have some rust on the frame.

It looks superficial, but I'm low on experience when it comes to older cars. Is there a way to tell the difference between some harmless surface rust and a bigger problem? Or would you run from any sign of rust whatsoever?

Many thanks,
Jon

 

I guess it depends on what amount of work your willing to do. On my 78, the problem wasn't the frame but the birdcage. I had some rust problems to fix on the frame and needed to weld in some new boy mounts. The birdcage required removing the whole front end, sandblasting the cage, removeing and welding in new pieces of windsheild frame. The lower sections of windsheild frame are available in the after-market, so I had to make peices for both sides.
I'd so a thoughrow inspection of the #2 body mounts behind the kickplate, before purchasing another.

 

Can you post up any pics?

 

pics would help alot, if its just surface rust, its no problem to grind it off and put some rust retardent or prohibitor on it

Miles

 

Cool guys, I'll swing by with the camera on my way home today and post 'em up.

Is there a map of the body mount #s? i.e. which one is where? I've been searching but didn't find this basic info (I'm thinking everyone here already knows something this simple).

Also, I'm really going to show my C3 ignorance (please be patient) - what areas are the "birdcage"?

Thanks for all your help, it's been a great welcome for a C5 guy in the C3 forum, I appreciate it!

 

The "Birdcage" is the metal cockpit area, encompassing the windshield, T-Top Frame, floor area going back up to the storage compartments. In other words, everything that is metal except for the frame. The only way to really check without gutting the interior is by checking where the kick panels are(The plastic coverings underneath the dash on the door sides-they are underneath the vents). Remove the kick panels, and check for any chunks of rust sitting there. If the salesman isn't looking , lightly tap the metal enclosure. If any chunks of rust fall, be prepared to run!
The other areas are as stated before, the kick-ups in front of the rear wheels, and the Rocker Channels, which are the bottom door thresholds(hope that makes sense).
(I had some rust on all of these, but lucked out in that it was mostly surface rust with minimal holes that patched up easily). I can try to find some pics later of these areas if it would help you out

 

Hope this helps.

 

Here's a pic posted by another member...anyone have that great drawing from the Haynes manual (I think?)?

As mentioned above, by removing the plastic kick plate you can see the #2 body mount and any bad problems. Also, by pulling the glove box insert you can see the inner portion of the windshield frame on the passenger side.

Good luck

 

Very helpful everyone, thanks!

 

Most notorious area for frame rot is the end cap just in front of rear wheel ... and plainly visible.
Look for any repairs to this part, especially where it goes under the fiberglass.
Someone did a cheesy repair on the frame I rebuilt.
It was a cheap weld/thin steel and covered with tar.
Here is a before and after:
Before
http://webpages.charter.net/davekimt..._frame_end.jpg
After (you don't wanna go here)
http://webpages.charter.net/davekimt...amerail_14.JPG

Lower birdcage exposed and showing rust around the #2 mount.
This was solid - just surface rust.
http://webpages.charter.net/davekimt...all_split2.jpg

Another likely place to rot ... inside corner of frame just in front of rear wheels.
Almost impossible to inspect in here.
http://webpages.charter.net/davekimt..._rear_pass.jpg

Trailing arm pockets ... look for the layers of steel around the pocket
to be rusting inbetween and swelling apart (bad). This one does not have any obvious swelling in the seams.
http://webpages.charter.net/davekimt...ailing_arm.JPG

In a chrome bumper front, you want to check for the bolt-on
"batwing" crossmember ... under the radiator support area.
No pic of this ... and check the radiator support itself along
front bottom edge.

Besides lookign at the body mounts, you can check the rocker channel
integrity by sliding your fingers up between the frame and rocker channel ...
then lifting up and out. The channel should be solid. Any flexing and/or
rust falling out and the channels are bad.
Here are the rocker channels from my rotted 75: (they are not supposed to fall off)
http://webpages.charter.net/davekimt...r_channels.JPG

That should get you started looking.

 

Take a screwdriver with your camera and anywhere that you see rust, tap the frame with the screwdriver. If pieces start falling off or the frame is soft, you will know there is a problem. You might want to do this when the owner is looking the other way...

Good Luck
Chris

 

Very helpful pictures! thanks!

 

Listen as you tap the frame. A clang is good, a thunk is bad.
Glenn

 

I'd do the tapping no matter what...it might make the dealer think you know something