C3 on Jackstands
Team Owner
Joined: Jul 1999
Posts: 26,545
Likes: 46
From: Huntersville NC
verts are worse and 68s are the worst as far as flexing frames. (They lack braces that the 69s and later have) When I put my 68 vert on stands I can't open the doors if closed, or close them if open. And there were many many complaints of all kinds about these cars when they were new!! 
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by NHvette
If you jack your C3 up and the door hits/rubs/sticks
when opened and closed, you have some sort of frame and/or
body rot. Mine was exactly as you describe, and after doing
a body-off, I realized how unsafe it was.
My newly restored (solid) frame does not have these problems.
Should you open the door before jacking ? Yes, if you don't know
the condition of the frame and birdcage.
Should you have your vette looked at if it does this ? Yes.
Here are a few pics of the frame/BC that did "flex":
rocker channels:
http://webpages.charter.net/davekimt...r_channels.JPG
frame ... look at the rotted corner behind the cat converter.
When I leaned on the rear bumper (170lbs), the frame would
flex at the rear kickup area.
http://web.archive.org/web/200304190...es/chassis.JPG
when opened and closed, you have some sort of frame and/or
body rot. Mine was exactly as you describe, and after doing
a body-off, I realized how unsafe it was.
My newly restored (solid) frame does not have these problems.
Should you open the door before jacking ? Yes, if you don't know
the condition of the frame and birdcage.
Should you have your vette looked at if it does this ? Yes.
Here are a few pics of the frame/BC that did "flex":
rocker channels:
http://webpages.charter.net/davekimt...r_channels.JPG
frame ... look at the rotted corner behind the cat converter.
When I leaned on the rear bumper (170lbs), the frame would
flex at the rear kickup area.
http://web.archive.org/web/200304190...es/chassis.JPG
My 77's doors work just fine when on jack stands.
Instructor
Joined: Sep 2005
Posts: 194
Likes: 0
From: Hamilton Ontario
Here's the skinny.
From experience I have had the same problem. It all depends on your jacking and jack stand placement. Be out too much one way or the other and you will get body flex. This is normal for corvettes, and many other vehicles for that matter. It has nothing to do with the frame being weak, but pressure is transmitted to the fiberglass body.
To avoid this problem I follow these rules:
1 - ground must be level ( this is a big one )
2 - jackstand placement must be as far forward and back on the frame as you can place them, and at the same heights.
3 - if storing, or leaving the vette on stands for long periods (storage),
you will need to have support under the front end or it will sag.
Hope this helps.
From experience I have had the same problem. It all depends on your jacking and jack stand placement. Be out too much one way or the other and you will get body flex. This is normal for corvettes, and many other vehicles for that matter. It has nothing to do with the frame being weak, but pressure is transmitted to the fiberglass body.
To avoid this problem I follow these rules:
1 - ground must be level ( this is a big one )
2 - jackstand placement must be as far forward and back on the frame as you can place them, and at the same heights.
3 - if storing, or leaving the vette on stands for long periods (storage),
you will need to have support under the front end or it will sag.
Hope this helps.
Safety Car
Joined: Jun 2005
Posts: 3,775
Likes: 4
ive had my 69 vert jacked up in every possible way, includeing takeing all 4 wheels off and haveing it sit on a couple of 4x4s for about a week. never had a single problem with flexing, the doors always opened and closed just fine, along with the removeable hard top.
even had the front end up on ramps for about 3 months and again, in that entire time i never had a single problem.
even had the front end up on ramps for about 3 months and again, in that entire time i never had a single problem.
Safety Car
Joined: Jun 2002
Posts: 4,751
Likes: 2,499
From: Buckeye, AZ
St. Jude Donor '12-'13
I must be lucky or have a car that was built on Wednesday. I have had it on one jack, two; back/front, four stands windows down, windows up, T-tops in, T-tops out etc. I agree with one above. through normal servicing, tire changing, etc. wouldn't someone have bitched to GM if the cracked their car. I am thinking it is not about how they are built but maybe the age of the pieces just makes them a little more delicate than when these cars were new.
