Jacking up a C3
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
I'm Batman is totally correct.
If there is enough flex that the doors won't open/close,
hood jams and Ttops crack ..... Your frame and/or birdcage is toast.
In this case, a thorough body-off resto is in order.
Been there - done that - still going about 6 years later .... but now my
vette is new again.
I can't believe I actually drove it in prior condition at triple digits
Jacking on the front crossmember ... more cosmetic issue than anything else.
When restoring my frame, I added a nice reinforced plate to jack on.
Use the recommended points to place the jack stands.
If there is enough flex that the doors won't open/close,
hood jams and Ttops crack ..... Your frame and/or birdcage is toast.
In this case, a thorough body-off resto is in order.
Been there - done that - still going about 6 years later .... but now my
vette is new again.
I can't believe I actually drove it in prior condition at triple digits
Jacking on the front crossmember ... more cosmetic issue than anything else.
When restoring my frame, I added a nice reinforced plate to jack on.
Use the recommended points to place the jack stands.
Nice front plate...I thought about adding one based on earlier pics you posted, but I've never had the frame upside down.
Melting Slicks
Joined: Aug 2000
Posts: 2,964
Likes: 0
From: Huntsville AL
CI 2-3-4-5-6-7-8-9-10 Vet
St. Jude Donor '09-'10
It's not going to flex unless the frame and/or birdcage are in marginal condition. If I was jacking up a car and it flexed like that, there's no way in the seventh circle of hell I'd drive it again until some major repairs had been accomplished. Snapping a car in half on the freeway doesn't sound like much fun. 
I haven't had any flexing with mine in the last 25 years. I can open/close the doors with just one corner up.
Drifting
Joined: Oct 2007
Posts: 1,458
Likes: 1
From: Collinsville MS
St. Jude Donor '08
I put mine on jackstands by putting a jack on the front crossmember and another on the center plate of the rear spring. One of the resto books I bought recommended this way. Am I screwing up the rear spring by doing this? It has worked fine in the past but I dont need anymore unwanted problems...?
Drifting
Joined: Dec 2004
Posts: 1,345
Likes: 3
Please don’t jack up the car using the front cross member. There are reasons why and SAFETY comes in to my mind as the number 1 reason. Another reason is the center cross members bottom plate conforms to the outside radius of the cross member and is of light weight metal. You can tell right off if a car has been jacked up from this location as the metal plate material is deformed in shape.
Brian
Brian
It only deforms once, and if yours is already flattened there is no harm in jacking it there. I have done it HUNDREDS of times in my car's past 145,000 miles with me.
If the cross member is not deformed I would agree not to jack it there to keep it looking right.
3rd Gear
Joined: Oct 2007
Posts: 3
Likes: 0
From: Winnipeg Manitoba
Queezy feeling
I just jacked up my 76 and placed it on stands as per GM. Got that sick feeling in my stomach when the doors wouldn't open or close very well. I knew there was some frame issue but was being optimistic. Having just read this complete thread about frame problems and flex I think I'll just go puke.
Drifting
Joined: May 2007
Posts: 1,491
Likes: 2
From: North Royaton Ohio
Only have (2) jackstands so I put double 6x6s up front and the stands in back. The 6x6s also serve to hold my pool cover down so theyre a little long and a bit of an pain to make sure tripping is held to a minimum - but they also serve to keep the coffee cup off the floor and aplace to set the tools.
