Lifting a T-Top C3.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 7,362
Likes: 2,281
From: Central Maryland
Lifting a T-Top C3.
Hi all,
A quick question for you C3 gurus from a C4 guy:
I recently had my girlfriend's '81 in my garage, and lifted the left side of the car with a floor jack centered fore/aft on the frame rail. I didn't open the door, or remove the T-Top panel. My girlfriend expressed a bit of concern that raising the car this way was somewhat risky from a chassis flexure standpoint (could fracture some fiberglass). With a ragtop, I would have had the same worries, but with the structural suppport of the T-bar on her coupe, I saw no such risk.
Obviously, in the future I'd prefer to avoid any risks, and to keep my girlfriend's mind at ease about this. Do you guys recommend opening doors and/or removing T-tops when lifting a C3 coupe in this manner?
Thanks for all advice.
Be well,
SJW
A quick question for you C3 gurus from a C4 guy:
I recently had my girlfriend's '81 in my garage, and lifted the left side of the car with a floor jack centered fore/aft on the frame rail. I didn't open the door, or remove the T-Top panel. My girlfriend expressed a bit of concern that raising the car this way was somewhat risky from a chassis flexure standpoint (could fracture some fiberglass). With a ragtop, I would have had the same worries, but with the structural suppport of the T-bar on her coupe, I saw no such risk.
Obviously, in the future I'd prefer to avoid any risks, and to keep my girlfriend's mind at ease about this. Do you guys recommend opening doors and/or removing T-tops when lifting a C3 coupe in this manner?
Thanks for all advice.
Be well,
SJW
Race Director
Joined: Dec 2003
Posts: 14,150
Likes: 937
From: Fremont Ca
2022 C4 of the Year Finalist - Modified
I think there is a jack pad at the front of the car under the bumper at the bumper support but I could be wrong,I do know the car seems like it wants to bend in half once you start raising it.
Melting Slicks
Joined: Jul 2005
Posts: 2,545
Likes: 3
From: 406ci SB, AFR 180 Heads - 490 HP @5,600 RPM 529 lb-ft @ 4,100 RPM
I've never had a problem with our 79, (which is close to your 81) never open the doors or remove the tops. GM didn't mention anything in the owners manual, and they built it. My 0.2
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 7,362
Likes: 2,281
From: Central Maryland
Originally Posted by Easy Mike
I recommend using only the factory preferred jacking points. Why take the risk going another way?
A lot of C4 owners heave one side of their cars up with a jack amidships on the frame rail, and as you know, C4s have no T-bar. I could see no reason to not do so on the '81, with the T-bar providing so much structural strength to the car.
Be well,
SJW
Racer
Joined: Aug 2000
Posts: 434
Likes: 3
From: Cleveland Ohio
I jack my 76 almost every weekend to change to my hoosier race tires.
two tires at a time. Been doing this for eight years no problems.
With a good frame jacking in the middle to get both tires off the ground is no issue. Doors open or closed. T-tops in or out. The C3 frame is the structure that the body rest on. Now c4's are made different. The structure is incorporated in the body.
The problem comes when you have a rotted frame.
two tires at a time. Been doing this for eight years no problems.
With a good frame jacking in the middle to get both tires off the ground is no issue. Doors open or closed. T-tops in or out. The C3 frame is the structure that the body rest on. Now c4's are made different. The structure is incorporated in the body.
The problem comes when you have a rotted frame.
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
This question has come up several times before on this forum.
I have been jacking my 68 up since 1972 and I never worry about opening doors or removing t-tops.
If the car is so flexible that it will bend, you have bigger problems i.e. rusted out frame.
I have not experienced any flexing when jacking my car up from the front or the sides. If memory serves me correctly, the previous discussions on this topic all reached the same conclusion that jacking should not adversely affect the car in any way unless your frame is badly rusted. In addition, I agree with you that the t-top structure should provide additional support rather than make it more susceptible to flexing.
My 2 cents,
Kurt
I have been jacking my 68 up since 1972 and I never worry about opening doors or removing t-tops.
If the car is so flexible that it will bend, you have bigger problems i.e. rusted out frame.
I have not experienced any flexing when jacking my car up from the front or the sides. If memory serves me correctly, the previous discussions on this topic all reached the same conclusion that jacking should not adversely affect the car in any way unless your frame is badly rusted. In addition, I agree with you that the t-top structure should provide additional support rather than make it more susceptible to flexing.
My 2 cents,
Kurt
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Melting Slicks
Joined: Nov 1999
Posts: 2,461
Likes: 354
From: Madison Alabama
This topic - open doors/pop tops prior to jacking the car up - comes up now and again...I maintain that something could happen and therefore always leave the doors slightly ajar and pop the tops, leaving them in place just have the tension removed.
Others state that if this was a problem GM would have mentioned it in the owners manual and you would break a top due to body flex going over speed-bumps.
In the end I believe it falls into the ounce of prevention category - my tops are still in one piece and as they aren't making them anymore I'll keep doing the above.
Others state that if this was a problem GM would have mentioned it in the owners manual and you would break a top due to body flex going over speed-bumps.
In the end I believe it falls into the ounce of prevention category - my tops are still in one piece and as they aren't making them anymore I'll keep doing the above.
Pro
Joined: Dec 2005
Posts: 675
Likes: 0
From: Kinzers. PA
I woudlnt worry, i have a 78 and i have it sitting on 4 jackstands. The entire car is up and its been up on jackstands for 2 months now and no problem....
I had one side jacked up for a week then put the entire thing up, im comfortable if i had to sleep under it, and i had no problems with fiber glass.
EXEPT my passanger side door i keep open because the frame is twisted a bit and the right side is down a little bit but no worries.
I had one side jacked up for a week then put the entire thing up, im comfortable if i had to sleep under it, and i had no problems with fiber glass.
EXEPT my passanger side door i keep open because the frame is twisted a bit and the right side is down a little bit but no worries.
Melting Slicks
Joined: Sep 2002
Posts: 2,390
Likes: 2
From: New Castle DE
I jacked up the 74 this weekend from under the rear before setting it on jackstands. Didn't even realize i had left the door open 
went to shut it very gingerly and noticed that there was no difference shut like every other time same gap no binding. 
went to shut it very gingerly and noticed that there was no difference shut like every other time same gap no binding.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Only trouble is if frame and/or birdcage is rotted.
If you don't know for sure, then you should release
the glass TTops - all else should be fine.
If you get cracks in the fiberglass from jacking, you have
much bigger problems than cracks in your paint. Fix the frame.
If you don't know for sure, then you should release
the glass TTops - all else should be fine.
If you get cracks in the fiberglass from jacking, you have
much bigger problems than cracks in your paint. Fix the frame.
Drifting
Joined: Nov 2004
Posts: 1,971
Likes: 7
From: Longwood Florida
My father always told me to release the latch on the tops... and open the doors depending on what type of lift was used.
I can say my car has low miles 69K.... And i got a few spider web cracks in the outer corners of the short back glass....
for all you 68-77 guys out there.
BUT... TRUE C4s dont have anything like a real frame that the C2-C3 models have.
I can say my car has low miles 69K.... And i got a few spider web cracks in the outer corners of the short back glass....
for all you 68-77 guys out there.
BUT... TRUE C4s dont have anything like a real frame that the C2-C3 models have.
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Holley505,
Like NHVette said above, Check your frame, you may have bigger problems than you realize. Your car shouldn't flex.
Think about all the lawsuits GM would have if these C3 frames really were so fragile that they flexed when you jack up the car.
Like NHVette said above, Check your frame, you may have bigger problems than you realize. Your car shouldn't flex.
Think about all the lawsuits GM would have if these C3 frames really were so fragile that they flexed when you jack up the car.
Drifting
Joined: Jul 2005
Posts: 1,891
Likes: 2
From: Baltimore MD
It's amazing to me how this keeps coming up over and over again. Some of you guys seem to think the C3 sits on a rubber frame or something. The frame under the C3 is an independant frame - true and it's actually stiffer than the C4. The C4 flexes more when the top is off! This thing about the T-tops off and the doors open - ever watched the dealership? Don't you think if this was an issue - word would have gotten around to the dealerships to follow this procedure? I've never heard a word by GM on this subject. They tell you how to jack the car up in the owner's manual. Nothing about taking your tops off or opening doors. The truth of the matter is, this - these cars don't flex like a rubber band - jacking one side up isn't going to break you t-tops or throw your doors out of alignment.
THIS IS AN OLD WIVES TALE - MUCH LIKE AN URBAN LEGEND IN MY OPINION.
THIS IS AN OLD WIVES TALE - MUCH LIKE AN URBAN LEGEND IN MY OPINION.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by IrishJoker
It's amazing to me how this keeps coming up over and over again. Some of you guys seem to think the C3 sits on a rubber frame or something. The frame under the C3 is an independant frame - true and it's actually stiffer than the C4. The C4 flexes more when the top is off! This thing about the T-tops off and the doors open - ever watched the dealership? Don't you think if this was an issue - word would have gotten around to the dealerships to follow this procedure? I've never heard a word by GM on this subject. They tell you how to jack the car up in the owner's manual. Nothing about taking your tops off or opening doors. The truth of the matter is, this - these cars don't flex like a rubber band - jacking one side up isn't going to break you t-tops or throw your doors out of alignment.
THIS IS AN OLD WIVES TALE - MUCH LIKE AN URBAN LEGEND IN MY OPINION.
THIS IS AN OLD WIVES TALE - MUCH LIKE AN URBAN LEGEND IN MY OPINION.