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1949 cadillac convertible body sag

Started by Mrstude, September 03, 2019, 04:42:56 PM

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Mrstude

I am working on a convertible. The window gap at the top of both rear side windows is real bad. I tried several times to adjust the convertible frames but nothing really helped. Do these cars have a problem with body sag as they age. If I jack up the car just in front of the door opening, most of the problem is corrected.

Bobby B

Car has a full frame, so what's going on here? If you told me it was a unibody like a vintage Mustang, I can see where you're heading. Where are you jacking it, and do you see the door gaps change as you jack it up? What's the difference when it's on the ground vs. up on jack stands? Are the body mounts shot causing it to Flex? You need to get under there and investigate. Something's going on if you say the gap changes and the window can't be adjusted. The '47 does does flex some when on Jackstands. Remember, there is no roof and no posts, so there is some flex going on there. You can definitely tell the difference driving the same model coupe vs. convertible. Good luck!
                                                                                            Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

Mike Josephic CLC #3877

I agree with Bobby.  A convertible will always
have some minor flex (compared to a closed car)
when using a floor jack or put on jack stands.

However, what you're seeing may indicate a serious
problem.  What is the condition of the frame?  Is it
badly rusted or was the car at one time in an accident? 
Are the body to frame mounts shot?

The shop manual gives precise measurements as to
the position of the frame cross members, etc.  Better
have a look at that and spend some time under the car.
Or -- have a pro take a good hard look at it if you're
in doubt.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Caddy Wizard

#3
Hold on a minute, Richard!  Please post pictures of the window gap.  Reading your original post carefully, I discern that the gap is between the top of the rear quarter windows and the rubber weatherstrip on the convertible frame. That sort of gap can be caused by the windows not being adjusted correctly, or by the top not being adjusted correctly, or some combination of the two.  There could also be a problem with the folding top frame or the rubber weatherstrip. You have NOT said that the gaps around the door where it meets the body are poor. 


My guess is that the link plate (not sure of the correct name) in the well needs to be adjusted one way or the other, which has the effect of lowering or raising the middle of the folding top rail.  Once you get the top adjusted to the rear window, you will probably need to adjust the stops on the door glass to get the door windows to fit closely against the underside of the now-adjusted folding top rail.  It is a tedious, iterative job, in my experience.


If the door fits the body opening well, we are not looking at body sag.  If you can't get a good gap at the bottom of the door and the rear of the door at the same time, okay, maybe we have a body sag issue.  But even then, we can tweak things with tightening body bolts and using shims or thicker rubber body pads to twist the body back into a shape having a properly shaped door opening.
Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

Jay Friedman

Richard, I would follow Art's advice as he (with me holding the tools) just completed a lengthy major adjustment of all four windows in relation to the top on a '49 convertible. 

By "well" he means the area behind the rear window where the top struts are mounted to the body.  There are several adjustments that can be done to line up the rear windows correctly, both side-to-side and front-to-back, as well as the position of the top frame.  If I remember, you must remove the side trim panel to access that area. 
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

Brad Ipsen CLC #737

Question to Art.  I have not done a 49 convertible but in 1940 there is not supposed to be any rubber in the body mounts on a convertible, only an anti-squeak pad and hard shims.  In sedans extra light lock washers are used and only minimal torque on the bolts.  Convertibles are standard lock washer and much tighter bolts.  I would have thought that this general scheme would have been used up to at least 49 because the frame is essentially the same.
Brad Ipsen
1940 Cadillac 60S
1938 Cadillac 9039
1940 Cadillac 6267
1940 LaSalle 5227
1949 Cadillac 6237X
1940 Cadillac 60S Limo

Jay Friedman

 
Quote from: Art Gardner CLC 23021 on September 04, 2019, 05:49:48 PM
If the door fits the body opening well, we are not looking at body sag.  If you can't get a good gap at the bottom of the door and the rear of the door at the same time, okay, maybe we have a body sag issue.

Brad,

Richard still has not replied as to whether the doors fit well or not, as per Art's query.  So it could be a window/top frame adjustment problem and not body sag.

As for your point about rubber in the body mounts, it is my understanding that there are no rubber pads in '49 convertible body mounts, similar to '40.
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

Caddy Wizard

An old body man's trick to fitting the doors to a door opening is to "jack up" part of the body relative to the frame where needed.  Essentially, one is twisting the body front to back or back to front to match the shape of the door opening to the shape of the door.  This is most useful on hardtop coupes and convertibles and seldom is even needed (or appropriate) on sedans with B-pillars.

The concepts works the same whether the car has rubber body mounts or just metal shims.  One just puts in a thicker or thinner element as needed, be it a shim or rubber pad.
Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

Caddy Wizard

Did we ever figure out if this was truly body sag?
Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)