Stress cracks ??

[WhiteTtype989]

Anyone else notice cracks or waves by the top of the pillars which separate the front doors from the rear windows ? i notice one side of the regal i bought has a little crack / wave just wondering how many of these cars show this ?? Is this a bad thing does thing mean the frame / body have been flexed ?

 

[87GNSteve]

90% of the TRs have them....its from terminal horsepower.
If a car has low miles and is driven easy it might not happen. I used to see that back in the day when the cars were 3-4 years old!

 

[83ttypecooled]

Hi,
A problem, definitely.I don't have cracks yet,but can see stress waves to the rear and below the quarter window on the passenger side. Would bushing replacement help this? I guess the damage is done, though.

 

[Daniel Jost]

mine had waves when i bought it, and now they are cracks, GM used bad filler there in the 80's, my brothers 88 Monte SS has them to... I just use them as a horse power guage I have all the body stiffeners too...

 

[83ttypecooled]

Hi,
That's not filler, it's steel.What do you think about bushing replacement arresting this problem?

 

[novaderrik]

Hi,
That's not filler, it's steel.What do you think about bushing replacement arresting this problem?

i've never looked at one closely, but i'd suspect that they crack right where the 1/4 panel meets the roof. and, yes, there is filler there from the factory.
the G body chassis and body is pretty lightweight for it's size compared to older cars- and as a consequence, isn't very stiff at all for a full frame car. that was GM's way of meeting mpg requirements and maintain something resembling performance with the wheezing powerplants of the late 70's- build the cars out of less metal, and the metal they did use was a thinner gauge. this is true for all the metal on the car.

 

[daviss]

You mean these? Please disregard the dirt. I had it sitting out at a friends house while I was building my house.

I don't think Buick designed these cars to handle the amount of torque we are throwing at them. I'm pretty sure a cage should remedy any additional damage.

 

[toofastforyou]

I've owned my GN since new back in '87 and raced it (and still do) with no cracks in the driver's door pillar. The secret in the GNX-style rear seat brace and installing all the body bushings that were missing from the factory. Also I have a 6pt. roll bar but I don't know to what extent that helps...
:wink:
Claude.

P.S: Some GN owners wait until it's too late and that there are already cracks that appear to install a brace...My advise is DO IT NOW before the problem occurs...if not, it'll crack one day and become a weak point next to impossible to fix permanently after...

 

[Gary Wells]

I've owned my GN since new back in '87 and raced it (and still do) with no cracks in the driver's door pillar. The secret in the GNX-style rear seat brace and installing all the body bushings that were missing from the factory. Also I have a 6pt. roll bar but I don't know to what extent that helps...
:wink:
Claude.

P.S: Some GN owners wait until it's too late and that there are already cracks that appear to install a brace...My advise is DO IT NOW before the problem occurs...if not, it'll crack one day and become a weak point next to impossible to fix permanently after...

I think that in your case, the 6 point roll bar might be the biggest assist in arresting the cracks, or preventing them alltogether. As far as whether the seat brace and all of the body bushings will prevent this, I am in the process of finding out the hard way. I have a 23K original mile mid-12 second car that has all of the body bushings and all of the braces, but no roll bar.

 

[87GNSteve]

When you start making real wheel standing power then you buckle the sheet metal over the rear wheel to the trunk lid edge. Thats on a fully caged cars too, you see those cars at the events all the time.
its always something......

 

[MSDGN]

When you start making real wheel standing power then you buckle the sheet metal over the rear wheel to the trunk lid edge. Thats on a fully caged cars too, you see those cars at the events all the time.
its always something......

That's due to notching the frame but not putting in any type of bracing...

 

[HP Man]

My Daughter's 86 T also has these stress cracks. Probably raced some and is missing the back braces, body bushings etc. Probably adding these braces and new bushings will help? My two 87 GNs didn't do it? Why? Don't know? Gene

 

["Turbo-T"]

I've always wondered if this is primarily for cars that are raced at the track on slicks and no stiffeners? Or can they crack if you punch the pedal on asphalt with street meats that can't keep from spinning?

 

[87GNSteve]

I've always wondered if this is primarily for cars that are raced at the track on slicks and no stiffeners? Or can they crack if you punch the pedal on asphalt with street meats that can't keep from spinning?

This used to happen back in the day to new cars; I think if you drove on pothole cratered streets it would do it too.

 

[Turbo Steve]

I installed the Kirban GNX back brace made by Tinman its much stiffer then the xx braces

 

[Gary Wells]

Fwiw, the stress cracks can and will occur given enough mileage and spirited street driving, even on a bone stock car with bone stock horsepower & torque. I owned a bone stock '87 10K mile turbobrick limited and used it as a daily driver until I sold it at about 96K miles or so. Did not modify anything, and somewhere along in that mileage it developed the fateful stress cracks on each side, but very small and only about 3/8" long or so. I had the Kirban rear seat braces, GNX body bushings, and the missing body bushings installed on my 23K mile car soon after purchasing it at 8K miles or so. HTH