One thing I've seen in common in many first gens is stress cracks along the rear quarter windows. After stripping some filler out of my drivers side rear 1/4 I've found a decent sized crack. I realize that this is due to the metal fatiguing with age. Is there any hope for being able to reinforce and weld the crack rather than replacing the quarter? If I am to replace the panel, could I get by with an 80% or would I have to do the full 1/4? Below you'll find pics.
Thanks for your help!

http://i5.photobucket.com/albums/y169/RhinoSS/68%20Camaro/Picture174.jpg
http://i5.photobucket.com/albums/y169/RhinoSS/68%20Camaro/Picture171.jpg

i got a 80 percent quarter in my garage. it doesnt look like it goes all the way up there.maybe half way at most.i never seen a camaro cracked there. maybe someone welded the rear quarter to the sail panel.the part behind the rear windsheild.i seen them split at front pillar posts tho.

Two of my dad's previous '68's had this problem as well as a few others I've looked at. Maybe it's just common in the car's I've looked at :confused:
Reading the description of the 80% on ricks' I've found the following.
Contains turndown for rear window fuzzy, extends into trunk jamb area, rear curves in like original panel for easy mounting of tailpan
To me, if it contained the turndown for the window fuzz, it should extend straight back from there. Am I incorrect in that?
Bill, are you sure yours is a true 80% panel and not a quarter skin?

The stress, or "torque" cracks are very common on the first gens. If you watch the movement of the quarter when you shut the door, you'll know why. The front of the quarter actually flexes a bit as the door is shut,since there is no roof pillar to support it up front in the jam area. The crack develops from opening and closing the doors over time and normal body flex of a unibody car,with that area of the quarter acting sort of like a primitive steel hinge. One way to prevent it is to weld an extra layer steel behind the quarter in the stress prone area. This prevents some of the flexing, resulting in less chance of cracking.

My car is cracked there on the driver's side. I've seen many with this same crack, nearly always on the driver's side. It needs to be welded before paint prep. If it's been leaded, all that has to come out and a decent patch made. I've also seen other GM models of the same era cracked or tweaked right there. More horsepower seems to predict the problem, but mine is only a 400 pontiac with the TH400 automatic. One would expect more problems with an aggressive clutch and four speed. Wide tires also lend to the failure. Weld it up or it will be back. You can't JB weld over that.

One way to prevent it is to weld an extra layer steel behind the quarter in the stress prone area. This prevents some of the flexing, resulting in less chance of cracking.

Bob, that's exactly what I've thought about doing. After removing my quarter windows, it looks like I should be able to weld a panel on the backside, without having to remove the quarter. I'd be interested to hear people's reactions regarding welding the crack up, vs replacing the panel.
I had always wondered why the cracks always appeared on the drivers side much more frequently than the passengers. The door flex makes a lot of sense.

Bob, that's exactly what I've thought about doing. After removing my quarter windows, it looks like I should be able to weld a panel on the backside, without having to remove the quarter. I'd be interested to hear people's reactions regarding welding the crack up, vs replacing the panel.
I had always wondered why the cracks always appeared on the drivers side much more frequently than the passengers. The door flex makes a lot of sense.

Yeah, my 69 driver's side did the same thing, and I thought long and hard, opened and shut the door,watched closely,and a very dim lightbulb went off above my head :) Yep, its flex, pure and simple. That front of the quarter can move a good 1/8 inch in my estimation.

Weld it on the outside, grind smooth, then weld in the plate from behind. Problem solved,and it will not return. In fact, weld a plate behind the pass side while you're at it. Good preventative measure.

Weld it up or it will be back. You can't JB weld over that.

When I purchased the car it looked like it had a healthy coat of bondo there. When I got to digging I found that it had been fiberglassed over prior to a repaint. It looks like it's gotten progressively worse since then.

Thanks for everybody's input. It looks like I'm going to be breaking out the welder. Bob, I sure will be adding a patch to the passenger side as well. I don't want to get this thing in paint and have it happen to the other side too :thumbsup:

Your photo sort of looks like there's some lead on the panel. That's why I mentioned it. The lead needs to be cleaned out before welding if there is lead there. Back the rear of the panel with a piece of copper sheet and weld it up. The weld won't stick to the copper, but you'll be able to get penetration to the back side. Practice on scrap before you weld on the car. No mistakes, means no regrets. You want to be tuned up for this repair.

Bob's theory about the driver's door closing is interesting. As I think about the failure, those other GM cars I see with the problem were all two door models with the longer doors.

Here's mine after a bit of light sand blasting.

http://i11.tinypic.com/4u2eio6.jpg

i got a pp-37L from ricks it is for a 67 camaro 80 percent quarter.like i said not 100 percent sure it goes all the way where you want it.

mine has the same cracks (both sides) i thought it was because the PO took a bat to the windows, and missed a few times.

Your photo sort of looks like there's some lead on the panel. That's why I mentioned it.

The Picture is misleading, but I completely see where you're coming from. In person, it looks like it's been brazed at one point in time. I do plan on doing quite a bit of cleanup before I repair the area. Also, thanks for the tips on the repair. I have a few old fenders that I'll be trying this on first.

There is already a brace in that area that is attached to the quarter in the window area and the box section running up from the outer wheelhouse. It's not much structure but it probably helps some. Would be interesting to see if the spotwelds were loose or the brace was broken on cars with cracks.

I'll look at this tonight when I get home and post my results. From my recollection, I believe all the bracing was still intact.