Tailgate area roof rust issue

[PBGBodyFan]

I acquired a wagon rear spoiler to put on mine, got it painted and as I removed the non spoiler hinges and pulled back the weatherstripping was met with a surprise, some good rust action and pitting right behind the weatherstripping between each hinge location. From the hinges outward there is zero rust. When pulling the weatherstripping off it was taking some rust with it. Scraped some off then took a wire wheel and grinding wheel with an angle grinder, then even cut some of the thin top layer of the pinch weld in spots. Sprayed por-15 metal ready then brushed por-15 on it once dried. Whenever the wagon gets a proper paint job the shop could look into cutting/replacing that section possibly but the car is typically garage kept and this should neutralize the rust pretty good.

I was surprised to see rust this heavy being a CA wagon that has no other rust and when removing the spoiler off a MN wagon I don't recall this area having any rust. Has anyone else found rust in this location on their wagon or another?

Pics of the loose rust, then after grinding/cutting.

 

[blk7gxn]

I have not seen any on my wagons at all. However It brings up a great point though. Not G body related, but GM related...I remember back in the 80's when individuals were purchasing Chevy celebrities, and the trunk decks would rust from the inside out, and it was hit and miss, some would some wouldn't. Buick Centuries had issues too on their deck lids etc... To me, its logically impurities in inferior steel they were using, different batches, hece the hit and miss and different areas of issues too. I'm glad you noticed this before it got worse and are taking appropriate measures!

 

[blk7gxn]

I acquired a wagon rear spoiler to put on mine, got it painted and as I removed the non spoiler hinges and pulled back the weatherstripping was met with a surprise, some good rust action and pitting right behind the weatherstripping between each hinge location. From the hinges outward there is zero rust. When pulling the weatherstripping off it was taking some rust with it. Scraped some off then took a wire wheel and grinding wheel with an angle grinder, then even cut some of the thin top layer of the pinch weld in spots. Sprayed por-15 metal ready then brushed por-15 on it once dried. Whenever the wagon gets a proper paint job the shop could look into cutting/replacing that section possibly but the car is typically garage kept and this should neutralize the rust pretty good.

I was surprised to see rust this heavy being a CA wagon that has no other rust and when removing the spoiler off a MN wagon I don't recall this area having any rust. Has anyone else found rust in this location on their wagon or another?

Pics of the loose rust, then after grinding/cutting.

By the way, great looking fleet of cars you have!!

 

[Ribbedroof]

Yes, my beige Pontiac had some there as well. I think on cars that sit out, especially when owned by people that like to park under trees, they accumulate dirt and other organic matter that gets washed into that area when the car gets wet. Poor design on the pinchweld for sure.

You should see all the crap that comes out of late model cars when you pill a fender off...it's a miracle to me that we don't see loads of them with rotten fender bottoms. Better corrosion protection, I guess. I have many times seen over 10" of debris in between the fender and pillar, hidden by the liner.

 

[Longroof79]

Mine had surface rust in that area, but along the channels there were a few rust holes that I later welded up. The hatch weatherstrip was notorious for trapping all kinds of dirt, leaves and assorted debris. Over the years I would pull the weatherstrip away in order to clean out all the composted crap that settled behind there, which is also the major cause of the hinge bases to rust away.