roof rot malibu

[malibujustin]

Justin, I would add a few temporary braces in. It can't hurt, and it's always better to be safe than sorry.

You'll probably need to use a combination of most of those tools you listed to get the old roof cut off. I would use the ones that create the least amount of heat and distortion, to avoid creating more work for you down the road.

The only one you listed I'm not a fan of is the torch, unless you're just using it to make very rough crude cuts well away from the final cut line. Try to use the ones that you will have the best control over, and precision with.

Also, if I might add, try and place your cuts on all the pillars, both pieces new and on the car, staggered from each other. Even on the same pillar of possible. This will ensure more strength, and less possibility of having the whole roof come off in the same plane in the event of a bad collision.

Just something to consider before you start. Hope this helps.

Donovan

Thanks mr Donovan. David by the way. Lol. Justin is my son. Father son project. His first car. Won't go the torch route. Can you explain staggered cuts? Thanks

 

[Clutch]

To add to Clutch's post, if some of the A-pillars are salvageable, slice them in half vertically, and make a 'Z' weld rather than a butt weld. Stronger and safer. Don't forget to treat the inside of any place you have accessible - raw metal, welds especially, are starter spots for future rust.

Try to find a reference point common to both roofs around the windshield that you can use as a measurement reference.

And use weld threw primer. Also prep work is everything dry fit the roof and make shore it's right take measurements of the window openings be for you make any cuts and write them down draw a picture so you have a reference if you don't have welding blankets pull the interior keep the dashboard covered be careful but don't be scared it's only mettle and plastic it's just a car don't let it scare you if you have a question just ask

 

[malibujustin]

Ok the questions you ask can have very technical answers in collision work there are procedures for splices the general rules witch do very are inner and outer panels should not be but welded in the same spot. So I would cut the inner structure long on the car and short on the Donner so the replacement roof skin gos over the original inner structure by 4 to 6 inches this will require drilling out some spot welds and staggering your cuts then plug welding the drill holes when re installing the new roof you shouldn't just lop it off and but weld it on I hope this helps my battery is dying so I hope another body man chimes

Mr clutch...I will be getting rid of the whole roof. The inner structure of mine is very rusty. Replacement structure is in great shape. My a pillars are crap about 4 inches down. Replacement has about 8 inches of good a pillar.

 

[malibujustin]

Was going to cut a pillars only as much as needed to get past the rust. Then treat. After that weld me some metal to the inside of the existing a pillar then slide replacement roof/a pillars down over that to add some extra material to weld to in that area. Cut out spot welds on existing b pillar and just weld to replacement in same area. C pillars was hoping I have enough to use factory seam and melt out lead and remove spot welds and weld into place. Don't know if I have enough c pillar on replacement to do that part. Of course I will measure and measure again and again

 

[malibujustin]

Thanks guys for all the tips and advice. I certainly will use all of them and really study on it before I make any cuts...and refer back to the tips and advice

 

[Clutch]

Mr clutch...I will be getting rid of the whole roof. The inner structure of mine is very rusty. Replacement structure is in great shape. My a pillars are crap about 4 inches down. Replacement has about 8 inches of good a pillar.

Ok that's fine but you need to stagger the seams I wish I had a picture! My phone is dead and I hate this kindle I can barely use it hopefully someone will chime in with an I-car like answer I try to only read with this thing My fingers are to big for try the I-car web site

 

[ssn696]

Z-cut example: Short-bed Chevy pickups are few and far-between. Long beds are much more common. With careful measurement and layout, you can shorten the long chassis by making a lengthwise cut in each frame rail about the centerline. Then make a vertical cut from the top at one end and another vertical cut from the bottom at other end. Pull the frame halves apart, and you have stair-steps. Take an equal amount off each half of the frame rails and push them back together. With a little fine trimming, equally on both rails, weld the two halves of each side together. Now you have a short bed frame without a weak spot in the middle because the joint is spread across the length of each rail.

 

[Rktpwrd]

Thanks mr Donovan. David by the way. Lol. Justin is my son. Father son project. His first car. Won't go the torch route. Can you explain staggered cuts? Thanks

David. Sorry, my apologies.

I scoured the 'net for hours searching for a good pic of what I mean. There's not much out there for pics unfortunately, but this one is about as close as I could find:

It's very similar to what you mentioned, you want to have your cuts offset from each other on the same pillar, and have overlap to plug weld into if possible.
In the photo above, they were able to do it at a factory overlap point. You might get lucky and be able to do that too on your "A" pillars if the ones on your Malibu are anything like the ones on my Cutlass:

The "B" and "C" pillars may be a different story tho, as there's no obvious overlap joint to separate them at:

Again, I know it's on my Cutlass, and not on a Malibu, but the same principle still applies. Don't cut all the way through in a straight line. Stagger the cuts whenever possible. This adds strength and maintains the structure.
I would invest in a high quality spot weld cutter, and try to separate the pieces where the factory assembled them.

The first photo above was borrowed from NastyZ28.com, where they replaced a roof on a Camaro. It may be of some assistance.

http://nastyz28.com/threads/roof-replacement-fisher-t-tops.213257/

Hope this helps a bit. Good luck!

 

[malibujustin]

Z-cut example: Short-bed Chevy pickups are few and far-between. Long beds are much more common. With careful measurement and layout, you can shorten the long chassis by making a lengthwise cut in each frame rail about the centerline. Then make a vertical cut from the top at one end and another vertical cut from the bottom at other end. Pull the frame halves apart, and you have stair-steps. Take an equal amount off each half of the frame rails and push them back together. With a little fine trimming, equally on both rails, weld the two halves of each side together. Now you have a short bed frame without a weak spot in the middle because the joint is spread across the length of each rail.

That makes alot of sense. Thanks for the tip.

 

[malibujustin]

David. Sorry, my apologies.

I scoured the 'net for hours searching for a good pic of what I mean. There's not much out there for pics unfortunately, but this one is about as close as I could find:

View attachment 68890

It's very similar to what you mentioned, you want to have your cuts offset from each other on the same pillar, and have overlap to plug weld into if possible.
In the photo above, they were able to do it at a factory overlap point. You might get lucky and be able to do that too on your "A" pillars if the ones on your Malibu are anything like the ones on my Cutlass:

View attachment 68891

The "B" and "C" pillars may be a different story tho, as there's no obvious overlap joint to separate them at:

View attachment 68892

Again, I know it's on my Cutlass, and not on a Malibu, but the same principle still applies. Don't cut all the way through in a straight line. Stagger the cuts whenever possible. This adds strength and maintains the structure.
I would invest in a high quality spot weld cutter, and try to separate the pieces where the factory assembled them.

The first photo above was borrowed from NastyZ28.com, where they replaced a roof on a Camaro. It may be of some assistance.

http://nastyz28.com/threads/roof-replacement-fisher-t-tops.213257/

Hope this helps a bit. Good luck!

Thanks for the pics and link. That is kinda how I want to do the a pillar. I think the b pillar attaches to roof braces with spot welds mostly so I will be using my spot weld cutter alot. The c pillars are one of my concerns. On my 66 malibu at the top of quarter panel up on sail panel it overlapped the roof panel with spot welds and was filled with lead. Melted the lead out and cut out spot welds to replace quarter. So on that one and most cars, not sure about newer cars, there is a factory overlap. I guess in 80 they still done that?? Don't think I have enough c pillar on replacement to do that with. May just "peel" off skin at rear where it runs over into back window upper channel and plug weld that part back in. Thoughts?? I do really appreciate all the tips. Thanks guys