Trunk Floor Repair or Replace

[70_440-6Cuda]

Hey all - quick question for the experts - I have some pin holes in my trunk floor, but no major rot.  Nothing bigger than say a pencil eraser.  Would you repair or replace the whole floor with an AMD replacement?  AMD has them in stock now, and my body man said easier to replace the whole floor but I am not convinced.  I will post some pics later today.

Anyone have a similar experience and what was the solution?

[anlauto]

I would take the advice of the person doing the repairs because he may not be confident in his own work to patch the areas required properly. In either case, you should buy a new floor so you can use it for patches if not installing the whole panel.

[70_440-6Cuda]

Thanks Alan, that was my thought as well, just thought I would get some feedback here as I am not a metal guy.  My guy is extremely talented with metal work; he just said it is more work than t is worth to braise a bunch of small holes and clean it all up etc...

[B5fourspeed]

How many pins holes are there?You can have someone hold a piece of copper from the underside against the pin hole and someone welding from the top.Weld will not stick to copper.It takes about 15 to 30 seconds to fill the hole.A little grinding and some mar glass,sanding and priming you would not have more than 3 to 4 hours of time.If the metal is thin and you have blowouts then I would go to plan B.

[70_440-6Cuda]

How many pins holes are there?You can have someone hold a piece of copper from the underside against the pin hole and someone welding from the top.Weld will not stick to copper.It takes about 15 to 30 seconds to fill the hole.A little grinding and some mar glass,sanding and priming you would not have more than 3 to 4 hours of time.If the metal is thin and you have blowouts then I would go to plan B.

Thanks, I am going to do some closer "inspection" this afternoon and see if there is a lot of thinning

[Brads70]

Pretty rare to have just a few pinholes? The panel has to be pretty thin? E-bodies are notorious for trunk leaks. If it was me I'd rather  new sheetmetal on the trunk floor. 

[larry4406]

Be mindful of 70 vs 71 trunk floors should you replace.

[torredcuda]

If there are pin holes the metal around those is probably pretty thin - I`d replace it rather than have a weak floor or more holes in a couple years.

[71GranCoupe]

Be mindful of 70 vs 71 trunk floors should you replace.

They used 70 floors on the early 71's. Not sure when the new design was implemented, so if an early 71 car, match it to the correct trunk pan by visual and not the year.

[anlauto]

I never repair any rusted area of a car before having it media blasted to get ALL the rust out....So many times you can fix one small area only to find rust right next to it later on..

[Filthy Filbert]

Replace the floor.

I've got a good amount of experience in metallurgy and trust me, you don't want to be trying to "3d print" filler sections by mig welding against copper backing. 
At best it's a visual repair only. 

[soundcontrol]

I started out with patching mine, then I went on to full sandblasting and discovered more thin areas, I could poke a hole easy with a screwdriver in some spots, so I replaced the whole floor.

[70_440-6Cuda]

Thanks all - decision made - new trunk floor ordered for my '70.  Great points from everyone, helped me make a final decision,  and I think save a bunch of time.

[Jocigar]

I think that you will always be told to replace it all, or to do it right and replace it.  There is a fine line on the decision making, replacement it great as long as you know the can of worms you are opening.  on the other hand there is nothing wrong with making a few patches or spot welding some pins holes if not very thin or swiss cheese.   

I think the inclination now days is anything but full replacement is half ass and sometimes it is but sometimes its overkill.   As I mentioned there is a fine line and 'doing it right' doesn't always incline you to replace.   

This is what to consider when replacing; To replace trunk floor you can remove rear cross member and slide it under tail panel.   To remove the old floor you will/he need to remove spot welds on the cross member, across tail panel, on the trunk floor extension, inside the wheel wells, on frame rails and across rear upper seat area.    While in there you might find you need new trunk extensions, new cross member extension, maybe new cross member, maybe find some rot at the wheel wells under the sealer.  You will also need gas tank braces or will need to remove old and recycle them by re-welding onto new floor.    Nothing wrong with doing all the above and you will feel good knowing everything else was addressed at the same time, just know what it can turn into parts and time wise in comparison to a few hours in patches or spot welds.          

[DeathProofCuda]

I think the inclination now days is anything but full replacement is half ass and sometimes it is but sometimes its overkill.   As I mentioned there is a fine line and 'doing it right' doesn't always incline you to replace.