Trunk floor 68-70 Charger

[bandit]

Has anyone ever attempted to replace a full trunk floor in a 68-70 Charger without having to remove panels? Is there any way to get it in? You can buy it in two halves but have heard the two sides rarely mate up well so would rather install the floor in one piece or trim the full piece and get it in somehow.

 

[RyanSchoen]

It won't fit unless you remove the rear valance or tail panel.

How bad is yours rusted? I have seen just the center cut out and replaced before.

 

[bandit]

Thanks. I figured it wouldn't fit in one piece without some major work.

The center is the main problem but there are a couple of dime sized rust holes that crept up onto to the left side too.

What do you think of sealing up the current rust with POR 15 then just overlaying the new pan(s) vs completely cutting out the old one first.

 

[benno440]

imo remove the cancer completely and seal it well for lifelong protection, you will sleep easier also

 

[5wndwcpe]

Throw up some pics and we can be a little more specific.

 

[bandit]

Here are a couple of pics. There are holes in it but the majority is hidden by the gas tank underneath so would like to just lay the new floor on top after sealing the existing one so I do not see extra welding seems from below. Plus this is my first time MIG welding so would like to keep it to a minimum.

Those black spots you see are the holes. I applied Miracle Paint(like POR15) to the underside a few months back and it came up a little through the holes.

 

[CTMopar]

I think you are asking for trouble if you leave the rusted one under the new one. That will be a moisture trap and the rust will grow. Practice welding until you are comfortable then do your repair.

 

[Propwash]

I would lay the fresh metal over the old alright...then trace an outline around it and cut out the rotten metal underneath..weld in the new. I put an AMD 2pc trunk pan in my '69 roadrunner and '68 Coronet and they fit great. If you're worried about a seam, buy a 1pc, cut it in half, install and butt-weld back together. With some grace you can make it nearly impossible to spot. The two piece is offset flanged in the middle, making it easier to spot, but allows more ease with installation and adjustment. Do yourself a favor and get that garbage out of there. Looks like you have rot running all the way out to your shackle mounts. It's a Uni-body and partially relies on the floors/pans for integral support and yours is looking pretty weak. As far as your welding skills, well a pan is a good place to start learning unlike a fender, quarter or other outlying panel that requires precision finishing. Watch some video's, read a book, practice on some scrap and ask lots of questions on forums like this...put in the effort and you'll be on your way.

 

[detmatt1]

Yep, you should completely remove it and treat the insides of those rear rails with some "Rust Bullet" while the pan is off.

 

[wannadrag]

Cut it out,in the long run you'll be happy you did.

 

[bandit]

I was afraid of that. Thanks everyone for your help!

 

[5wndwcpe]

Keep in mind as well, just because you can get a full size pan, doesn't mean you have to use the whole thing. Pictured is the car I'm doing right now. The center of the pan and an area just to the right of it was shot. What I've done here is remove the old metal directly over the frame rail so I won't have to finish the weld on the bottom and there's no chance of blow through, as with a butt weld down the middle of a 2 piece.

You can buy a one piece floor pan and split it in three with the seams directly over the frame rails. Is this more work ? absolutely. But, it saves you from removing a quarter (or tailpiece) and eliminates the need to finish the weld on two sides.

 

[bandit]

nice work. How are you cutting the old floor out and not damaging things when it is goes right over the support rail? Did you just use a cut off wheel and were just very careful when you went over the braces?

Also, why do you have holes in both top and bottom pieces to be welded? I am very new to Mig welding but thought only the top overlapping piece would have the hole and would be welded to the solid bottom piece by filling that top hole with the weld.

How are you guys cutting your metal sheets like this in general. Scissors can curl it and can be hard to keep super straight. Automatic shears(I have) will cut very nice but take out a 1/4' piece as it cuts. A cut off wheel seems logical but seems like a lot of cutting for this way. How do you guys do it. e.g. if you wanted to cut the new full trunk floor piece into three pieces... how would you do it for the cleanest lines and least amount of waste?

 

[5wndwcpe]

I use a 1/16" cutoff wheel for the easiest cut and removal of the least amount of metal if I need both sides of a piece. If one side is being discarded, then I use an air nibbler. If you take your time, following a scribed line is not difficult.

The small holes you see in the frame rail and floor pan are for self tapping screws. These hold the floor down as I weld. When your all done, you just back the screws out and weld up the holes. At worst, you just have to touch up these spots from underneath.

As far as cutting out the existing floor without damaging the rails, I hog out the middle of the floor with a sawzall right at the edge of the framerail to buy room to work. Then I measure in about 3/8" and zip the upper layer of sheetmetal only. Next up is an air chisle the peel back the remnants and dress up the rails with a small grinding wheel.

 

[Propwash]

Plasma Cutter majority of the time or I sometimes do the same....1/16" cutoff wheel or an air bodysaw

 

[bandit]

Thanks for the tips. I have been leaning towards getting the full pan and cutting it to use what i need. Similar to yours 5wndwcp, my middle pan and one side needs work. I could cut off the side I don't need on the new pan and probably fit the pan in without removing panels. I also do not want to screw with the gas tank braces underneath so will probably cut the new floor piece to go right up to where the existing tank braces are underneath. I am picturing doing an overlap of the seams since my wedding skills are still new and not sure about doing a butt weld. I imagine I will have to go underneath and weld too though since there is no brace in that area.

My original idea was to just cover the old pan with POR15 to encapsulate the rust then overlay the new pan on top putting seam filler or a similar caulk around all edges to ensure no air could get in between the two panels. I was then going to just weld the new pan to the old. From underneath the pan looks good (gas tank covers the existing holes) so thought it was an easy fix. Seemed like a good idea to save some work.....