1 piece floor pan installation questions - 70 Cuda auto

[rb70]

Does the dash need to come out for the floor pan to go in?

What do I use to seal the seams?

What is a good way to break the welds - grind or hammer and chisel?

I am doing floor pan, rear wells and rear seat pan, so any help would be very much appreciated.

[Topcat]

Alot of products out there for the sealant.

I used 3M 08500. It stays pliable without cracking. Not the original color like OEM had which was a honey color. The factory painted over the seams originally. Also where the trunk floor pans met in the back.

Between the front floors and the rears, a tar was used down the center seam.

[ksierens]

I used a brushable seam sealer like they used from the factory.

[72cudamaan]

Spotweld cutters and grinder are your best bet.  You don't wanna tear the base metal with a chisel.  I would suggest that you replace one section at a time. Remove the front and rear floorpans, but keep the rear seat pan in place. Install the front pan. Then remove the seat pan and replace. Finally install the rear floor pans. This worked well for me in keeping everything aligned properly.  Of course, just a pennies worth of advice from a novice.

[buddydog]

From one that has spent the last two weeks busting spot welds, find them, mark them, center punch them, drill them out with a 3/8" bit (gently of course so as not to punch through the second layer) and then, if need be, gingerly apply the smallest amount of force possible with the chisel to separate the panels. You may need to hammer and dolly the mating surfaces flat once you've ground off any remaining weld "residue".

As far as order of removal, take the panels out in order of what is on top first, then reverse for installation.


G

[Topcat]

I used a brushable seam sealer like they used from the factory.

I tried the 3M brushable seam sealer in the trunk and it started getting cracks. So I switched.

[rb70]

Still need to know if the dash has to come off?

Thanks for the answers guys!!

[67vertman]

Still need to know if the dash has to come off?

Thanks for the answers guys!!

Not that I am awear of.  How far up does the rust go? 

Most of the pans, only go up to the bottom of the dash.

[rb70]

Thanks 67, rust soes not go past the seam. So I can leave the dash in(for now).

[Challenger III]

I am in the process of doing the same thing. Spot weld cutters work great. I drill into the center of the weld a little bit with a tiny drill bit to keep the cutter centered. I then cut with the cutter, then use a heavy duty gasket scraper to separate the two pieces. Then grind as necessary. i took the dash out to save injury to my head while working! 
There are lots of pictures of dealing with spot welds in our restoration thread section. Good luck! 

['Cuda Hunter]

Try a spot weld drill bit.  With the little nipple on the end.
Those work great for me.  Doesn't damage the metal underneath. 

http://cgi.ebay.com/Spot-Weld-Cutter-Drill-Bit-set-HSS-1-4-5-16-3-8-USA-/380296559770?pt=LH_DefaultDomain_0&hash=item588b70fc9a

[CudaNut]

We use the cobalt ones made by Keysco, they have a little pilot on the end and are lifetime guaranteed. If they are too pricey the ones made by KnKut work well and are a little shorter for use in tight areas...The "plug" style ones Harbor Freight sells also work ok if you need to cut a round hole in the top panel to plug weld, the blair cutters will even fit on the arbors and will last longer.
The last link is of a Steck super panel buster that hooks to your air chisel. It makes separating the panels much easier, just be sure to reinforce it where it the blade joins at the chisel or it will eventually crack and break. I've had to fix several that way...
http://www.sears.com/shc/s/p_10153_12605_SP100A1798S1705095403P
http://www.tooltopia.com/knkut-kk3-100sw.aspx
http://www.tooltopia.com/steck-autobody-20017.aspx

[pywell]

A tip for keeping clean and great looking seam seals.

Put masking tape on each side of the seam all the way down about the same distance apart from the seam. Purchase a tube self leveling seam sealer, fusor makes a great factory replacement seam sealer and apply a bead of it all the way down the seam, be generous. Then use a water spritzer (we use 900 by RM products which is a wax degreaser) and spritz the freshly applied sealer. Using a plastic/surgeon glove we then lightly run our finger down the sealer so it is evenly spread out across the taped area and seam. Once done you tear the tape back at 45 degrees away. This will leave a even bead of sealer that looks even, smooth and about 100x nicer then brushed on sealer.