does anyone know what issue of mustang monthly that the article about instlling a one piece floorpans was in. if any one has done this any advice would be apreciated. placement of the jackstands is my bigest concern. thank you

 

Its best to do it with the heavy parts like the engine and transmission removed. The weight can cause the car to bend with the floor removed. I even pulled the front suspension and the entire interior, you could leave the dash and door panels, but the kick panels, and all seats gotta go. The fuel line and brake line for the rear brakes run down the trans hump, be sure not to cut them. Also dont cut the parking brake cable, you can unhook it relatively easily and move it out of the way.

When cutting the floor out, be sure to leave the factory flanges on the lower part of the firewall and in the rear. I used an air chisel with a body ripper, and separated the seams with a wedge blade. I cut it out in sections instead of one piece. Also I put mine in through the windshield, but you might be able to fit it through the door with the 1/4 windows rolled down. Whatever way you do it, getting it past the dash will be the tough part if you dont pull it.

Its a two person job getting a full pan in the car, I did it myself and fought with it trying to get it in right, two people makes it infinitely easier. If your car isnt severely rusted like mine was, and could get by with just full sides or partial patches, they are much easier to install than a one piece floor. My guess is you need to tear the car down quite a bit to put a full floor in, mine already was and it was a pain in the rear.

Once its in you need to make sure its positioned correctly before you weld, and dont do it with one continous bead. If you dont stagger the welds and tack it all in while making adjustments, you will have a floor that doesnt fit right. I tacked the rear first since it was located by the rear torque boxes. I found the front needs to have pressure on it so I can weld the subframe rails from under the car. Once you have it all tacked in there with small spot welds a good distance apart, like 1-4 feet apart, then you can final weld it in. If you arent replicating the spot welds, just put down 1"-2" beads about 1 foot apart, then put some welds between those after the first set has cooled.

I actually got in the car to weld the floor down, it should rest on the flange at the front where it meets the firewall, and the hump, also on the subframe front and rear. I am 240+lbs so most people wouldnt have much trouble with it, I was a good source of pressure to make sure it was in there good and tight..lol.

Mine is a 71 with everything removed, the floorpans are the same size for all of them with minor differences, but the room available in earlier cars, especially 64-66s is much less than in the 71 fastbacks. I highly recomend doing partial pans or only full sides unless you want to disassemble the car as far as I have.

 

Hey Todd....I hear tell you have to have the windshield out in order to get the full floor pan in the car. Is that right? Makes sense......

 

it sure helps... I think I could have gotten it inside from the door on the 71, but the glass might still be in the way. Figure for a full pan you gotta tear most of the car apart. if it has that much rust that the trans humps are rusted, you will need to tear the car down to get it all anyway.

Not very descriptive pics, but its before and after. I dont often get to take them while I work, so its finished work or I havent started yet... Gives you an idea of how far it needs to be torn down. The mounting points for the dash held the floor up when I put it through the window opening, it would NEVER go with the dash in, not enough room for it to fit.


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AHA! So the dash has to be cut out, and of course the steering wheel and column need to be removed. Crap! That's a butt load of work.

 

i think you could probably fanagel it up inside from underneath if u went at an angle

 

Everything about that car is a buttload of work... but yeah, sections are better if you arent going ground up like some of us lunatics..

 

I don't remember the article but you could check their website - it's pretty easy to navigate. It looks like Thumpin already took care of you though.

 

Unless it's just a complete bucket case, I'd recommend partial replacements as Thumpin suggested.

I just replaced mine and both sides were pretty much eat up, however, the hump and driver side toe kicker was ok. As was suggested, just tach weld it in at first. You may run into issues with the front frame rails and the pan not wanting to sit on them properly to weld. If that's the case, don't hesitate to drill holes and through bolt them to the rails and suck the pan to the rail. ( this was also suggested in the tech write up of mustangmonthly ).

I left my bolts in place after I replaced them with stainelss and just welded around them. Undercoating and primer/coating on top of the pan will prevent any future rust.

Lastly, when undercoating, no matter what product you use, do not skip the prep process. The pans are shipped with a thin layer of rust preventer and the coating product will not adhere. Just get a good oil/grease remover and wipe everything down.

Once everything is out of your way and you start cutting, it's not a very hard project. Infact, if you've a plasma cutter, you're way ahead and can have the floors cut and welded back in no time.

From tear down, cut out, prep, weld, coat to final assembly, I had 10 days total. This was on average 4-5 hours a day, sometimes less.

Good luck.

 

A quick question, should the rust preventative oil be cleaned off prior to welding? What did you use?