Muscletang needs new floor pans - advice?

[Carolina_Mountain_Mustangs]

I have seen some youtube videos showing them in early mustangs but he did not use a jig and had big issues with other panels. A friend has a shop and he tells me it is much easier to put the full in than the patches but he has a jig. As I have stated before you need a jig or fixture to locate the frame to the floor. You need to make sure that the body is sitting correctly before fitting and welding. The dimensions are given in the Ford car shop manual for the body. I have attached a scan of the 1973 manual showing dimensions. A frame shop might have a book with more detailed dimensions. I know when I replace the front inner fenders and radiator support on our 84 mustang the frame shop gave me all the dimensions to check before welding them in. If you just put the pan in and weld it nothing is going to fit or work right after and nothing can be done to correct it but take it back out. At the factory the locator holes in all the panels align them in the weld fixture if you do not do the same it will be bad.

David

1973_Mustang_Cougar_Underbody_Dim.img.pdf

 

[tony-muscle]

I have seen some youtube videos showing them in early mustangs but he did not use a jig and had big issues with other panels. A friend has a shop and he tells me it is much easier to put the full in than the patches but he has a jig. As I have stated before you need a jig or fixture to locate the frame to the floor. You need to make sure that the body is sitting correctly before fitting and welding. The dimensions are given in the Ford car shop manual for the body. I have attached a scan of the 1973 manual showing dimensions. A frame shop might have a book with more detailed dimensions. I know when I replace the front inner fenders and radiator support on our 84 mustang the frame shop gave me all the dimensions to check before welding them in. If you just put the pan in and weld it nothing is going to fit or work right after and nothing can be done to correct it but take it back out. At the factory the locator holes in all the panels align them in the weld fixture if you do not do the same it will be bad.

David

I am doing my floors one side at a time so to reduce distortion as much as possible. I did check the squareness and all was good. I will assume that if you do the whole floor you certainly need some kind of fixture.

 

[83slimer]

I have seen some youtube videos showing them in early mustangs but he did not use a jig and had big issues with other panels. A friend has a shop and he tells me it is much easier to put the full in than the patches but he has a jig. As I have stated before you need a jig or fixture to locate the frame to the floor. You need to make sure that the body is sitting correctly before fitting and welding. The dimensions are given in the Ford car shop manual for the body. I have attached a scan of the 1973 manual showing dimensions. A frame shop might have a book with more detailed dimensions. I know when I replace the front inner fenders and radiator support on our 84 mustang the frame shop gave me all the dimensions to check before welding them in. If you just put the pan in and weld it nothing is going to fit or work right after and nothing can be done to correct it but take it back out. At the factory the locator holes in all the panels align them in the weld fixture if you do not do the same it will be bad.

David

I ve seen other places mention if you level the car with a laser level and properly support the front end that the full floor wont be an issue. I might even tack a square stock across the front of the car between the rockers to each frame rail to hold them in place while i cut the old floor out.

 

[73mach1UK]

:dodgy:go ahead with the floors, just make sure the inner and outer rockers are fine . if those are rotten you need to them first and they are tricky. Mach 5

does anyone do replacement inner rockers?

Rich UK

 

[73mach1UK]

I need my floors replaced but i'm not smart enough to do it and no one in the Tulsa area is interested in tacking the task

Floor pans are pretty easy. I could probably do a set in a good weekend. Bring it up to PA!

But seriously a lot of people have done them on here with limited skills and had good results. Just get proper tools and take your time.

I have looked on youtube with no luck, will keep looking

Mexican, look at this guys videos, https://www.youtube.com/user/fuzzenut/videos?flow=grid&view=0&sort=da

start at video 51



I've learnt a lot from this guy and I haven't started my restoration yet!

 

[tony-muscle]

I have not been able to do much since my last update. Crazy with summer activities and travel for work, plus the garage has been quite hot at night. However, I manage to weld the driver's subframe connectors. They look very decent.

I have a question for the experts of the forum. I am doing my floors one side at a time. I am done with the driver's side except for priming/painting. I am getting ready to start on the passenger side, which I expect to go much faster due to the skills learn on the driver's side. In any case, my question is, should I prime/paint the driver's side before I continue to the passenger's side or can I leave it unpainted until I am completely done. I prefer the later option, but I don't know if I have to worry about my welds corroding. I anticipate they will be exposed for about 2-3 months before I am ready to completely prime and paint. As an alternative I wonder if I could use an etch and protectant on the exposed welds. I have the Eastwood After Blast 11971ZP cleaner, so I wonder if this protection would be enough for couple months. Thoughts?

Thank you.

 

[Jeff73Mach1]

You can get a rust prevention spray from Evaporust that should hold you over and will wash off with water before you paint.

Cheap and available at many auto part stores. Just get it cleaned off before you paint.

 

[tony-muscle]

You can get a rust prevention spray from Evaporust that should hold you over and will wash off with water before you paint.

Cheap and available at many auto part stores. Just get it cleaned off before you paint.

Great idea. Just purchased.... as always, thank you so much for all your help!


Just wanted to post a picture of the rear of the passenger's floor pan in my car. WTF??? Is this even called a repair.

Just started on that side. Removed the seat platform, cleaned up and prep to start cutting. I will have the two seat platforms sandblasted and then I will redo the rusted sheetmetal? I will make sure I take measurements and make a template before sandblasting because I assume a lot will be gone in the process.

 

[tony-muscle]

Some time ago in this thread I posted pictures showing that the top of the passenger's side rocker panel has been cut. Here is another picture. Now I am working on this side taking out the floor and see that the rocker panel is slightly curved on the inner side. That tells me that something happened to the car on that side. That said, should I weld something at the top of the rocker. Maybe a few strips at the top between each edge. Any ideas?

 

[cudak888]

Doesn't look as if the rocker exterior was damaged. Looks more as if something very heavy dented the inner wall of the rocker after it was cut (it wouldn't have bent so easily otherwise).

Beat it back into shape from the inside with a mallet, weld up the gap with a piece cut off a donor rocker, and seal it up with epoxy primer followed with color coat (have it done properly with 2-pack, not a spray. Even if you can't see it, this area can easily get water trapped in it and rust out under the trim.

I can't explain why the rocker was cut though. Someone pulling a French Connection, perhaps?

-Kurt

 

[tony-muscle]

Doesn't look as if the rocker exterior was damaged. Looks more as if something very heavy dented the inner wall of the rocker after it was cut (it wouldn't have bent so easily otherwise).

Beat it back into shape from the inside with a mallet, weld up the gap with a piece cut off a donor rocker, and seal it up with epoxy primer followed with color coat (have it done properly with 2-pack, not a spray. Even if you can't see it, this area can easily get water trapped in it and rust out under the trim.

I can't explain why the rocker was cut though. Someone pulling a French Connection, perhaps?

-Kurt

Can I take a piece of sheetmetal, bend it to shape and weld it in place instead of using a donor? If so, should I use galvanized steel or regular?

1971 M-code Mach 1

 

[turtle5353]

You can make your own piece, but I wouldn't recommend using galvanized. When you weld galvanized metal the smoke it puts off can make you pretty sick. I have welded it many times before but you have to grind your weld area clean of the galvanized stuff before welding. I would stick with bare reg steel and prime and seal properly.

 

[Hemikiller]

Doesn't look as if the rocker exterior was damaged. Looks more as if something very heavy dented the inner wall of the rocker after it was cut (it wouldn't have bent so easily otherwise).

Beat it back into shape from the inside with a mallet, weld up the gap with a piece cut off a donor rocker, and seal it up with epoxy primer followed with color coat (have it done properly with 2-pack, not a spray. Even if you can't see it, this area can easily get water trapped in it and rust out under the trim.

I can't explain why the rocker was cut though. Someone pulling a French Connection, perhaps?

-Kurt

Can I take a piece of sheetmetal, bend it to shape and weld it in place instead of using a donor? If so, should I use galvanized steel or regular?

1971 M-code Mach 1

Yes, you can do that. Don't use galvanized steel, just use plain. Welding through galvanizing is both hazardous to your health and a PITA.

 

[tony-muscle]

Thank you.... another project added to the list

1971 M-code Mach 1

You can make your own piece, but I wouldn't recommend using galvanized. When you weld galvanized metal the smoke it puts off can make you pretty sick. I have welded it many times before but you have to grind your weld area clean of the galvanized stuff before welding. I would stick with bare reg steel and prime and seal properly.

Is the rocker gauge 18, 19 or what?

1971 M-code Mach 1

 

[Carolina_Mountain_Mustangs]

A little tip on the zinc coating putting off smoke. I worked around zinc die casting for over 20 years and as you would expect you breath the smoke from the casting machines and melt tanks. About 7% of the zinc is lost to smoke when it is melted. You will get a headache and feel a little sick if you breath too much. The cure is to drink milk. Our nurse at the plant would actually keep milk in her office for that reason. Too much of anything is bad for you but a little smoke has not been shown to be that dangerous.

Most of the metal in cars today is zinc coated either by hot dip or electro galvanized process. When the robots weld the panels the controls on spot welders do a pulse to melt the zinc and squeeze it out of the joint then it shoots the weld current to make a good spot weld. Most of us do our repairs with MIG or TIG and yes the zinc will bubble and weld will not be pretty. When they MIG weld the panels in the factory they do not remove the zinc and they hold. BMW still does manual MIG welds on some of the underbody. We made Fords front floor pan assemblies for the Econoline for many years and we MIG welded the wire forms for the dog house latch to the floor with Flux Core wire per their spec. The floor was hot dipped galvanized. I wish they had used zinc more back when they built the cars for less rust for sure. I would not worry about adding zinc coated metal for a little patch when everything else is raw steel.

I actually have to take zinc tablets to help prevent muscle cramps by Dr. advice.

David

 

[tony-muscle]

On the passenger side I have some rust above the area the replacement pan covers (see picture: yellow line represents the edge of the replacement floor pan and the blue circled areas represent some through-rust). I wonder if any of you have some left over floor pan that has the depression or channel rib circled in the second picture so I can use it as an extension. If I can find some sheetmetal with this channel depression, it will make it easier to fix the area above the replacement floor pan. I don't have the capability of bending the sheetmetal to match this depression.

Also, you can see that there is some surface rust on the torque box that's attached to the floor pan. This rust is superficial and easy to clean. However, should I worry about more surface rust further up the firewall? Does this imply that I should cut more of the firewall/floorpan above the torque box to investigate?

 

[tony-muscle]

Continuing the last post i have been looking at panels for other cars that have the channel rib so i can use a section, but I am still hoping that someone in this forum has part of the firewall section leftover from their floor pan or firewall.

1971 M-code Mach 1

 

[turtle5353]

what about the old floor panel you cut out??

 

[tony-muscle]

what about the old floor panel you cut out??

That's option D at this time since there is rust on those areas. Not terrible, and it could be fixed, but I think I could do better.

However, I think I have a solution. I started looking at other repop panels for our cars and came through the trunk drop off piece. This piece is cheap and will give me a few inches of ribbing that would be enough to fix the firewall. The ribs on this panel are of the same dimensions as the ribs of the firewall.

http://www.cjponyparts.com/trunk-drop-off-driver-side-1971-1973/p/M409L/

 

[Qcode351mach]

Take a look at my vid around the 1:56 mark for the soultion to your problem


I don't remember if I used the 67-68 upper pan section or the 69-70 But one of those works u just need to modify a little for fit no big deal