Muscletang needs new floor pans - advice?

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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
Awesome... that's why I love this forum, I found the part:

http://www.cjponyparts.com/floor-to-firewall-extension-1965-1970/p/M126R/

For some reason I did not see it when I was looking for all their sheetmetal. I think it will fit like a charm.... Thanks a ton!

 
Well, after a long holidays break I am finally back working in the car. Today I think I won the first of many battles. I was able to get the driver's side seat riser out. The rear edge had the rear floor pan welded on top. I was able to take it out with little damage. The front edge is badly rusted, but the rear edge is not terrible. I decided to save this one so I will clean out all the surface rust and redo the front edge. In any case, I needed to rework a new one so I will try to save my current one.


BTW, a tool that was very useful was a seam buster. I got this one from Amazon, http://www.amazon.com/Lisle-51900-Spot-Weld-Chisel/dp/B000BQXBJK/ref=sr_1_3?ie=UTF8&qid=1420953243&sr=8-3&keywords=seam+buster

I highly recommend this tool since it makes the separation of spot welded panels a lot easier. I tried with a regular chisel for a while and it does the job, but it takes more work and you end of bending the seams a lot more that with the seam buster.
The tool I need, very good, i ll try to find this locally. Maybe I can save my seat platform in this way.

BTW you are doing a very good job, I follow your thread and try to do similar but body work is not my task.

Anyway, we learn every day :)

 
The passenger side floor is finally cut out. This had more rust than the driver's side. It also had a very bad previously done repair. Couple of the factory spot welds between the transmission member and the floor were terrible (last pic). These make my spot welds look great.

Now to start cleaning up, remove some rust, weld a bunch of holes, prime, prepare, etc....

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Does anyone have pictures of our torque boxes? I saw some repops, but none are for our 71-73 Mustangs. I am trying to understand what's behind the firewall area before I decide to cut more or less. I found some surface rust on the outside of the torque box, between the box and firewall pan, like if at some point water was in there. As far as I am concerned water shouldn't get in between the box and firewall pan from the top, right? If water gets in between the box and pan should be from underneath, right?

Do you guys spray anything inside the torque box or inside the space between the box and the firewall? I am thinking of spraying some Eastwood inside frame protection in the areas I can' access and epoxy prime the areas I can access. Will it be a good idea to top coat with a rubberized type of undercoating?

 
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Does anyone have pictures of our torque boxes?
Here's the original RH torque box out of a '73:

Passenger's footwell fits on top of this:

fz43cx.jpg


Front right - as if you were looking down into the car from the left front fender to the right door:

14b2g76.jpg


Looking straight down at it, if you're standing next to the cowl hat on the passenger's side of the car:

2cxjhie.jpg


Side view from passenger's side of the car. Part of the rocker panel flange remains attached to one flange:

25011rt.jpg


Bottom view.

2d9vgio.jpg


-Kurt

 
Awesome Kurt..... these pictures are great. I wonder how were they supposed to drain any water that gets inside the box. There is that opening on the rear side where water can go in/out but I am surprised that it doesnt have a drain hole on the fender side where I am sure water can stay.

Also, i assume the firewall/floor pan follows the contour of the box all the way to the top or do they separate? I see that the top has a lip where the welds are which is at a slightly different angle. So if the firewall pan separates there at the top edge i guess that any water that gets in that dead space between firewall and box will not drain easily and cause issues.

Edit: after looking in the car last night I noticed that the firewall does appear to follow the contour of the torque box. There is a slight change of slope on the firewall in this area. I was also able to clean the area better and saw a row of spot welds that tell me the top edge of the torque box.

1971 M-code Mach 1

 
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Run into another issue last night. The bottom of the rocker panel at around the middle of the floor is bent badly. It looks like it was hit from underneath or something. The area circled in the picture is wavy and bent inwards. This is making it challenging to fit the new pan because it hinders the pan from being tight against the rocker panel - specially at the back and front due to the bend in the middle.

This edge of the rocker seems very stiff. When I use a hammer it doesn't budge. I have been a bit hesitant to hit too hard. What's the recommendation here? Since the top of the rocker is cut open, should I place some kind of heavy piece of metal down there to hold the back of the panel. I don't have a dolly.

The wavy deformed area correspond to the area where the top of the rocker was cut. That makes me think that at some point something happened here and they tried to fix it. Maybe a rock or something got wedged underneath in this area.

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They probably tried to jack the car up on the pinch weld. Mine was all deformed. I took a hammer and dolly to it. Or if you have 2 pieces of angle 2ft long, sandwich the seam in between and put a couple of c clamps on the angle iron and tighten them up. that should help bring it back into shape. If you have a harbor freight around your place pick up their hammer and dolly set for body work. I got them for 19 bucks or something like that with a coupon and they work great.

http://www.harborfreight.com/7-piece-body-and-fender-set-31277.html

 
They probably tried to jack the car up on the pinch weld. Mine was all deformed. I took a hammer and dolly to it. Or if you have 2 pieces of angle 2ft long, sandwich the seam in between and put a couple of c clamps on the angle iron and tighten them up. that should help bring it back into shape. If you have a harbor freight around your place pick up their hammer and dolly set for body work. I got them for 19 bucks or something like that with a coupon and they work great.

http://www.harborfreight.com/7-piece-body-and-fender-set-31277.html
Thanks. This gave me the motivation to hit it hard with the hammer. I didnt use a dolly but i had a heavy 2" steel rod that i used as backing. It was pretty easy and now it looks straighter. The bottom of the rocker was repaired and repainted at some time so a lot of that paint came off.

1971 M-code Mach 1

 
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The bottom of the rocker was repaired and repainted at some so a lot of that paint came off.
I'm starting to wonder whether your car was hit on that side. It'd explain some of the missing metal - removed to help pull the rocker back into shape, perhaps?

At any rate, have the bottom of the rocker epoxy primered and resprayed. That pinch weld is a prime spot for trapping water and road grime leading to rust. The good old ounce of prevention, essentially.

-Kurt

 
The bottom of the rocker was repaired and repainted at some so a lot of that paint came off.
I'm starting to wonder whether your car was hit on that side. It'd explain some of the missing metal - removed to help pull the rocker back into shape, perhaps?

At any rate, have the bottom of the rocker epoxy primered and resprayed. That pinch weld is a prime spot for trapping water and road grime leading to rust. The good old ounce of prevention, essentially.

-Kurt
Yeah, thats my suspicion. It has all the signs that it was hit on that side. The door does not close as smooth as the driver's either. It was probably lifted by the rockers also so it may be a combination.

In any case, i may never know so got to move forward and make it look as good as i can with what i have.

BTW, that pinch weld seems a terrible design idea for an outside part of the car.

1971 M-code Mach 1

 
Yeah, thats my suspicion. It has all the signs that it was hit on that side. The door does not close as smooth as the driver's either. It was probably lifted by the rockers also so it may be a combination.

In any case, i may never know so got to move forward and make it look as good as i can with what i have.

BTW, that pinch weld seems a terrible design idea for an outside part of the car.

1971 M-code Mach 1
Too bad I scrapped a pair of '73 floorboards with good rocker sections in them; they may have been handy for your needs.

Tons of cars - even today - have that pinch weld on the bottom. Even body-on-frame vehicles. Dead simple to have a spot welder fuse the inner rocker to the outer with this method.

-Kurt

 
Okay, so another chapter in my saga just opened up. Last night I finished hammering the hell out of the inside of the rocker panel to make it look as straight as possible. The floor pan now fits very good. However, when I look on the outside I found a big surprise. I guess the exterior of the rocker has something like a 1/4" thick bondo layer that cracked while I was hammering the inside (see picture). I am starting to get an idea of what's going on here. As mentioned earlier, the car appears to have been involved on some type of side accident. My guess is that the rocker was hit pretty good. Given the thick bondo layer I assume that the rocker is very wavy or wrinkled. On the bright side, I saw no rust on the sheetmetal on the area where it cracked.

Now comes the question. I can patch this crack now and worry about it next year since I don't think I will have the time to deal with it this winter, or should I get to it now. What would be the best way to go about it? My thinking is that I will have to strip the bondo of the whole rocker, but obviously that's easier said than done because I will be opening a can of worms. I am expecting to see the rocker in bad shape, otherwise why will they have used so much bondo. On the other hand, the inside of the rocker looks relatively straight when I look through the opening on the top (see previous posts). Will it be easy to straighten/repair a rocker panel or will it be better to replace a section of it. I have never worked with bondo before so I don't think I want to form the bondo back into rocker panel shape.

I welcome your ideas, thoughts and encouragement for an easy short-term fix and for a more permanent fix.



Too bad I scrapped a pair of '73 floorboards with good rocker sections in them; they may have been handy for your needs.
Yes Kurt, after my latest find, I guess the rocker section would have been useful.

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You're in it this far. Do it right. Take the grinder (EDIT: By that, I mean angle grinder with WIREBRUSH...) to it and find out. Since it's on the argent part of the car, it should be relatively easy for a shop to respray it too.

Remember, your rocker is a significant part of what keeps a unibody car together in the middle. Don't even think of skimping here.

-Kurt

 
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You're in it this far. Do it right. Take the grinder to it and find out. Since it's on the argent part of the car, it should be relatively easy for a shop to respray it too.

Remember, your rocker is a significant part of what keeps a unibody car together in the middle. Don't even think of skimping here.

-Kurt
Yes, it makes sense. But here is my dilemma. After further looking inside the rocker panel I can now see the waviness (picture shows inside of rocker panel). I had a flashlight shining from the side to highlight all the bumps. As you can see the rocker is very bumpy and I don't know if I can make it straight just by massaging it. I don't see any rust on the inside and the metal behind the chunk that came off looks good. That said, if I remove all the bondo how am I going to fix it without smoothing it out with bondo again and go back to square one. I checked the bottom of the door and it looks straight and undamaged. It could be that the door was replaced. However, whatever happened on that side may have been from below because the top half of the rocker is in good shape. The damage is only on the bottom half facing out.

I used a paint thickness measurement magnet to get an idea of the amount of bondo. The wavy area of the rocker, which is about 2 feet long has a lot of bondo. The rest of the rocker has areas with "thin" layers of bondo, the same for the door and fender. What I am afraid of, is that if I strip all the paint and bondo I will need major body work to shape it, which I may need to outsource and pay for. I know is not ideal, but unless there is permanent fix I can do myself, I may have to settle with a temporary fix and then in a few years save for a bigger fix.


As a permanent fix I see that the outer skin of the rocker is reproduced.

http://www.jegs.com/i/Sherman-Parts/455/469-00R/10002/-1?parentProductId=1943411

I guess I would need to cut the 2 foot section and weld the repro in place. While this sounds doable I am afraid that I may need to add bondo to make all fit. Plus I don't know if my welds are that good to be used in an exterior panel.

Has anyone has used the Sherman rocker panel? I am curious to see a picture from the top. This panel seems very cheap, $24 at Rockauto, I wonder how good of a repro and if it matches the thickness.

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Now it all makes sense. Car probably wasn't hit from the side, but might have been beached badly on a tall curb. The cutout in the rocker is part of the access the body shop made so it could pound the rocker back into place. I notice evidence of holes made for a slide hammer.

At any rate, they did a ****** job of it, just like 90% of the work we find on these cars from back in the day.

I was going to lead up to the suggestion of sectioning in a replacement rocker section to replace the damaged bits (better be 100% sure you have the car jigged up so that the rocker isn't supporting the weight), but as I recall right, your welder is an 110v unit, correct? Not really ideal for burning in a structural piece such as a rocker patch.

-Kurt

 
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Now it all makes sense. Car probably wasn't hit from the side, but might have been beached badly on a tall curb. The cutout in the rocker is part of the access the body shop made so it could pound the rocker back into place. I notice evidence of a slide hammer having been used.

At any rate, they did a ****** job of it, just like 90% of the work we find on these cars from back in the day.

I was going to lead up to the suggestion of sectioning in a replacement rocker section to replace the damaged bits (better be 100% sure you have the car jigged up so that the rocker isn't supporting the weight), but as I recall right, your welder is an 110v unit, correct? Not really ideal for burning in a structural piece such as a rocker patch.

-Kurt
Actually, the welder is a 220. If the subframe connector were welded in place would jigging is still necessary?

1971 M-code Mach 1

 
Wow lots of work going on there!

It looks like you have lots of good metal there, I wouldn't cut it out my self

If you have a good dolly set you can bump that out.

Use the other rocker panel to make a template of the profile

That and a good straight edge is all you need

Who care if it takes two days to get it, as this will be a lot faster than a patch work quilt job

If you haven't bumped out dents before then watch a couple videos of the hot rod guys and bang on some sheet metal before you have a go at it

You can weld up the holes from the puller

Also find the video Q made on using a shrink disk so that you can fine tune the spot if you stretch it to much

If you have patience you could fix that with next to no bondo

This is what I would try first

Good luck

 
Wow lots of work going on there!

It looks like you have lots of good metal there, I wouldn't cut it out my self

If you have a good dolly set you can bump that out.

Use the other rocker panel to make a template of the profile

That and a good straight edge is all you need

Who care if it takes two days to get it, as this will be a lot faster than a patch work quilt job

If you haven't bumped out dents before then watch a couple videos of the hot rod guys and bang on some sheet metal before you have a go at it

You can weld up the holes from the puller

Also find the video Q made on using a shrink disk so that you can fine tune the spot if you stretch it to much

If you have patience you could fix that with next to no bondo

This is what I would try first

Good luck
Interesting. Two questions here:

. The thickness of the bondo seems thicker than the bumps. Therefore, if the rocker is made straight it may not align with the fenders. I dont know for sure, but if thats the case what would i do? Thats one of those worms in the can that i am afraid of.

. The slot that is cut on top of the rocker is about 1.5" wide. Would that be enough to have access to the inside to bang it?

1971 M-code Mach 1

 
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