Floor pan seam sealer splitting

[stroked408]

I'm currently replacing the carpet in my 70 Challenger and I noticed the area right behind the gas pedal, where the seam sealer is applied, has a decent size split. The floors are very solid, only the smallest of surface rust from a damp carpet during the previous rains. Anyway, has anyone seen this happen with their car before? There is no body or frame damage on this car. What would you do? Apply new sealer or have this welded? I'm the second owner of this car, it's was built at the Los Angeles plant and was from the SoCal area it's whole life.

 

[scar426]

Others smarter than me will chime in I'm sure, but Houston, you have a problem there! That gap is way too large to just seam seal and to me in indicative of some rather serious panel separation. But again, somebody smarter than me (and there are MANY, lol) might chime in later saying it is perfectly fine and to just reseal it.

 

[stroked408]

Here are pics from the underside of the car.

 

[scar426]

Here are pics from the underside of the car.

I assume pic 2 is other side. Much more manageable gap for seam sealer. Yeah, at a minimum, clean it all up, clamp it all back together, maybe some spot welds (eaiser to remove if you need to do a whole floor pan later than a full weld along the seam) and re seam seal it. Good luck!!

 

[budascuda]

Has the car been on a frame pulling machine?
I once saw something like that on a 66 Toronado, .The damage was sevier and the cab was pulled too much. I searched for signs of a bad accident and man alive, I found it....
I washed my hands off it.
hopefully, in your case it's only dried up seam filler.

 

[AUSTA]

I would check the frame rails also the firewall supports connecting the frame rails to the firewall what size engine is in it

 

[cuda joe]

the car might have been used for racing lots of horse power big slicks cars twist I have seen it before what i would do is at the big gap by gas pedal clamp it together and weld ,,you can weld from the inside 1/2 inch welds an inch apart do one at a time and let cool remember the other side underneath gets hot too watch out you don;t set anything on fire. seamseal there and where ever the seam seal split paint underneath sand metal and burnt paint you could just brush it on it will be ok

 

[cuda joe]

one more thing have a buddy watch the under side and use compressed air blow the weld area after each weld

 

[70chall440]

Lots of variables and unknowns, its possible (although not probable) that this was a very bad fitment at the factory and they tried to fill it with seam sealer which over time cracked, or its possible that the car was beat on hard back in the day and that caused this issue. I would be trying to figure out how to get those 2 panels back together and then do exactly as @cuda joe suggests. If you can get them back together and welded it will be fine.

 

[stroked408]

I appreciate everyone’s input. The car still has it’s original 318/904 w/ a 7 1/4 rear, so no hard racing on this car. I looked under again and noticed that the frame for the torsion bar is a little tweaked, but I’m not entirely sure this would be the cause. Either way, I’ll have this remedied soon by suggestions offered up cuda joe.

 

[ted s]

appears to have been wrecked

 

[moparlee]

I appreciate everyone’s input. The car still has it’s original 318/904 w/ a 7 1/4 rear, so no hard racing on this car. I looked under again and noticed that the frame for the torsion bar is a little tweaked, but I’m not entirely sure this would be the cause. Either way, I’ll have this remedied soon by suggestions offered up cuda joe.

I would say more than a "little tweaked", that car took a hard hit. Look at the gap where the frame rail is attached to the T-bar support.

 

[cuda joe]

ouch I;m sorry looks like someone ran over a big rock thats what pulled the seam apart to fix it right that support wll need to be pulled forward then cut out and new one welded in. a restoratoin shop will be the best bet it;s a lot of work.depends how involved you want to get .or you can do nothing that alone won;t affect how it drives I have seen other members take on really big projects i got to hand it to those guys

 

[budascuda]

Not a rock, a curb!

 

[Steve340]

There are under body measurements in the factory service manual. It may pay to have a good look at the problem and measure so you know what to move before you do any welding.
It may be easier to rectify the actual problem than do a patch up job. You know were it once was will be better to move it back and then weld.

 

[enforcer505]

I would wire wheel the whole seam to see whats up. Looks like age and stress has been a factor. I just did this seam on my challenger its a common problem along many things lol good luck.

 

[340challconvert]

It has already been intimated regarding the potentiality of serious damage from a previous incident, I would get the engineering frame specs (readily available) and have your car put onto a frame machine and check out the frame specs against what you have. The separation along the visual seams and your mention of a "tweaked" torsion bar would also worry me. This needs to be assessed, corrected and repaired in keeping you safe. Just my thought on this!

 

[Rons340]

Unibody cars are unique in that every joint and seam supports something. all of the seams and welds are important in retaining the integrity and strength. Even though it's a low horsepower 318 the torque, or stress of even a minor mishap can cause damage.

Looking at the photos, if it was my car I would want the opinion of a frame specialist and let him (or her) put it on a frame rack and compare the car to the specs in the factory service information. Mopars have very distinct and easy to locate reference points on the under side of the car to measure by.

It may not be as cheap as just stuffing it full of seam sealer but it is absolutely a safety issue at this point and should be addressed. Besides that, the car is too rare to just let it go.

Please let us know what you discover if you can.

 

[Ronbo73]

Looking at the pictures you can see that the car took a hit on the drivers side torsion bar support and that is the reason the driver side floor has separated at the seam. There are multiple wrinkles in the transmission hump that were caused by the collision the car has been in. That part of the floor has been shifted back slightly pulling the seam apart.. The car may need to be placed on a frame machine and pulled back into shape. Do not fill the seam or try to weld it back together until the car has been straightened.

 

[budascuda]

"Besides that, the car is too rare to just let it go"

Or, you can let somebody else have the headache! so long as you are upfront and honest with them
I know anything can be fixed, but damages like that, to me , are off putting, especially if I had to spend alot of money to restore it. Jmo