Interior seam sealing questions

[DAVEN1256]

I am about to do some interior seam sealing and have some questions. I'll put each question after a photo where I have circled the area I am talking about in red. All of these pics except the last one are of my original factory seam seals. I now have a new full main floor, new full trunk floor, new inner and outer wheelhouses, and new inner and outer rockers.

 

Why did the factory only seam seal the front seat frames along the sides and not along the front and back? If water got to the floor, it's still going to get under the seat frame from the front or the back. I don't understand the logic of just doing the two highest sides. I wondering if there is a reason I should not seal mine all the way around.
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Again with these two pictures, why were these rear seat supports only sealed on two sides? Water can still get under them.
Is there any reason they should not be sealed all the way around?
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Where the front seat frame is welded to the rocker, how did the factory get a good seam seal between the rocker and the floor underneath the seat frame where that joint is inaccessable? They obviously seam sealed after the seat frame was in place.
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I was told that this brace on the floor only came on convertibles originally but now comes on all reproduction floors. My coupe did not have this brace on it's original floor. Did this piece get seam sealed originally on the convertibles? I assuming it probably did since everything else welded to the floor got at least a partial seam seal. And again here it will be difficult to get seam sealer into the floor / rocker panel joint where this brace covers it.

Thanks.....Dave

[firstgenaddict]

You can buy it at the GM dealership it is called pumpable sealer.
A good alternative that looks extremely close is Evercoat brand undercoating, comes in 1 Quart cans and you can use a chip brush to brush it in, you may need to pour it into a open can and allow some of the solvents to evaporate so it will be thicker.

[DAVEN1256]

Thanks for the suggestion the seam sealer.

What I was really trying to get to is how to seam seal all the brackets and braces that are welded to the floor. On all four sides.......or on just two sides like GM did it......or maybe not at all. I don't undrstand why GM only did two of the four sides on all of these. It's easy enough for me to just do all four sides but before I did that, I wondering what the reasoning was for GM only doing two sides and leaving the other two unprotected.

And also, how the floor to rocker panel joint got sealant in it where that joint is covered by the front seat brace.

Thanks........Dave

[HawkX66]

Thanks for the suggestion the seam sealer.

What I was really trying to get to is how to seam seal all the brackets and braces that are welded to the floor. On all four sides.......or on just two sides like GM did it......or maybe not at all. I don't undrstand why GM only did two of the four sides on all of these. It's easy enough for me to just do all four sides but before I did that, I wondering what the reasoning was for GM only doing two sides and leaving the other two unprotected.

And also, how the floor to rocker panel joint got sealant in it where that joint is covered by the front seat brace.

Thanks........Dave

I would only seal where you found factory sealant. If water were to get under your carpet and was able to work its way under the sealer somehow, you don't want it to get trapped. It needs to have a way to get out and dry.

[DAVEN1256]

Letting water escape makes sense but I wonder why then, with the seat frames for example, they didn't seal the two lowest sides (the first place water would get in) and leave the two high sides open for water to evaporate out of if the seam seal failed.

[HawkX66]

Letting water escape makes sense but I wonder why then, with the seat frames for example, they didn't seal the two lowest sides (the first place water would get in) and leave the two high sides open for water to evaporate out of if the seam seal failed.

I would look at it this way, would you rather have a roof or a water tight basement if you were trying to keep dry in a rain storm? You want to protect the part from getting water in it in the first place, but in the event it finds a way in, which it always will, you want to have an exit path.

[ko-lek-tor]

I agree with Hawk. Daven1256, you are thinking if water was coming up, as in a flood. Hawk's analogy of water dripping in makes sense to me. This reminds me of a Smokey Yunick response to modifying Big Block oiling systems. He said, Chevrolet had a team of engineers and spent countless hours and dollars developing an excellent oiling system and some engine builders come along and ruin the system, reffering to putting a High Volume pump and pumping the sump dry. There must be some sound reasoning, I figure, to why things were done a certain way. I strive to replicate what was done originally and don't try to re-engineer or over restore with the only exception of applying some extra painting of areas prone to known problem areas with hopes of keeping the car from premature deterioration (rusting) that occured from lack of painting or protecting  on original assembly IE: painting inside of rockers, bottom of inside doors and 1/4 inside, inside rear fender area and the inner subframe. Maybe this is considered over restoring to the purist, but it is bad enough to restore a car once, much less, go back and having to restore car again.

[DAVEN1256]

First off, I appreciate everyone's opinions and advice.

In regards to GM having a sound reason for doing what they did, my first thought is to agree with that. If that's the way they did it, then that has to be the best way to redo it.......But then my second thought is that these cars weren't built at the factory to last forever. "Planned obsolescence!" They were to made to eventually wear or rust out so the consumer would buy a new car. That's why I am questioning why some of this factory seam sealing was done the way it was.

We all try to make improvements over what the factory did in some areas so the work we do will last. I am hoping for my car to last another 25 or 30 years. My long term goals for the car and what the factory's long term goals were are different.

In this picture, I am not sure what the seam seal circled in red is supposed to protect unless you knocked over a bucket of water on your transmission tunnel. I would think that any water that leaked under the carpet would get to the areas circled in green first and wick right into those joints where it would probably stay. I would quicker think you would seam seal the areas in green before you would seal the areas in red......Of course, I could be dead wrong.  I'm still scratching my head!



Dave

[KevinW]

The red section was probably to protect the rough edges from abrading the carpet.

[firstgenaddict]

The areas in green are pass through, liquid in the front would completely run through the channel to the rear floor boards. Use compressed air and blow through them if you haven't already.

I would be much more concerned with sealing the seams where the rockers and the floor boards meet opposite the areas you are pointing out.

[69 Zee]

As an ex Mechanical Engineer of 12 years and looking at it from an engineering side I would have to agree with James and Kevin.  Most likely served as a dual purpose to protect the edges and as a pass thru in case one did take on a little water.  Much easier to clean and absorb as water could be pushed thru to the lower sections.  If Fisher Body had chose to seal it completely up then there would be a pool of water sitting under the seat if one decided to try and cross a lake  

As far as the seat frame against the inside rockers.. Do you have your old floor ?  Then you could play around with that section and take it apart.  I'd be curious to know if Fisher Body maybe squirted a bead of sealer down the inside of the rocker edge just before the seat frame support was put down.  Something you might want to do to your new floor.

Hey consider yourself lucky that you had any sealant down at all.  Here's a pic of my driver/passenger side seat frame support (against the trans tunnel).. there was no sealant along the top edges on either side     I also have sealant in areas that it shouldn't be.  From either the gunmen pulling out of the car and bumping against the floor or they decided to clean the tip of their gun/brush  

Also remember this stuff was thrown down fast using a pressure gun w/brush tip.  No two are the same.... just close.

[firstgenaddict]

IT was a pumpable sealer that flowed into the crevices and voids.

2 - 1qt cans of evercoat undercoating usually will do the job.

[69 Zee]

IT was a pumpable sealer that flowed into the crevices and voids.

2 - 1qt cans of evercoat undercoating usually will do the job.

James,  Correct me if I'm wrong.  Maybe in some areas it was but wasn't it applied by a line worker using a pressure gun with a brush tip ?  He just simply pulled the trigger and the gun along the areas to seal.

[firstgenaddict]

Yes, I have seen two there was the beige and the black/blackbrown that went into the seams down by the floors it has a much lower viscosity than the beige, it flowed, you can tell by the way it pooled and the lack of tooling (brush) marks evident in the finished surface vs the heavy tooling marks apparent in the beige for example across the firewall etc.

Here is the black survivor floor when we cleaned the car out.
  






Here is the pass front floor board where it meets the rocker in the pass front footwell. See how it is almost poured in?




Not a first gen but this is a 2nd gen I did about a year ago, prime then seal then color.

[DAVEN1256]

Thanks to everyone for their opinions and thoughts. I am sorry it took me a week to get back to this.

Based on what everyone has said,  I am going to just replicate what the factory did and not add anything extra.

I still have two questions though............

1) What to do where the seat frame meets the rocker. I see what the factory did but don't know if that black factory sealer flowed down and completely filled the floor / rocker seam under the frame. I have been using 3M sealer out of a caulking gun and it is definitely too thick to flow like that. I have no idea if the factory sealed that area before welding in the seat frames. I want to make sure something gets into that seam. I don't have a good feeling about just doing the contact area between the top of the seat frame and the rocker and not getting anything under that joint.



2) How did the factory seam seal this brace? This brace did not come on my original floor, so I have no pictures or any reference that tell me how it was seam sealed at the factory. Was it like the seat frame.........just the sides with the front and back edges left alone?



Thanks..........Dave