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Floor replacement questions. Which way is best?

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I had my car at a shop to get the floors replaced, they completed one side, then their welder quit and my car sat at the shop for two years.  I took it to another shop and they finished the other side.


Now the two sides look very different.  I'm wondering which is better and if I should do anything.  Should I smooth out welds, apply seam sealer, etc. 


The original shop did not use seam sealer, they welded a continuous bead around the whole panel.  The second shop, it looks like they did spot welds and then used seam sealer.  I could probably take it back to the second shop and ask them to improve it, or I could clean it up myself, but I don't have a welder. 


Any advice is appreciated.  I have posted several photos below, I have numbered the photos, it should be obvious which side is which.  I want the car to last a long time as well as look good if a potential future buyer puts it on a lift to look at it.




























Edited by robotbbq

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Welcome to the forums.


When you have two options, one is better then the other. One method cannot be bester over the other after all. I point this out because it is a forum rule, no option is best. There may be an option better suited for a certain situation to a certain individual, but best is arbitrary and not worthy of arguing over.


As a general rule: if the welds don't affect fitment with a panel, it would be advisable not to grind them down. Some of those welds look quite boogery, which usually implies low penetration. That in turn means if you grind it down the panel can just come undone at the seam as it was a poor job of fusing the material.


The quality of the job depends on how well the welds penetrated. A whole continuous bead will be useless if penetration was low and the panel falls off. Similar with the stitching method if the tacs are weak the panel can easily perforate and separate. The problem is it is difficult to judge a weld hidden under paint even more so under seam sealer. The visible beads don't give me much confidence though.


Personally I used to like welding a bead all the way around, but it is very time consuming and has a very good chance of warping, that's how I did my car the first time, but when I had to cut it out it out to shift my floor it took forever to grind down all the welds. 


My current preference would actually be somewhere in the middle, about 1/2 an inch to an inch long seams with gaps, the gaps can be filled in with seam sealer to keep the joint water proof. Takes about half the time compared to filling in the whole panel, also introduces less heat if you move around, and as long as the penetration is good will hold just find. Second time I did it I stitched and seam sealed.


So to answer your question, it depends on how well the panels are fused. The thing to consider is that cars do flex a bit. If you put all that heat and make that one part stiff, there is a chance that as that part cools or as it is in service it can pull at pieces that aren't as stiffly connected.


If you can't weld then not much you can do about it unless you have the funds to take it to a proper body shop and have them have at it, but most body shops are more panel replacement places, not too many restoration places in service. As long as the second place you went to didn't use seam sealer to hide their work I would say the second place did a more favorable repair. I would say you should still seam seal the welds from the first place as it looks like it is fairly raised which means most likely pin holes are present which can cause rust to start forming if paint did not cover it well.

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The floor is supposed to move the driver/passenger away from a side impact, so I would have done full welds on the sides and spot welds along the front and rear to best mirror the original design.


Agree with above though, that welding job does not look the best - also, the beads holding the frame rails on seem to be few and far between.

Edited by morbias

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Agree with above though, that welding job does not look the best - also, the beads holding the frame rails on seem to be few and far between.

I noticed that too. I'm only a novice welder, but my gut is telling me that those welds need improvement. And I'm quite certain the frame rails need more frequent welds, and they should be spot welds.


The original floors along with the trans tunnel are one big piece of metal, so the problem is that if you replace the floors, you can't do it 100% factory. If I were replacing the floors, I would drill out the spot welds on three sides (front, rear, along rocker), and slice through the trans tunnel side with a grinder. I would reattach the new floor pan with spot welds on those three sides, and as for the fourth side, it's a little up in the air. I've seen guys make a flange, and spot weld the floors in like factory on all four sides, there's the option of butt-welding it in, and I've also seen people overlap the two a bit, and seam weld both sides. Personally, I think I'd go for option 1.


One last thing - as a general rule of thumb, if it came out with spot welds, it should go back in with spot welds. I think the guy at the first shop you went to didn't know what he was doing. I can't see what the second shop did since there's seam sealer over the welds.

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Oh wow, way to go guys. I didn't even notice the frame rails in the back. Unless it is a lighting effect that appears to be a fairly substantial gap visible in picture 8 with only the smallest of tacs holding that frame rail in. 


That makes me really wonder what is under that seam sealer now. 

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Now you made me go back and look harder. Picture 12 is worrying. I don't know which side is which, but I think I see exactly one tac weld there. Not even a bead. Just a tac. WTF. Nice big gap between the rail and the floor there too on the right side of the picture. Kinda suggests there's nothing holding the two together.

Edited by rturbo 930

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