Floor Pan Attachment Methods

Sea Knight

SILVER Star
 
Joined
Apr 19, 2006
Messages
2,545
Location
Austin, Tejas and Laurel, Mississippi
I saw a nicely restored '74 40 at the Dallas truck show last weekend. The floor pans were attached with stainless hex head bolts instead of welds. I've also seen replacement floor pans riveted in place in a couple of 40's. Are bolts or rivets a good idea as an alternative to welding?
 
Joined
Feb 27, 2002
Messages
2,894
The floor is part of the structural integrity of the vehicle. In a crash situation, I want mine welded. Bolting the floor is a stupid way to keep from paying a welder or learning how to do it yourself. For safety's sake, just say no.
 
Joined
Feb 27, 2002
Messages
2,894
I saw a nicely restored '74 40 at the Dallas truck show last weekend. The floor pans were attached with stainless hex head bolts instead of welds. I've also seen replacement floor pans riveted in place in a couple of 40's. Are bolts or rivets a good idea as an alternative to welding?
Also, I wouldn't consider a truck with a bolted floor to be restored. Rather, a great place for a lawsuit to begin. In this litigious society, that owner better pray he never sells.
 
Joined
Feb 21, 2009
Messages
1,053
Location
Enumclaw, WA
Welding would be best unless the pop rivets were airplane quality. That takes a special tool for applying them and I really have not seen to many that have gone to that step. I have a buddy who hand scratched built a GT40 and they call for rivets so he used the airplane style. The car is freakin a thing of beauty not to mention absolutely solid with no flex. The nut and bolt that my PO did hacks me off by his cheap attempt and fixing a problem.
 

Sea Knight

SILVER Star
 
Joined
Apr 19, 2006
Messages
2,545
Location
Austin, Tejas and Laurel, Mississippi
The floor is part of the structural integrity of the vehicle. In a crash situation, I want mine welded. Bolting the floor is a stupid way to keep from paying a welder or learning how to do it yourself. For safety's sake, just say no.
Thanks. That's about what I suspected. This particular 40 had a rhino lined interior. It appeared that the floor pans were sprayed separately and then bolted into place. One of the 4 Wheel Parts guys said he thought they did it so that the floor pans would be removable. :hmm:

It was neatly done from a cosmetic standpoint but didn't seem like it would provide structural rigidity.
 

Sea Knight

SILVER Star
 
Joined
Apr 19, 2006
Messages
2,545
Location
Austin, Tejas and Laurel, Mississippi
body adhesive is in most instanced better than welding.
Would body adhesive be a better option than welding when replacing floor pans, where structural integrity is important?

I'm totally ignorant of body adhesives and their recommended uses. I do remember someone at Wimberly Four Wheel Drive telling me that they use body adhesive in lieu of welding when making small sheet metal patches.
 
Joined
May 4, 2009
Messages
77
Location
cartersville,ga.
hey guys. fwiw, i would like to shed some light on this. let me say i'm an icar & ase certified collision tech that has trained on every aspect of collision & structural repair. floor pans are not structural on a full frame vehicle. to be truthful, they're not really structural on a unibody vehicle. the structure comes from the torque box which surrounds the pass. compartment, such as inner & outer rockers, a,b,& c pillars & the roof. while i do not agree with cheesing out like this fella did, there is nothing bad about his installation. as far as structural adhesives go, i use it everyday but it has limits & is not a fix all. my rule of thumb is,(if it's welded, weld it back) in some instances, adhesive is stronger because u run a continuous bead on the panel instead of a spot weld every few millimeters, & it cuts down on seam sealers such as roof joints & over wheelhouses. the best to use is made by 3m & it's # is 8115. it takes 24 hours to dry & it takes 700 degrees to turn it loose.:wrench:
 
Joined
Jul 5, 2009
Messages
378
Location
Minneapolis
Bumping an old thread.
I'm looking at a little front fender patch and I'm considering adhesives since I'm not a welder.

I've looked at the 3M product you mention. They want about $200 for the dispensing gun and $50 for the adhesive. Lord makes a similar product, Metal Bonding Adhesive, and the adhesive and a gun run about $100 total. Any feedback on the Lord product?
 

Sea Knight

SILVER Star
 
Joined
Apr 19, 2006
Messages
2,545
Location
Austin, Tejas and Laurel, Mississippi
body adhesive is in most instanced better than welding.
in some instances, adhesive is stronger because u run a continuous bead on the panel instead of a spot weld every few millimeters, & it cuts down on seam sealers such as roof joints & over wheelhouses. the best to use is made by 3m & it's # is 8115. it takes 24 hours to dry & it takes 700 degrees to turn it loose.:wrench:
I've looked at the 3M product you mention. They want about $200 for the dispensing gun and $50 for the adhesive.
Delayed followup here, now that I finally got around to replacing my rotted out floor pans. We used a combination of spot welds and a continuous bead of 3M adhesive, which according to the specs is stronger than the traditional weld-only procedure. That adhesive is expensive as all get out, but supposedly lasts forever. I think it was $60 a tube. A couple of pics...
FJ40 Repairs 010.jpg
FJ40--DS Floor Pan.jpg
FJ40 Repairs 131.jpg
 
Joined
Aug 30, 2015
Messages
175
Location
maine
thanks for this post. i know it is way old but was exactly what i was planning on doing and now will. the reason we continuously have
to rebuild these trucks is partially old tech. adhesive is a no brainer with these trucks.
wheel wells to quarter panels sound like a good idea ? rear pan to the wells?
 
Top Bottom