The Stovebolt Site Forums The Shop Area Paint and Body Shop AD Floor Replacement with Patch Panels

I’m in the process of replacing my floor in my AD truck and I am wondering how others approached the back of the panels by the seat riser. I can’t do a butt weld to the floor panel as there is rust holes close to the seat riser. Unfortunately the cut line must be at least to the edge of the lower flange of the seat riser where it overlaps the floor. It seems to me the easiest method (not necessarily the correct), would be to overlap the seat riser flange and plug weld or use panel bond to adhere it.

The front is going to be a butt weld but for the rear I’m looking for other opinions.

Still looking for suggestions. I’ve got the passengers side floor pan mostly removed waiting for advice on how others have joined the rear of the pan.

Not from experience (my seat riser was removed) but I think overlap and plug weld option you are considering would be a good choice.

I but welded my drivers side ,my passenger side is next but it is not to rusty there.

If you are going to overlap this works good , I have used this from harbour freight and works good so the panel lays flat if you don’t mind the overlap joint .also works good for making holes for plug welding on the edges of the panels.

That looks like a really good option, so I’m headed out today to buy one. Checked on line and they are in stock!

Thanks!

There is also this one that I seen that may be desirable depending on preference.

When I repaired the rusted areas on my floorpan... I drilled 7/32 holes in the original panel parallel to the joint, I then plug welded a piece of 1 " wide 16 guage sheet metal under where the joint was going to be. This provided a backer to the patch and helped prevent any blow through when coming back and butt welding the "seam". The "sheet metal strips are almpst unnoticable from the bottom.

I don't like the idea of butt welds on the floor pan because of road slash and grime which will invariable find its way into the seam. It may last for a good long time, but not as long as a good butt weld.

I think Carl meant that he didn't like lap weld joints, but those can work if you seal them up well. You'd want to put some good epoxy and undercoating on the bottom of the floor anyway.

If the riser flanges are in good shape, you can butt weld half way back under that. But you'd need access to the underside to do that weld. Might be a little tough with the cab on the frame.

I butt welded my floor panels in, but there was enough good metal in front of the seat riser to do that. I did have to replace the set riser flange on the driver's side as it had rusted away. Had an opportunity to use a friends metal stretcher to form the flange around the corner. That's a cool tool. I also replaced a section of the floor along the side of the riser in that area with a patch that I fabricated. I made the butt welds of the purchased floor patch panels from the bottom just under the riser flange. Here's a pic of that area on my cab floor.

Brain flatulence, often misdiagnosed as typo, or dyslexia, neither of which do I suffer...
Lap joint, indeed.

Hey, Phil, what are the chances of making a video of the entire procedure (even of the mistakes and redo's) of your floor panels. I, for one, would have liked to have seen your measuring and cutting procedure. I have watched videos on people telling what to do when replacing the floor panels or kick panels but never SHOWS how to do it. Unfortunately, in my later years, I have become a visual learner and not a listening learner (does that make sense?).

SS

I would like to see a video of a complete floor replacement . My aftermarket just doesn't seem to fit .

Some people have that ability to be able to record and narrate a video. My apologies but I am not one of those. It would be full of “Ah’s” pauses and just bad language. I have a Project Journal that will document the floor replacement and my thought process thru the entire project.

The issue with replacing the floor is, in most case’s the rot goes beyond the floor into the cowl assembly. The cowl ties into the floor, door, fender, the rocker panel and the front cab support. Lose the cowl and you lose all your measurements.

The second issue is the replacement patch panels that are available today, just don’t fit very well necessitating massaging the panel to fit your existing structure. Most bodymen recommend replacing only the rotted sections (not the entire replacement panel) so you don’t lose the existing fitted parts which help you keep you dimensions in tack.


Fortunately, my cowls are in pretty good shape so it makes replacing the floor much easier as in I’m only fitting the floor to the existing sheet metal.

You are really lucky that the cowls are not involved. I didn't thinnk mine was too bad until I dug into it and ended up replacing the lower section of the inner, outer and inner to outer cowl parts. I was lucky though because my A pillar was secure to the rocker panel so bracing the door opening was sufficient to keep everything in place. Some I have seen here are not so lucky.

Nothing will fit exactly and will need massaging. The FAM has a whole set of measurements of the cab that should be referred to.
I documented with pictures most of my repairs that included rocker panels, floor, lower portion of A pillars, inner and outer cowl,and the dreaded inner-to outer cowl piece (which needed some serious slicing and dicing to fit.
You can review those photos in the link in my signature.
No videos though. It's way too hard to video while working on something. The "AHs" and bad language that Phil mentioned can be edited out, but doing videos and editing them would turn a 5 year project into a 10 year project, IMO.
One of these days (years?), I'll get around to putting all those photos into a Project Journal.

Kevin, thanks for sharing all your photos I have been looking at them for about a month, and have gained a lot from them. Unfortunately my cowls were shot the whole lower door frame and upper a pillar with it . I would have been better off with another cab , but just not in the budget , and I have all the aftermarket parts from previous owner. Who has passed.

I finally got the panels fit to the truck and to each other which was no easy feat. I first fit the cowl then the floor, then both together. They didn’t fit together, at all. After a couple of hours, as Kevin said “massaging” the two finally fit pretty good and fit in the truck. I had to put some cuts so I could reform the edge of the radius on both pieces. Once I got them to fit , I welded up the cuts and ground down the welds.

I am happy with the results. I spent the rest of the day cleaning, and prepping the subframe and areas that are inaccessible with the floor in place. I’m ready weld in the passengers side floor. I you want read about the entire process, it’s in my Project Journal.

Are the recessed washers that fit under the front cab mounts bolts tack welded in place?

Phil, Not to my knowledge. They do tend to "rust weld" in place if they haven't been disturbed though.

Those washers weren't spot welded to the floor on my truck. They may not even have been there when I got it. Well, the passenger side wasn't anyhow. The attached picture is inconclusive, though as far as whether they were welded on.

Mine were spot welded I think in 3 spots .I reused the original washers as they are also a lot thicker than the replacement ones .

After thinking about it, the bolt hole in the floor where the cab mount bolt goes thru is close fitting and the floor support is going to be plug welded to the floor, so I decided it doesn’t need to be welded.