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1973 K5 Floor Replacement

Tech Article

  1. noahrob
    Article/photo's courtesy of:

    1973 K5 Floor Replacement

    So, you’ve got a beater that needs a little help on the inside. You don’t want to drop the $600 bucks to RhinoLining the interior and even if you were willing to spend that type of dough, you still need to fix those gaping holes in the floor, which if you pay someone to do is not cheap. Here is how I fixed my cab floors and re-did my interior…on the cheap.

    Idea and Approach:
    I have been unhappy with the seats in my rig for a long time, but the problem was exaggerated when I put the SM465 in and couldn’t completely depress the clutch pedal anymore. I knew I wanted some Corbeau Baja SS seats, but didn’t want to mount them to a floor that well, to be honest, was structurally unsound. With that as a backdrop I decided it was time to replace my floors. Since my truck isn’t pretty to begin with, I didn’t want to spend all that money on new carpet, and the old carpet was not only completely worn out, but part of the problem.

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    Whenever the carpet got wet (which is often since my truck isn’t exactly water proof) it kept the moisture in and pressed against the floor boards which over the course of 30 years simply disintegrated. I took all of this information in, did a little research on CK5 (the research for this project alone was worth my $30 registration fee) and decided I wanted the end product to be a roll on bed liner, no carpet and no muss and fuss.

    I realize it is not the only product out there, but based on everything I read, including ease of application, chip resistance, cost, and durability, Herculiner seemed to be the way to go. However, I wanted to make sure that my new floors lasted more than two years, so based in large part on CanmoreK5’s review of Rust Bullet I decided to coat the floor with this product before applying the Herculiner. So working backwards, I knew the topcoat, and the undercoat, now it was time to decide on floor panels.

    After reading literally 100’s of posts (another shameless plug for the benefits of becoming a paying CK5 member) about how good or bad LMC vs. JCWhiteney panels were and why I should just use sheet metal instead of per-formed panels I decided to go with LMC floor boards. I purchased both the front and rear pieces for both the driver and passenger sides and with these things sitting in my garage I was ready to go.

    Materials and Tools:
    Maybe it is a sign that I am getting more mature or smarter, or maybe I am just tired of spending all my free time driving around picking up what I forgot, but I am now a firm believer in “measure twice and cut once”. Instead of diving in and then realizing what I didn’t have, I planned it out, made a list and got all my supplies before I started.

    Here is a list of the supplies I needed:
    1) Gloves
    2) Acetone
    3) 1 Gallon Herculiner
    4) 1 Quart Rust Bullet
    5) Wire Brush
    6) 100 Grit Sandpaper
    7) 2” Paint Brush (lots of them)
    8) Extra 2” Roller (didn’t need it in the end)
    9) 4” Grinding wheels
    10) 4” Cut off wheels
    11) 4” Wire Brush
    12) “No rust” spray paint
    13) “Rustoleum” spray paint
    14) About a case of Diet Rockstars (double shot) just for good measure!
    15) Lincoln SP 125 (2lbs .30 hard wire and 75%/25% gas)
    16) Various Hammers, Cold Chisels, and pry bars
    17) Ear plugs, goggles, and leather gloves

    Floor Removal:
    After taking out the seats, the roll cage, and ripping up the carpet, I discovered why my floor moved so much.

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    I started by making a series of small cuts using the 4” cutoff wheel so that I could create a look through panel and see what was under there as I had no idea if there were cables, wires, fluid lines or what. As it turns out there wasn’t any of that stuff, but better safe then sorry.

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    Once I was confident that I wasn’t going to destroy anything, I cut out the flat part of the floor on both sides and then used the 4” grinding wheels and wire brush to remove the rust.

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    After grinding as much of the rust off as I could get to, I painted everything I could see with a combination of “no rust” (at $13 a can, I only bought one and used it on the worst parts) and “Rustoleum”.

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    Floor Replacement:
    Once everything was cleaned up, it was time to put the new floors in place. (Note about the LMC panels; since the panels are designed for all Blazers from ’73 to like ’90, the rear panel is way longer than need be so that in post ’77 trucks you have that space behind the seat. CamoK5 noted that you could line the panels up with the tranny hub and then trim them down to size.

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    I cut the panels down to size and then started trimming them to fit as best as they could. I made many very small cuts instead of one big one so that I didn’t totally botch it. In the end, the fitment was not perfect, so I decided to use the combination of heat from the welder and a ball peen hammer to persuade the panel into place.

    Before I started welding though I used the grinder to remove the paint from the panel and where it would weld to so that I would get cleaner welds and not have to burn off all that paint. The process went, get the panel about where I want it, tack a corner in place, smash the edge down with the hammer, make my next tack, repeat…As the metal got hotter, it was easier to manipulate and I worked my way all the way around making many tack welds. Once I got the rear piece in, I turned my attention to the front half of the floor. I basically repeated the whole process; I cut old the old metal, cleaned it up as best I could, fit my new piece and tacked it in place.

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    Once I was done with the driver’s side I moved to the passenger side and did the same thing. After everything was in place I went back and patched any gaps and welded the entire seam of the new floor.

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    One note about this, I am not a great welder, but I quickly realized that I could only get 1-2” runs before it got too hot so I moved around the panel, a lot like torqueing on a wheel, weld front left then rear right then front right then rear left, etc…

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    Rust Bullet:
    Since there is such a good write up on this all I will say is that I washed the entire tub with Simple Green and soap, then sanded and/or wire brushed (hand and 4”grinder) it, then washed it with acetone twice before I started with the Rust Bullet, which I applied according to the directions. I will say that the first coat took me almost 3 hours to apply, I was very careful and since I didn’t think 1 quart would be enough, spread it out pretty thin. Turns out 1 quart was enough for 2 coats including the tailgate and I still had some left over.

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    Again, research on CK5 led me to this product, the application of which was simple. After I let the Rust Bullet set up for the appropriate amount of time, I washed the entire tub with acetone, let it dry and then applied the Herculiner according to the instructions. I dabbed it on all the seams with a brush and then went back and put down a very thin layer with the roller. I was afraid that 1 gallon and 1 quart wouldn’t be enough so I put down a super thin uniform coat.

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    I let that first coat setup for 4 hours and then went back and put the second coat on as thick as I could. Turns out 1 gallon was enough for two coats including the tailgate.

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    Conclusion and Lessons Learned:
    As far as looks go, I think it looks great, 100x better than where I started! However, since the seats aren’t in yet, I don’t have much to conclude (truck is just sitting in the driveway). We were able to rip some of the Herculiner off the floor by dropping the roll cage down the edge of the wheel well, but I am not too surprised at that.

    Here is what I learned – I would have used sheet metal instead of LMC panels, cheaper. Just like everybody said, Rust Bullet and Herculiner do NOT come off your skin. Herculiner can go flying off the roller and stick to your face without you knowing and it does NOT come off (this actually sucks pretty bad). Non-Nitrile gloves like dishwashing gloves melt when covered in acetone. Cheap Chinese made grinding wheels explode, often, and can hurt when they hit you, especially in the face. 1 gallon of Herculiner will cover the entire tub, including tailgate, with two coats. 1 quart of Rust Bullet will cover the entire tub, including tailgate, with two coats. Finally, if you have 2 4” grinders running non-stop for 90 minutes in my neighborhood, the cops will come to your house and tell you to shut up!
    bix likes this.

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  1. Gorillajeep
    nice wright up! What gauge sheet metal would you have used?