Rust Repair on a 47-54 Chevy 3100
Be ready to get dirty. Once I had the body apart I was able to see what I had, the rust was worse than I thought. My Cowls (The part where the fender attached to the outside of the cab) was shot, my floors and toe boards were shot. My Cab Support was rusted through where the frame bolt goes in the front, My Cab corners were shot.
Replacing the Floor in a 47-54 Chevy
I purchased new Floorboards, Toeboards & Trans Tunnel and they fit great, plus these came with a Trans tunnel. I laid these out, penciled them off, cut out 1 inch inside the pencil mark, then placed the new ones in. I then attached with self-tapping screws about every 3 inches or more as need to pull the steel down level. I then tacked them every inch or so with a flux welder. I removed the screws one at a time after welding and then filled the holes with weld.
47-54 Chevy Cab Support Repair
My front cab supports had some rust issues, I measured them and then bought a 1/8 flat steel piece to match the bottom measurement and welded it to the cab supports. This strengthened them better than original.
I decided not to replace the cowl and cab corners. Since I am doing the patina look, it wouldn’t match. If I decide to paint the truck in a few years, I will replace all of these items as well as the front fenders.
Cab Rust Removal on a a 47-54 Chevy
I used a wire wheel to clean all of the underside of the body. I could have had them blasted, but I was afraid they might accidentally warp the panels. Once wire wheeled, I rinsed with my power washer and then sprayed with degreaser and washed again. I let them dry out in the yard… Sorry Neighbors… I’m surprised the HOA President 2 houses up didn’t bitch about it to me!
Sealing the Firewall
The firewall has a ton of holes drilled through it for various mounting items and such. I’ve seen where the proper way to fix this is to cut steel to fill the holes and weld it in. I decided that was too labor intensive for something that the engine will mostly hide anyhow. I simply bought a bunch of 1 ¼ fender washers and ¼ bolts with nuts. I put a washer on both inside and outside for the large holes and the bolt and nut only for the smaller ones. I placed 2 nuts on the inside to lock them down. I chose round flat screw heads, to look a little sleeker inside the engine bay. I also used the screw head side on the engine side, to look a bit better.
Prepping to Paint the Underbody of a 47-54 Chevy Cab
I bought a gallon of Chassis Saver paint, this is very similar to POR15, but cheaper. From what I’ve read it is very durable if applied correctly. I also read that it is very difficult to get off your body if you accidentally get it on you. I was very careful and bought a full dupont coverall suit complete with hood and gloves HERE. I also bought a Full Face Mask, I looked like I belonged on Breaking Bad. This worked pretty well, I had a bit of paint get between my wrist and glove and strangely enough a big blotch on my forehead. I was able to remove them though with lacquer thinner, since I saw it before it dried. Note: Lacquer thinner on your hands is no big deal… But on your forehead…. Sweet baby Jesus, it felt like someone put out a cigarette on my forehead! I used Frog Tape and brown paper to cover the areas where I didn’t want over-spray, I’ve had great luck with it.
Painting Under-body of a 47-54 Chevy Cab
I laid out a huge tarp in my garage and setup a fan blowing away the fumes and got after it. I made sure to get it in the nooks and crannies. I also painted the hidden part where the fenders fasten to the cab on both surfaces, hopefully this will help prevent rusting. My gun put it on way too thick, I should have bought the Reducer from them too. It was runny too, despite my taping, I got some streaks inside the bed, which I had planned to keep in Patina. I had to scrape off the paint runs. I used Gloss Black, but they have flat if that’s more your style.
It took 1 coat since it was so thick, had I purchased the reducer and been able to make thinner coats, I would have done 2. The Chassis Saver is not UV resistant, so it needs a top coat if exposed to sunlight. Obviously, the bottom of the truck isn’t, but I wanted to be safe. I went back and forth on what to use and decided on POR15 Top Coat. It really pays to take your time and read and follow the prep instructions here.
Once I finished painting the underside, I painted on 2 coats of Seam Sealer on all the welded replacement pans, firewall hole bolts. I was liberal with this stuff, trying to do everything I can to prevent further rust.
I installed new leaf springs , I took the frame to a Local sandblaster to have it blasted and primed. They said it would be done the next day…which turned into middle of next week… which turned into the middle of the following week. After the 2nd pushback on it I decided to go pick it up. They had blasted it day 1 then just let it sit in the shop, so it had flash rust all over it. I was painting with Chassis Saver anyhow, so I didn’t care. I placed it in the garage on the tarp and cleaned it up with degreaser. I taped over the general area where my cab mounts, front support and bed support would go. I then sprayed 2 coats of Chassis Saver on it. I used my compressor (only 11 gal) and a LVLP Spray Gun. It laid out nice, a little bit of paint goes a long way.