The Stovebolt Site Forums The Shop Area Paint and Body Shop Undercoating: from the Factory??

When I remove the undercoating from a 1956 1300 I noticed that there isn't any primer underneath, which makes me ask why not? I'm sure there is suppose to be primer or paint on the bottom of the cab, but I'm wondering if perhaps GM would skip primer if they were applying undercoating, if they even would apply undercoating at the factory? Any thoughts?

There's supposed to be, says who ? It's more like you would expect that to be the case, but I have noticed the lack of paint on the underside of a lot.
I think a lot of what we see does not reflect how the build sheet says but more of what just happens on the line that will make it out the door.
I'm just glad they are a lot better today than they were back in the 50's and 60's.
Dan

Undercoating was dealer applied. I can't say a vehicle "never" came from the factory with it applied but I never saw one when I was working in dealerships.

I had always thought that undercoating was a dealer applied option. It seems that perhaps primer/paint on the underneath of a truck wasn't considered important in 1956. We had been planning on removing the undercoating and after proper preparation painting it with grey POR 15 then a coat of red-ish brown paint to replicate a primered look. That should pass for original?

"pass for original"? sounds shadey from the pic of the underside of your hood I'd say you have a truck that's had at least one repaint, the hoods didn't get painted on the inside, just had a bit of color overspray around the sides at most, and the primer then was a satin black, like EDP, not red-oxide

no tellin if you removed any primer along with the undercoat, or if the chemical composition of the undercoat did it, but although the underfloor on most trucks didn't get much attention, it would have gotten as much primer as the grunt swinging the spray gun felt like leaning down to give it, doubt they laid on their backs, and the cabs went down the line right side up

gotta remember they were building cheap consumer goods, a 'workin' mans tool' not museum pieces, a couple minutes or pennies saved per truck added up to a profit

Bill

Never been repainted; still has the original assembly line marks on the firewall. We have documentation on this truck like you wouldn't believe.

The black primer is good to know. That's what we'll go with. FYI, the inside of the doors have redish brown primer.

Thanks for the reply, I am getting the information I had hoped I would.

More on the primer colour, on the cab the primer is red, yet on the box and fenders it's black.

I know that it has never been repainted or even in a body shop until we pulled it out of the bush. So it seems that there really aren't any steadfast rules to follow. Makes it easier, in one sense.

note that the sheet metal bits were made, primed, even painted, at different places [including different plants] than where the final truck was assembled .... possible some of your truck was actually sourced from the US and some from Ontario

Bill

I was looking at the photos of your 1957, seems like you have completed what I am starting. Would you mind sending me some more detailed photos of that truck? They will probably answer a lot of my questions.

the Frankentruck is actually a combination of about 8 diffrent trucks, 56 US cab that had been reworked a couple times, with mostly 57 GMC sheet metal on a 58 CDN frame, with 56 - 58 driveline and a 60's bed, I was "saving history" from the scrap heap [and cleaning up the yard!] ... the pics there are most of what I have of that truck and I no longer have it, but there may be some of use on the "details" link below

Bill