The Stovebolt Site Forums The Shop Area Paint and Body Shop GMC 1948 Pickup Rebuild

Hello All,

Allow me to move into the paint department with my GMC 48 rebuilding job to ask some general questions.

I am use to learning new things, doing it for 72 years and I am not tired of learning.

Several questions bug & bother me:

A) getting rust, old paint off is easiest done with blasting. The division comes on 'for what item' ? So, sandblasting with fine sand for the frame and powder coat that black? My son has it done for the frame of his 1986 Buick station wagon and he seems to be happy with it, but that was done by a sand blasting shop since our booth can't handle the full frame.

B) How about other pieces? We can powder coat up to 8'x4'x3' pieces, so would it make sense to powder coat as much as possible?

C) Can one powder coat all metal pieces or is there a true advantage by going with spray paint?

I have painted a lot over my years, but never car parts, cause they scare me, truly!

So, give me your help, please!

Joerg

What are you talking about specifically?

I used Rust-Oleum rattle cans on the frame and undercarriage of my Cadillac over 20 years ago. I use the vehicle as my primary transportation and is still looks like new.

I rattle canned the side cover, engine cover and draft tube on Ol' Roy's engine and the rest of my vehicles. It's durable and lasts a long time. If you can powder coat it, go for it but It's not necessary.

Thanks, Otto. I have 'rattle canned' a lot, but never considered it being a true paint job, 😁.

Whatabout fenders, hood, cab, doors inside & out? Rattle can it all? My trigger fingers might be done when I am done, then I am done!

Ya, I've never done that but know people who have. It can give a decent result but I wouldn't do it on a restoration project.

Regardless of paint and method used, the single most important factor in achieving beautiful, lasting finish is the preparation. That goes for auto parts, bodywork, houses, furniture, etc.

I painted my house and the finish was smooth as glass and no peeling or flaking after 11 years. I spent a lot of time grinding the 90 years of paint off of it down to the bare wood. Sanded, prepped, cleaned, etc before a single coat of oil based primer went on. Then let that dry for a week before 2 coats of acrylic latex went on. I applied it with a brush, not a paint sprayer.

My point is that you can achieve perfection with whatever method you choose, just make sure the bodywork is perfectly straight, perfectly smooth, and hermetically clean before applying the primer and finish.

Simple question: do I need a shop manual for my 1948 GMC rebuild or will my Chev. shop manual 1948-53 do?

How much difference is between them?

Re: Powder coating vs. conventional paint.
Powder coating requires heating (as you probably know), so it's a two step process. One disadvantage of powder coating it that if rust gets under it (chip or whatever), it can grow under the coating and it will peel off in sheets. Conventional paint (epoxy primer, filler primer and topcoat) can be repaired more easily than powder coating. Conventional paint system gives you a chance to correct small defects in the surface before you topcoat. I'm not sure that powder coating could even be applied on a part that has a little filler on it. I wouldn't recommend powder coating on body panels.
re: Rattle cans
Most have less than optimal spray pattern versus an air powered paint gun (even the cheapest Harbor Freight gun) and what happens when the can runs out of propellant 1/2 way thru a panel and you have to go buy another one. And when a rattle can starts to lose pressure, they'll start spitting big globs of paint instead of a nicely atomized spray. Rattle cans are fine for small items I have used them for various parts, like the brackets for my oil filter mounting, the oil filter canister itself and for touch up of spots on the frame, which I sprayed with epoxy primer and Rustoleum Industrial Enamel in quart cans.

I bought a 3M Accuspray paint gun with disposable nozzles and paint cups, which make gun cleanup very easy. A gun and starter kit is available on AMAZON It was just over $200 when I bought mine. It does a good job.

The answer is "It depends"

In USA manufactured trucks, the differences are primarily engine and electrical grounding.

Is your GMC a Canadian manufacturered truck? If so, it left the factory with a Chevy engine and I assume (there's that word) a negative ground electrial system. If your GMC was made in the USA, it had a completely different GMC engine and a positive ground electrical system. Most other parts are interchangable.

I think I get the 'drift' out of what you all have said and it comes into my direction of thought.

The book I will order and see what I can learn from it. Interestingly, I was brought-up by a father who requested the parts book when he ordered a new machine, tractor etc. and I recall one instance when the seller (in does olden-days, the owner of the company) sent the manual. My dad went ballistic and told the good man 'how can I know how the parts in the machine work together if I don't know how they are put together' and that is exactly true. Well, today nobody once you to know how everything works together, cause people without knowledge are easier to herd.

Powder-coating struck me the first time my oldest had everything build for our oven and put charge to a build piece of steel, sand blasted and clean as can be, washed and 'gased-off', stuck the primer powder on & backed it, pulled it out and sprayed the actual color on, backed it again, pulled it out and clear coated it and backed again and after letting it cool the part went into whatever it was made for. No day to wait for it to dry or the scare to touch it to put finger marks on.

But I get your drift (again) and will do it for the frame, because once sandblasted (with low pressure and fine grid sand) the whole frame can be nicely done. Some structural parts we will do ourselves (powder coat) the rest will be sprayed. My son has what Kevin mentioned, a 3M accuspray. Not sure if he let's me use it, I doubt it, but I have seen the advantage of the system, particularly for smaller amounts to be sprayed and will invest in one myself to get this right.

LOTS to LEARN, AGAIN.

Joerg - I see you've identified your '48 GMC in your signature line as a "Model 9434", a Canadian GM produced truck. For Shop Manuals to support your truck, you'll need both the 1947 Chevrolet and GMC Trucks Maintenance Manual, like this one currently offered on ebay located in Nanoose Bay, British Columbia, Canada. Plus a 1948-50 Chevrolet and GMC Trucks Maintenance Manual Supplement to 1947 Manual offered by Faxon Auto Literature in Riverside California.

The 1947 manual is the basic complete Maintenance Manual. The 1948-50 Supplement to the 1947 Manual covers only changes from the 1947 model year, so not a complete book by itself.

I actually own a set of both of these manuals in my personal "Stovebolt Library", so if you need some help or specific information for your '48 before you can acquire your own books, send me a PM and I'll be glad to try and capture and provide you with pictures of the manual sections you may need.

sweet, Dan, I will get at them right away! You guys are the best

Ordered the books, thanks!

Well, I am slowly moving ahead.

Both front fenders off, need my helper for the front part to get the bolts out.

No idea why the put 1" or 1 1/2" bolts in where 1/2" or max. 3/4" would be long enough. I guess the builders didn't think much of me having to run 3/4 rusted thread through a nut where one needs specialty wrenches to get in and hold the opposing side of the connection.

The joys of rusty fasteners.

My method for removing rusty fasteners is to tighten them till they snap.

The easiest way to remove the front fenders, rather than individually, is to unbolt them from the cab and pull the whole front clip in one piece. But it looks like you got it done.

Me again. You all will know what goes on in my head right now. I am ripping my old truck apart, but I am laying in bed and think about 'how & what' to do with the pieces.

I believe I have a very good plan, but, plans are there to be re-drawn. Others have the option to abandon what they started, I have never done it.

My oldest and I had the discussion on this truck some years ago and it went like this: me, I like to keep it stock as much as possible. He, f.... that noise, V8, turbo, inter-cooled, I got the parts, front axle, rear-axle, tranie, frame, just keep the cab & box. Me, no chance, original as much as possible. End of conversation.

Now I start thinking about the engine, the old L6 run when we started the dismantling. No problem to rebuild it to 'as-good-as-new' condition, but than I have my 261 Pontiac with 848 head with a good HP potential. We can make that relatively easily fit and I have nearly double the original pony's.

But than comes - what goes fast (relatively) forward needs to be stopped some how and I think of the TSM Mfg. Kit #1847 front disk break conversion kit. That's were my son starts loving 'you are not original anymore' and he has a point.

What do do?

Jorg , all of my vehicles are virtually 100% stock. I have been driving my 1956 Coupe DeVille as my primary vehicle for 25 years. It has excellent drum brakes will cruise at 80 miles an hour for 9 hours straight without breaking a sweat on its original engine that has never been rebuilt.

I use the 1950 Chevrolet pickup for work and regularly drive 55 to 65 mph on interstate traffic, and in stop and go rush hour traffic on the freeway. It also has properly rebuilt stock Huck brakes. The engine itself has never been rebuilt as far as I know. At least not in the last 30 years.

Four wheel drum brakes when properly adjusted and kept in good order work perfectly with no drama. Why do you think tractor trailers , dump trucks, and box trucks, etc all use drum brakes?

How fast do you want to drive in an antique truck? If you put a V8 in it are you really going to be driving 80 or 90 miles an hour? I doubt it.

I'm a firm believer in not trying to reinvent the wheel with my vehicles. The engineers that designed them knew what they were doing and they function perfectly when properly maintained.

All of my vehicles with the exception of the modern (post 1972) Ford trucks, have breaker point ignition, single brake reservoirs, and drum brakes.. I have never been worried or afraid of driving any of my vehicles in modern traffic on any type of road.

I understand the limitations of each vehicle and I don't attempt to drive beyond their limitations.

I vote for keeping it stock. One advantage to that is that if something breaks, you have a shop manual right in front of you that tells you exactly how to fix it.

Otto 😥 you saved me from going 🤪 thank you, I am back on the ground now.

Question: I recall we did the brakes many years ago, new hard lines, new master brake assembly and new wheel cylinders, but kept the shoes, just cleaned them up. The drums went on our lathe and we cut the grooves out, but I have to measure how much we cut, remembering that we had a discussion on it here and we did it very careful. The question is - can one get new brake drums for this truck?

If they're the same as the Chevrolet 3100, I'm pretty sure the filling station or Jim Carter or somebody sells them

👍

Jeorg - Just a note that the forum your post is in is currently is the "Paint and Body Shop". Not trying to slow you down, but please post questions or topics in the correct forum for the topic. That way the specific thing you want to discuss (brakes, engine, etc.) can get the attention and help it needs without wandering all over the whole truck spectrum.

You will get better "on-topic" advice and help by splitting these up into the distinct categories each section applies to. For general conversations on the truck overall, you can certainly bring those up in your DITY post. Just remember in there, it's more about the story of your project, including the decisions you make, but again technical questions should be posted for help in the on-topic Tech forums.