The Stovebolt Site Forums Welcome! Welcome Centre Do It Yourself (DITY) Gallery 1947 2nd-Series GMC FC152 3/4-ton "Safe, Serviceable, Nice"

Although I have worked on many Chevys of this vintage, this is my first pre-'73 GMC. "Ol' Bess" was named by the previous owner in Idyllwild, CA, driven for about 6 or 7 years, then parked for the last 14 or 15 years. She just arrived in North Carolina last week via transport. (For those of you who may remember me as a Texas member, I relocated to the NC coast last year.)

Ol' Bess originated in Wisconsin, where she must have sat for many years. She's solid, mostly rust free, non-running, no service brakes (thankfully, the parking brake works), and a wiring harness that is beyond its useful life (prime reason she's not currently running). She has many bumps and bruises and passenger door held shut with a leather thong. There is no tailgate but there is channel welded on the box that must have held a couple boards slid in to serve as a make-shift tailgate. What a great project!

The plan is not to fully restore but to make a safe, serviceable, nice truck that appears stock. It will be a fun driver for trips to the garden and hardware stores, and perhaps some cruising. Maybe some light restoration will make sense, such as adding a correct tailgate. We shall see!

The PCV system is unusual, but not unheard of, on a smaller GMC truck of this era. The PCV valve can be disassembled, cleaned and put back in service.

Looks like someone downgraded the carb.

Nice truck. I remember that truck from around here several years ago. Congrats on your jump into the deep end. You will have fun with that one. I gather a wiring harness is first on the list? Having just undertaken the very same project I can say that it's easiest to pull the gauge clusters and get them done now and put them back at the same time with the new wiring harness. Keep us all posted on your progress.

That's pretty cool dr doug. I received a truck in similar condition 3 years ago after it had been sitting for 5 years not being started. I've since brought it back to daily use service with no plans to do anything about the body.

New fuel tank, fuel line, and rebuilt carburetor were first on the list. Then brakes, wheels and tires, and rewired headlights.

Basically I've tried to keep driving it while I've made the repairs.

That truck looks like it will be pretty easy to make roadworthy.

Thanks, Otto, "Twin," and Bill!

Yes, I was pleasantly surprised to see the somewhat unusual PCV system intact.

Wiring the engine compartment is the first priority, since the harness is in terrible shape (full replacement of the wiring will wait until I assess the running condition of the engine). I'm unsure about staying with the 6V positive ground system or converting to 12V negative ground since I want to use the truck as a local driver. If I were worried about originality, I would stay with the 6V system, as I have with my '53 Chevy. Pros and cons, as usual. I do intend to stay relatively stock overall, but for safety items (e.g., brakes), etc.

Here's a bit more info as I am surveying the state of affairs, so to say.

Fuel-system: the plan is to replace the Rochester B with a Carter 574S that I picked up, while looking for a proper Zenith 228AV11. I need to drop the under-bed tank and see if it is serviceable. The filler neck is missing (photo), so the tank is wide open at present (well, plugged with a rag). For now, I will get running with a portable marine tank that I use for that purpose. Is the filler neck for the 47-'48 3/4 ton unique? I've not located a replacement listed for this truck, so I need to look for alternatives, it seems.

Brakes: the right rear wheel cylinder is leaking, so there is no pedal at the moment. I've read the Tech Tip on the Eaton HO50/52 carrier swap that includes some info on brake conversion. I've also seen some of the disk brake conversion kits that may be a practical way to move away from the Huck brakes. I need to research options more before deciding a course of action.

Wheels/tires: the wheels currently mounted are later model 16" with General radials. I have a full set of 15" split wheels that came with the truck. But I'm a bit confused about whether they would have been original to the truck. Looking at the '47 Chevy VIK from the GM Heritage Center archives, it looks like the equivalent (5800 lb GVWR) 3600 would have been fitted with 17" wheels. I'm also uncertain if the 15" wheels would clear later brakes (e.g., '68-'72 as referenced in the HO52 Tech Tip). More research to do.

Rust: fortunately, fairly minor from what I've seen so far. There is a small area that should be patched in the bed, but it's in a flat side panel, so no real challenge. The other two areas that need sheet metal patches are best seen in the cab, where the floor meets the inner side panels (both sides, see photos).

Glass: the driver's side windshield is partially fogged, and the driver's window is badly cracked. A quick check with the usual sources shows a complete kit with seals to be reasonably affordable. Uncertain whether I will go non-stock with green or gray tinted windows or stay stock with clear glass.

Which brings me to the slippery slope of project scope creep. When I first saw the truck last February, I thought the paint looked like sun-faded Pimpernel Scarlet. In fact, it's an orange repaint, with signs of blue paint underneath (photo). The firewall suggests the original color was probably Pimpernel Scarlet, but I need to do more forensics to see if that's correct. So why does the discussion of glass get me to paint color? I'm sure there is some rust removal that will be apparent once the windshield and rear glass are removed. Then how much do I paint? And what color?

Fun stuff: over the years, there have been some minor "customizations" that give me a chuckle. The fan belt must have been replaced with a non-standard length at some point.
To get things to "fit," a second generator upper mount strap was added, and moved to a higher water pump bolt (fifth photo), resulting in a double-jointed mount. I think I will fix that.

One of the freeze plugs was replaced with an adapter and an electric temperature sender. That's all that remains. No signs of the gauge or wiring. But there is an aftermarket mechanical temperature gauge attached to the steering column with a wrapped and tied rag. Seriously!

I will post more as I find it as well as an update on the engine condition. Comments and suggestions are always welcome!

Doug

Hi DrDoug. That's a lot of stuff. I'll give you my opinions based on my own experience.

Anyway, here goes:

Fuel: If the tank is not rusted completely out, I would try to clean it out and coat it with one of the DIY sloshing compounds. I have done this twice and both tanks lasted decades. One had a couple pinhole leaks and the other had some surface rust inside. I think I used the Eastwood product buyt I can't recall. Each tank lasted 20-25 years. In each case, new tanks weren't being made at the time.

Don't neglect the fuel lines themselves. They could be rusted up on the inside or full of crap. Inline Tube might make a pre-bent line for your truck. I've used them on my truck and Cadillac and they are perfect in all respects and fit like they should. Much less work than forming your own fuel line.

Electrical: Switch the + and - on the battery and you won't have any trouble. Be sure to switch the + and - wires on the coil as well. Wire to the points should be same as ground. I'm pretty sure nothing on the dashboard cares which way the electrons flow. If I'm wrong, I'll soon be called out.

Edit: He was. See Rich's post here just added a few clicks down this thread. ~ Peggy M

There is nothing wrong with a 6v system. I use my truck a s regular transportation and I have never had any electyrical problemss that have anything to do with 6 or 12 volts. The key to 6v systems is to make sure your battery cables are 00 gauge and that all your ground cables and ground connections are clean and tight. My starter spins over as fast as any modern 12v car.

My 6v sealed beam halogen headlights are as bright and shine as far as any 12v vehicle I own.

Don't switch to 12v out of fear. Switch if you plan on adding a bunch of modern electrical stuff.

My truck, Cadillacs, and Galaxie 500 all have DC generators and they do the job just fine. No need to "upgrade" to an AC generator (alternator).

My philosophy is/was to use what I have and not try to reinvent the wheel. If your truck were already gutted and you were starting from a blank slate, by all means install 12v w/alternator.

Glass: My windows are all bubbly in the corners and edges. I have no plans to replace any of the glass.

Wheels: I have 16" General tires on my Packard. Those are awesome tires. I had 16" wheels made for my truck to get rid of the horrible 15" trailer wheels that were on my truck 3 years ago. They look great. The larger diameter wheels and tires look a lot better under the fat fenders and also allow you to drive a little faster on the highway without excessively revving the engine.

Brakes: My truck has Huck brakes all the way around. I installed new wheel cylinders, shoes, and master cylinder and have been driving for thousands of miles without issue. There is nothing really wrong with the Huck Brake design. It's just different.



My goal was and is to drive the truck, not work on it. If the parts that are on it are serviceable or if the system in question is generally sound, I see no reason to "upgrade" it. It's a lot faster and easier to replace or repair parts and systems with stock components.

I also like to be able to look at the shop manual to see how things are supposed to be. I don't presume to be more knowledgeable than the engineers who designed the vehicle so whatever they say goes.

Just to add a hearty Harrumph to what Otto just said. As loathe as I may be to agree with him on just about anything good conscience and form compels me in this case (tell no one!)

Like Otto, my goal with my trucks is to drive them rather than work on them. I, too, drive a truck regularly on 6 volts, bias plys, Huck brakes, manual steering, gas tank in the cab, blah blah blah and yet here I am -- still alive! I even enjoy a cigar now and then whilst driving my truck (and being in the cab with the gas tank ... )

Remember, you can throw a bunch of money at the truck and all kinds of upgrades. But what's the point? What's your reason for being here? Is it to have the "old truck experience" as Otto and I (and many others) do? Or something else? I am not passing judgement, I am merely seconding Otto in absolving you of any requirement to upgrade if that's not your passion.

The truck in its original form as the GM engineers designed it is still as valid today as when they designed it. Maybe a little slower ... and not as friendly to modern conveniences (WiFi/Bluetooth??? HAHAHAHAHAHAHAHAHA )

Many of us do a few changes here and there, but that's because we *choose* to, not because we feel the need to.



Sorry if I went off -- I just liked Otto's response (again, tell no one!) and thought I should foot stomp it.



Carry on!

Not deliberately intending to call anyone out, but I THINK you'll need to reverse the wires on the ammeter, or else it will show a discharge instead of a charge. Everything else should be OK.

Yes, I think that's right.I knew I forgot something.

Doug, I think this reproduction 1947-48 fuel filler neck may be just what you need to resolve the missing part predicament. Others with more knowledge will surely chime in and acknowledge or correct my info. Your truck looks great!

Thanks, Dan. I saw that part, but I was confused about its fitment. The product listing title and the description state for 1/2 ton. But the longer fitment list for the product includes 3/4 & 1-ton models. So, I have sent Classic an email clarifying fitment. Hopefully it works!

Thanks, again, and thanks for the kind words!

Doug

Doug, Just a further thought. If it's the same style/diameter filler neck, which would attach to the tank neck with a coupler hose, but the length wasn't long enough you could compensate with a longer length coupler hose to marry them up. Maybe??? Will be interested to see what Classic has to say.

Below from 1939-53 GMC Master Parts Book. Looks like the 47-8 UPPER pipe is the same for 1/2 and 3/4 ton pickups, but the LOWER pipe is different.

Otto, John & Rich.

Thanks for all the input.

I guess when I wrote my description of my initial surveying of the truck's status, I wasn't too clear that I was "thinking out loud" about options, and not clear on my goals. I agree with what was said!

With regard to wheels, I was thinking about going from the later-model 16" wheels that are on the truck to what may be a more original 17" size given the truck's GVWR. Uncertain I will make any change.

With regard to 6V systems, I really have no concerns. As I wrote, my '53 Chevy still has its OE 6V system/components and runs/starts fine. But with a complete rewire needed for this truck, I am considering possible alternatives, that's all. FWIW, I've had good service from the NAPA "commercial" 6V battery (P/N 7244), which is made by East Penn industries, and is a store-branded DEKA P/N 901MF.

In addition to paying close attention to cleanliness of connections and adequately sized battery cable & ground strap(s), there are sometimes some helpful updates which can be found studying the later, overlapping-year Master Parts catalog/books. For example, on my '53, I run a '54 6V starter that I believe Chevy introduced for Powerglide cars to address customer complaints of slow cranking, Delco 1108035. It's a 4-field-coil starter vs the 2-field-coil units used on standard transmission cars and all prior to '54. Only problem is finding them for a reasonable price, since the '54 Corvettes used that starter, too. Anyway, I have 6V generator/regulators, a somewhat later 12V generator/regulator, and 3-wire 10SI alternators available. That's part of my indecision on which way to go. No shortage of parts in that regard.

Back to the subject at hand, I have research to do (well beyond the electrical system), including parts interchange with Chevy. I've already picked up a GMC shop manual reprint that covers '47-'50 light truck models and I'm pursuing a copy of the '39-'54 GMC master parts book. I have a good library of Chevy manuals of various vintage (Carter and some Stromberg, too), and I'm a fan of using the factory info to the max extent possible. Just now building my GMC resources (including connections in this Forum, of course)!

Thanks, again, all.

Doug

Bill & Dan,

Thanks for the additional info and thoughts. Classic lists the "matching" fuel filler hose and does show different parts for the 1/2 and 3/4-ton. I'm not seeing a "lower" filler neck, other than the connecting hose, so maybe that's what is different, in which case, all should be good with the "upper" from Classic. I will post what they say.

Otto, I meant to mention in my earlier post, I have used Caswell's gas tank sealer which works well. I believe the Eastwood stuff is similar and possibly the same. Thanks.

Doug

Doug: One of the 'Bolters here sells a .PDF file of the 39-53 GMC Master Parts Book. That is where I got the info I posted above.

The guy's name is Andy. His handle on this web site is SlimSix. His email address is [email protected]

Bill, hope you don't mind if I added a PS to your post here. I didn't want to get Doug's DITY any off kilter but wanted him to know a little about Andy.

Andy was also a huge help to Kathy Weeks in Barry's Memorial. (See the Passing Lane entries.) Andy is a great guy. ~ Peggy

Thanks, Bill.

Thanks, Peggy.

Short update: other priorities have kept me from making much progress over the past two months, but I continue to survey the truck's current condition, and I have started to accumulate parts that I will need to address first various safety-related items.

Regarding the upper fuel filler pipe, the original piece was under the extra wheels in the bed. I suspect the transport guys tossed it there. Why they wouldn't have put it in the cab, I have no idea. To close out the earlier discussion, the folks at Classic finally answered my question, but did not clarify fitment. Based on the Master Parts Book entry, I do believe the piece is the same for '47-'48 FC100 and FC150 models. Thanks, Bill.

I've found two areas of rust-through, neither of which is too extensive. Both areas are where the cab floor meets the side panel - both passenger and driver's side - and neither looks to be too tough to repair with new metal patch pieces (see photos). The doors are in good shape. The seat could use some TLC but is serviceable.