The Stovebolt Site Forums Project Journals Archived Journals 1951 GMC 1 ton - Improve-Drive-Improve-Drive... & Repeat -

EDIT
Pardon the broken picture links.
Try this album:
https://goo.gl/photos/H26qPfBHb7eS15698


Hello fellow Stovebolters,

This Journal will detail my work, thoughts, and methods while fixing up and playing with a 1 ton AD truck.

The broad plan is to fix what needs fixing, drive it, make some improvements/modifications, drive it and continue to fix/improve/drive and so on until it's mostly all driving. Not looking to do a frame off restoration or anything that would take the truck off the road for an extended period of time.

Brief background --

In 1999 I started driving a 1952 Chevy 1-ton pickup and came to really like these old trucks and the 1-ton pickups in particular. Learned a lot in the process of racking up many thousands of miles in that old truck.

However, the cab was quite rusty and because of previous "repairs" was not a good candidate for further repair. It was bad enough in 2006 that I took the truck off the road with long term plans of finding a good cab or an altogether better 1-ton pickup.

Fast forward to 2015. I realize that if I'm ever going to find and buy a nice 1-ton I need to actually search for and buy a good one.

Next post will cover my thoughts and methods for finding one.

Grigg

Ideally I wanted a complete running driving truck with zero or hardly any rust at all and a presentable useable paint job, the more original the better. Having worked for a good spell in a restoration shop and dealt with and replaced plenty of rusty sheet metal I fully understand the money, time, and frustration saved by starting with as solid a vehicle as you can possibly find and then afford (in that order).

What sort of truck?
Well it had to be 1948-1953, I don't care as much for the 54. Had to be a 1 ton, ideally a pickup bed. However a dually or flat bed would work and I'd swap on my old 52 Chevy bed.
GMC was first choice because I like the looks, I've never had one, and they have slightly better engines and a few other things. Chevy would also be a fine option.

Model year preferences? http://www.stovebolt.com/techtips/i...ign/Advance%20Design%20Spotting%20Guide/
First choice 1949 or 50 because of improved rear cab mounts, in cab fuel tank, and no vent windows. Personal preference on the windows but I think the later style cab mounts are a smart choice for the life of the cab, and in cab fuel tank is nice and convenient place to put one.
Second choice 1948, again no vent windows. later cab mounts can be added reasonably easy, outside fuel tank is not terrible.
Third choice 1952, has vent windows but also the better push button door handles. 1951 hood emblems look better than.. 1953 which does have push button door handles.
Really any of the others would be fine for lack of a 49 or 50.

How and were to search?
Posted a wanted ad here on the Stovebolt forum as well as on the www.oldgmctrucks.com forum.
Searched ebay for both GMC and Chevrolet narrowed by years 48-53.
Searched all of craigslist with www.adhuntr.com with the search terms: GMC 1948 OR 1949 OR 1950 OR 1951 OR 1952 OR 1953 OR 48 OR 49.... and so on. Using "OR" between terms lets it return results for GMC and all the included years at once. This avoids making lots of single searches for every year, and yet a different search for "1948" and "48". Also weeds out duplicate results had it been lots of single searches. Similar broad searches were made for Chevy, Chevrolet, 3800, 250 and so on.

This process after a few weeks and months also gives some idea what the trucks are selling for and what a fair asking price is.
In general I found ebay trucks to be priced pretty high, and quite hard to judge value without seeing the truck in person. My best chance on ebay was for an interesting truck to not sell so I could later inspect it in person, or do so before the auction ended if close by. I did not look at any ebay trucks in person though I was first in line and ready to travel to see one in IL had the high bidder backed out, which he didn't.

The craigslist leads were more fruitful and provided several trucks to look at.
That story and the 5,700 mile roadtrip in the next post.

Grigg

The trip.
The Timber Framers Guild had a conference scheduled in Coeur d'Alene, ID that I was attending. I was also in need of a good road trip and decided to drive which opened up the better part of the country to my truck search. I was seriously considering driving a suitable truck home if I found it, having done similar feats before and had fun.
This trip shaped up differently when a friend who recently moved to Denver asked if I could help bring his 48 GMC 1/2 ton project and pieces out to him. With the better portion of the fuel cost covered for the entire trip I didn't mind driving a truck and dragging a trailer instead of riding in comfort in the car sipping fuel.

Here's an overview map of the trip
https://picasaweb.google.com/lh/photo/Zf3VSH4e_XRdB5fdLkSkptMTjNZETYmyPJy0liipFm0?feat=directlink
Starting in Virginia and headed straight west to Denver. Returning by the northern rout with a dip down to Asheville, NC.

My "Good" friend Adam signed up for the trip and the TFG conference under the assumption that Idaho was somewhere out there with Illinois and Iowa. Not long before departure and already to late to back out Adam's brother pointed out the error and showed him a map...
This reminds me of a delightful toast about road trips, among other fine things, presented by Adam and my other BM's.
https://flanamullegan.wordpress.com/2013/05/26/youre-on-a-road-trip-with-grigg-a-toast/

Using Craigslist as our travel adviser we picked a rout, collected some notes and phone numbers for trucks to look at, a junkyard to browse, and some new scenery to take in.
We left about 8:00 in the morning Monday and made it to Denver Tuesday shortly after dark. Unloaded the 48 project and turned in for a shower and a good nights sleep.
Below are several pictures from our travels and junkyard browsing on the way to Denver.

Museum in Russell, KS on the way
https://picasaweb.google.com/lh/photo/DiwVuw1T5sZNRCcbsZKX5tMTjNZETYmyPJy0liipFm0?feat=directlink
GMC with 4-71 Diesel
https://picasaweb.google.com/lh/photo/KQb4U1EQi_BGG25ZRMTyx9MTjNZETYmyPJy0liipFm0?feat=directlink
Several more old GM trucks, none as nice as I was looking for but certianly plenty of good parts, much better than what we have at home.
https://picasaweb.google.com/lh/photo/7Z5XM0LZKOaAZM7Lk3BM_9MTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/7cPn4mCIbQoN85_IVH1LpdMTjNZETYmyPJy0liipFm0?feat=directlink
https://lh3.googleusercontent.com/-...AAIEM/OHBl9Bon8A4/s912-Ic42/IMG_0228.JPG
https://picasaweb.google.com/lh/photo/G2PbOGfTtsC6dxzGzvpp89MTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/FvzcG959S9VN1ofZyVEXNNMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/aW6d---8ZKxACTO_tH__DNMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/NRG0tslKmZcXkPFxL-8xIdMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/-NyNoCR0Ra3YXLmiMWInxdMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/2z_ALDiW8Szdg3yfzZNH6tMTjNZETYmyPJy0liipFm0?feat=directlink

Next leg of the trip and further truck hunting to follow.

Grigg

Leaving Denver Wednesday morning we almost headed North to Wyoming.
In Wyoming was a GMC 1 ton cab and chassis without title but running and driving. The truck was cheap, perhaps too cheap, looked OK in the pictures, and may or may not have been rusty as I couldn't get a lot of detail over the phone. Upon further thought we decided not to go look, it was somewhat inconvenient to get to and I was sure it'd be more project that I really wanted. The cheap price probably couldn't offset the amount of work it would surly need to equal the completeness and quality of the truck I was really searching for.

Instead of going North we turned West on I-70 as Adam hadn't yet seen the big mountains out there and it'd make for a nice drive, we even found some snow. In Rifle Colorado we got off the highway and headed more or less straight for Salt Lake city on some nice smaller roads. For this stretch of the trip from Denver to ID, about 1,200 miles, without a load we had removed the two front tires on the trailer and chained the axle up. This helped the trailer ride better, less wear on tires, and got the fuel mileage up to just over 15 MPG.

Thursday morning we found ourselves in Horseshoe Bend north of Boise, ID at an excellent breakfast spot called the Long Branch Saloon. I'd never been to a saloon for breakfast... before the sun even came up they were open and we were hungry, right place right time.

Driving North through Idaho provides great scenery and in an hour or two it's completely different, and different yet an hour or so after that; all great and interesting. I'd like to make that drive again some day; in my estimation it was the most enjoyable stretch of our entire trip.

Around lunch time we stopped to look at one of the more promising trucks I had found. It was not cheap, apparently had some wiggle room on the price, looked clean and straight in the pictures, and the seller was a good and pleasant guy. An original Chevy 9' pickup with a 12-15 year old restoration, current owner hadn't had it long and needed to sell it.
Here are some pictures of it:
https://picasaweb.google.com/lh/photo/B9RQK2IjcpjoLRJHR0UKe9MTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/AZdT_1b4DnxoszmDPytYVdMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/bWI3PJEwnav3BEh3x4c6gNMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/1hh-W3hlS-nivpaU9lmHVdMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/q9wYGhog5QvX_2d2sDozodMTjNZETYmyPJy0liipFm0?feat=directlink

It was very apparent before even looking close that this truck was not the one. It was much easier to find problems and troubles with, caused by, or overlooked in the "restoration" than it was to find anything exceptionally nice about it. May have been a nice looking useful truck back a few years ago but was quickly becoming a candidate for a full and proper restoration to prevent further deterioration. More project than I needed even before talking about the price; skipped that discussion altogether and bid our farewells.


Next post about the next truck,

Grigg

Grigg
Thanks for the play by play adventure update!
It shows how you really did your research and had standards to meet, for what you wanted.

Don

Finally arriving in Coeur d'Alene Thursday mid afternoon there was one more truck to look at before the conference started. This one I spotted on craigslist 9 months prior and agreed to take a look if it was still available come October when I'd be in the area.

It hadn't sold in the meantime.
The owner was not the original however the truck had been in his family from new. A 1951 GMC dual wheel 1 ton.
https://picasaweb.google.com/lh/photo/FDy7H2e7C7zujdeMKCLeYtMTjNZETYmyPJy0liipFm0?feat=directlink

Long story short it is a very clean truck, only major things against it was one spot of rust on the passengers floor and the bed I don't care a lot for. It has new glass in all except the rear, paint is presentable, frame looks good, brakes worked and had a few new flex lines and other recent work. Engine ran and sounded good, drove well, shifted smooth.
Not all perfect but these things I expect and or can deal with easily. Needs wiring harness soon, no shorts at present. Tires are old and checked but holding air, likely will last a while yet. Bed has rotten wood and some rust under a plywood floor. Original (I think) seat cover has some duct tape repairs. Wipers don't work. Carb requires part choke to run smooth.

We made a deal, loaded up the truck and strapped it down. For safe keeping over the weekend I backed truck, trailer, and pickup truck into the shop where the seller works. Walked the two blocks back to the conference center and supper quite pleased to have found a very decent 1 ton GMC.

https://picasaweb.google.com/lh/photo/5cPP7CYMbYdnx3iIl9KRLNMTjNZETYmyPJy0liipFm0?feat=directlink


Next the balance of the trip then preliminary work on the truck,

Grigg

Sunday evening about 6:30 or so east coast time we departed Coeur d'Alene, ID.
First stop was half hour later to pickup a small ice cream dipping cabinet/freezer. Also a craigslist find a few months ago that happened to still be there.

We took a somewhat Northern rout through Montana which would have been nice to see if it wasn't dark out...
Truck and trailer pulled well and soon enough we were in Minnesota where we stopped in Frazee Monday evening to pickup a single cylinder Detroit Diesel for a friend.

Here's a pic with the entire load.
https://picasaweb.google.com/lh/photo/5e191nzhG_1-kEqLzh-dP9MTjNZETYmyPJy0liipFm0?feat=directlink

A little about the towing truck.
My Father's 05 F250 he bought new with a 5.4L gas engine. Couple years ago we had a 1999 24V Cummins and an 07 model G56 manual transmission swapped into it. It performed quite well on the whole trip. Average fuel mileage while towing was about 13.5 and with empty trailer just over 15 MPG. We moved along at 65-75 depending on the road and conditions.
The 100 gallon transfer tank/tool box was borrowed from a neighbor for the trip. In addition to dry storage for our luggage the 100 gallons of fuel was real handy for buying cheap fuel where we could and using it while fuel was expensive at the pump. Also saved time and aggravation because we could pull off at a rest area and top off off the truck all in just a few minutes, no worries about finding a fuel station and navigating to it with trailer in tow in the wee hours of the morning. Increased our range by 4X.
The crew cab truck we had setup with a shelf in front of the back seat making room for a mattress so we could alternate driving and sleeping. On a couple occasions we pulled in a rest area and the other one of us would sleep on the front seat for a spell.
Some pictures of the truck conversion here:
https://picasaweb.google.com/118082...onversion?authuser=0&feat=directlink

From Minnesota we headed for Knoxville, TN where Adam's Sister and family live. There we found a splendid supper, warm showers, and comfy beds waiting. I don't care to drive I-75 from Lexington to Knoxville again if I can avoid it. No fun with the traffic and a load.

Wednesday morning we headed out for Asheville, NC to fetch my VW car from the mechanic. This while out of our way still saved 300 miles and better part of a day had I tried to fetch otherwise. Pointed directly home at last Adam drove the VW while I followed along with the truck. Worked out nicely that he could zip along and even fetched takeout lunch while slower but steady I caught up with him at a rest area for the meal.

Well, not quite directly home from Asheville because I realized we'd be close to one of my favorite newer truck junk yards in Roanoke, VA during business hours. (Otherwise I can't get there without taking vacation time from work.) Stopped for a quick browse and to pull an air compressor for a friends truck project.

Finally we made it home pretty much 3 days from leaving Idaho and 2,700 miles later. Total trip an indicated 5,700 miles 9.5 days door to door with 3 days of conference in the middle.

Tomorrow I'll try to get y'all up to speed on the 51 GMC; brake work, carb tinkering, and a few other things,

Grigg

Grigg,

I think your new project has a WW2 military G506 bed, most likely made by Budd. There were a few changes in the bed depending on wartime resource availability so making a relatively good ID of vintage is not too difficult. If you take some pictures I can help you out.

Cool saga, I bet it was difficult to pay attention at your conference.

Paul

Thanks for the info on the bed, I was guessing it was from a military trailer having seen similar ones.
From a G506 truck makes more sense. What little I read so far indicates the bed is from the 40's, need to scrape the paint off the tag and see what it reveals. (edit, did that, made in 1945) I'll get more pictures in time too.
Might be the original bed to the truck though it was previously used/surplus at the time.


The truck fits well in the garage and meets approval. PICTURE

On my lunch break the day after getting it home I made the rounds to the Insurance agent, DMV, and county office for all the necessary paperwork. After getting home from work I took it for a couple mile drive up the road to a neighbor/friends house. It was pretty weak on the hills but drove OK. While we were checking it out in his driveway I noticed some oil on the frame under the bed... looking closer it was brake fluid from a rusted through brake line to the rear axle. I drove carefully home and the brakes continued to work luckily enough.

Friday I was back at work until after lunch I found out a couple local stovebolters were headed to the junkyard. Same yard I had spoken for a set of 8 lug dual 19.5" wheels about a year prior and hadn't made the time to go fetch yet. Now with a truck that could actually use the wheels for it was the perfect time to get them before I missed out on the deal. Sorry I forgot the pictures but all 6 with 8R19.5 tires fit in the back of my VW station wagon. Made for a nice afternoon trip and good to see some Stovebolters.

Saturday morning a local Stovebolter stopped by to lend a hand with the brake line replacement. He also picked up a few pointers on making brake lines, the part of his own project next to tackle.
Saturday midday two more Stovebolters stopped by to check out the truck and lend a hand with brake bleeding and carburetor fiddling.

The apparent carburetor troubles I first suspected may be just a vacuum leak. To test I sprayed ether/starting fluid on all the gaskets and such while running. Had the engine rpm picked up it would indicate a leak, we couldn't find one.
Next some collective brain storming lead to checking the float level and the accelerator pump. The float level was off some.

It has a Zenith model 228 carburetor. Here are some useful links for that.
http://www.carbkitsource.com/carbs/tech/Zenith/Zenith%20Model%2028%20228.html
http://c779252.r52.cf2.rackcdn.com/zenith_28_identification.pdf
http://www.zenithfuelsystems.com/downdraft_228.htm
http://www.autotestsys.com/Zenith.htm

We found the accelerator pump has 3 positions/stroke lengths for different tuning and only one clip is to be used in one of those positions. The carb was assembled with two clips capturing the accelerator linkage on the pump rod, this we decided and later confirmed was incorrect.
Originally these carbs used a steel accelerator pump plunger with no rubber cup and therefore very little friction. The throttle/accelerator pump linkage pushes on a spring when accelerating and that spring more gradually pushes the plunger down, the connection is not rigid. Problem was the rubber pump cup (aftermarket rebuild kit) was so sticky in the bore the spring could not overcome it, the pump would not function at all. Which lead to someone's idea to put an extra clip on the pump rod linking it solidly, this causes bent linkage if you move the throttle too quickly.

After evaluating the one whole, two half carburetors, and a box of little parts we decided I'd be better off looking for a carb in better shape.

Not to let a poorly running engine keep us from a trip to the local brewery we 3 packed into the cab and took it out for the second voyage. The beverages were good and the company better. Some little backfires and stumbling on the hills made for an interesting but successful ride back home.


Next some necessary yet boring brake work,

Grigg

Grigg, I would have had a hard time leaving this GMC sitting there...


https://picasaweb.google.com/lh/photo/NRG0tslKmZcXkPFxL-8xIdMTjNZETYmyPJy0liipFm0?feat=directlink


Looks to be somewhat solid too..

Yes, that old GMC was nice to see and not a common one, however I didn't set out to bring home that much of a project. If I had any money, more time, and plenty of garage space there are a whole lot of trucks I'd love to have..

Back to work on the 51 GMC.
loading and unloading it form the trailer I noticed the left rear brake was dragging pretty hard and the first thing I did to the truck once home was pull that drum, inspect, and back off the shoes.
On our trip to DB mentioned above we noticed a slight smell of brakes and stopped to check them, a few warm drums but not hot, we kept driving the few more miles to home.
Time to really go through and adjust everything by the book.

First I thought if more than one warm drum it could be MC is not relieving pressure, not getting full return stroke.
That adjustment is covered in the manual here http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0508.htm
About 13/16" between pedal bar and the floor board. Mine was too tight and this adjustment solved the dragging brake problems.

Also wanted to inspect all the brakes just to see what I had. The rear drums come off after removing the wheels and two flat head screws. The shoes looked pretty new and thick and the drums clean, smooth, and no lip.
Drum PICTURE
Shoes PICTURE
Right rear wheel cylinder was wet, it was leaking but had not soaked the shoes. I pulled the pistons and cups out to inspect.
Wheel cyl. PICTURE
There was a small amount of crud and discoloration but no serious pits. Measured the bore and the piston and found about 0.007" clearance which is about double the suggested amount.
See manual here: http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0526.htm

At this point I figured nothing to lose by honing it and putting new cups in; the piston and spring were clean.
I realize it will be out of spec and honing only increases the clearance but I estimate the cup will take up the slack and won't give any trouble. Also on my mind are plans for a different rear axle and not wanting to spend a whole lot of money on these brakes that I don't need for very long.
I'm all for doing things right the first time and try to always think about safety. In this case I weighed those values with what I expect out of these brakes and the cost. Had I intended to keep this axle/brakes I would have had the cylinders stainless steel sleeved (I considered doing it myself, even looked up thin wall seamless SS tube ). New cylinders run about $80 plus or minus some at NAPA, sleeving should be cheaper. New 1-3/8" cups at NAPA are $2.16 each.

After searching and searching the shop for my wheel cylinder hone I gave up and bought one the next day, some day I'll have two...

This job was simple.
First remove the top brake shoe spring with a set of brake spring pliers, flop the shoes out but still attached.
Next put some rags under the wheel cylinder, pull the adjusters, push on a piston to pop the other out, catch the fluid and remove both pistons, cups, and spring.
Then with cylinder hone on cordless drill hone the cylinder just enough to mostly clean up. I used some diesel in a squirt bottle to lubricate and flush while honing, not sure if that is right nor not but seemed like a good idea and it worked well.
Finally wash out the bore with brake clean as well as the pistons and spring. Reassemble with new cups lubricated in brake fluid.

One last thing about that right rear brake before reassembling.
The parking brake cable is missing a support bracket where it enters the backing plate and has damaged the cable sheath causing the cable to stick.
PICTURE
While I order new parking brake cables I disconnected this one from the link inside so it won't cause the brake to drag. The other cable is in fine shape and works well on the left side.
Anyone purchased cables from Inline Tube? They list cables for the 1 ton as original or stainless for $75 or $85 each, which is a little strange as the front page shows $39 or $49 as general pricing and these cables seem pretty normal, not special. I have not yet called for details.


Now on to the front wheels/brakes.
To get to them the whole hub must be removed. I elected to just remove the hub cap, cotter key, and spindle nut; Then pull hub, drum, wheel, and tire all together. This is faster and simple if you can be careful with the seal while doing it.
Front brakes looked similarly nice, good thickness on the shoes, clean drums with no lips, cylinders looked recent, no troubles at all. Even the ball wheel bearings looked like new (they may be?).

Here is the service manual on adjusting wheel bearings which is important to check because I'm more familiar with tapered roller bearings than I am ball bearings for this application.
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0307.htm (and the next page)
Torque to 33 ft lb and back off one flat (1/6th turn) and no more than 1.5 flats to fit cotter key.


Next post is master cylinder rebuild and brake adjusting,

Grigg

First a note on the service manual, a most invaluable tool for these old trucks.
The chevy manual is easily found online thanks to Keith Hardy. .
http://chevy.oldcarmanualproject.com/shop/1948_51truck/index.htm
The Chevy manual is a good reference even for the GMC because so much is the same between them.

I do like to have the right manual and found a used reprint of the correct GMC manual, you can buy a new one here from Jim Carter

I'm very impressed with the GMC manual, it goes into much more detail and covers more stuff than the Chevy manual does. For example recently there was a question about lubricating the brake cross shaft where it passes into the frame. The Chevy manual does not mention this in the lubrication section of the manual or in the brake section. The GMC manual does clearly explain in the lubrication section that it should be oiled every 1,000 miles with a squirt can of engine oil. Also noticed more detail on brake servicing, and I'm sure more good stuff throughout the GMC manual.
I recommend anyone with a Chevy should also get the GMC manual, I wish I had 16 years ago!

Grigg

OK, Master cylinder.
When adjusting the brake pedal I noticed the MC was leaking pretty good from the front end, from the bore/cup.
The MC looked pretty new so I decided to try just a kit for it, NAPA had the kit for $22, 1.25" bore.
Removed the MC, disassembled, and honed the bore just enough to mostly clean up, some discoloration is OK (to me), pits are not so good.
PICTURE

Referenced the shop manual and reassembled, reinstalled, checked pedal adjustment, adjusted all the brakes, and bleed them.

Details on adjusting the brakes.
Shop manual page http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0513.htm
The 51 1 ton has Huck brakes which have an adjuster on each end of the wheel cylinder, one for each shoe.
They get adjusted so the brakes just drag and then back off 5 clicks on the front and 4 flats of the hex on the rears. Some I may have adjusted more snug to start with and then needed a little more slack off so they wouldn't drag.

Now the brake pedal is very firm and the brakes work right close to the top, gives much more confidence than going half way to the floor before they work.
Having driven it and used them some they're getting seated and now the truck stops straight, before it pulled one way or the other. Still a little squeaky but that my go away, not sure.



Finally back to the carburetor troubles.
A friend offered to loan a new Zenith replacement carb if I'd fix a broken choke screw on it.
I was able to file the ends of the screw off, remove the shaft, drill the center of the screw, and as much as I don't like them... used a tiny "easy out" to remove the broken screw.
PICTURE

Next I needed to make a V flange sort of adapter ring so my air cleaner would clamp to this carb. I think such a ring comes with these carbs when sold as universal replacements, I didn't have one.
Turned one from a chunk of aluminum and slit it with the bandsaw, works just fine.
first PICTURE
second PICTURE

The new carb worked out just fine, started quick and ran smooth. Following the instructions I made some rough adjustments.
Carb adjustment instructions PICTURE


Next post, better part of a tuneup,

Grigg

Hi Grigg,

I ordered the exact cables you are looking for the for the 47 1-ton dually I'm working on from In-Line tube. Pretty good communication and they fit nicely at the drums. They are dangling now until I de-rust the frame, paint and prime. They look like they will attach nicely to the front cross bar across the frame. You will need to provide them some of your original hardware at the drum. Actually I think the piece you are missing, though that is junkyard common. If I had the chance I would do the SM-420 brake if I could. Best - Joe

Thanks for the info on the brake cables.

I'm looking at a 14 bolt rear axle swap and it has parking brakes at the wheel, looks like the original 1 ton brake cables will fit the newer axle/brakes. That will be simpler than also swapping a transmission parking brake, though those do work really well. Perhaps I could send them the hardware to reuse from the modern cables.

Tuneup,

First I wanted to adjust the valves and took a drive to get it warmed up for that.
The method i use was shown to me a long time ago and is simple enough to remember, no need to look it up every time.
Keep in mind that a 4 cycle engine with an even number of cylinders will have one piston up on the exhaust stroke when another cylinder/piston is also up but at compression. This is handy because the piston nearing TDC exhaust will be closing the exhaust valve and with just a little more rotation of the crank to TDC will open the intake valve.
It is real easy to watch for an exhaust valve closing and right after an intake valve opens. When this happens another cylinder is at TDC (or nearly so) of the compression stroke where both valves are very much closed and those lifters are well seated on the base circle of the cam, perfect place to adjust those two valves.

Simple/short version of the method is just figuring out which 2 cylinders move together, both at the top at the same time.
Write down the firing order (often cast on the intake manifold) in two columns, half on the left and then start the second column on the right.
firing order for a Stovebolt is 153624:
1 6
5 2
3 4
So when the valves/rocker arms just wiggle one after the other on cylinder #6 I can adjust cylinder #1. Rotate the engine a little more and valves will do their thing on #2 and I adjust #5. This can all be done within 2 rotations of the crankshaft.

PICTURE

I know by memory (from watching the engine turn over without head on) that the front and rear cylinders do the same thing, and the two center cylinders also do the same, which leaves # 2 and #5 doing their thing together, knowing that saves making the little chart.

The GMC service manual is vague on the valve lash. It suggest 0.012" intake and 0.020" exhaust at a starting point (cold after a rebuild?) and to look at a sticker on the valve cover for the values when warm. I don't have a sticker so went with 0.012" and 0.020" for now, better a little loose than too tight. They were all quite loose, they all needed adjusting.


Next points and timing,

Grigg

Distributor,
The points were pretty tight so I loosened them to about 0.019" gap which is within the range suggested by the shop manual.

Under the cap the rotor button had rubbed on one of the spark plug terminals and left some brass dust on the inside of the cap, washed that off to help prevent misfires.

Timing,
At first used the timing light to set the timing pointer not at the ball but perhaps 3/4" to the right of the ball; more advanced. Followed by a test drive up a steep hill across from the house listening for a ping or ignition knock. This setting seemed a little off, I forget which way but just not quite right...
Then I decided to try adjusting timing by ear listening for the most engine RPM at idle as this method had served me well in the past. I think it ended up with a little more advance than previously and after a test drive seemed to do OK, I'll leave it there for now.

I think the by ear and by test driving is better plan than the light until you figure out what works well. Then use the light to check and see what it is and put some paint on the flywheel so you can repeat that setting with the light. Remember that adjusting the points can change timing, so recheck/adjust after replacing them.

The ignition wires look OK but I should change the spark plugs before long, pulled one and it, although not eroded, had some carbon and stuff I assume more from running out of tune than from anything else. I may try to sand blast them but replacement might be simpler, I don't have a dedicated plug blasting/cleaning thing.
In fact before bringing this truck home I had been doing my best to do away with spark ignited engines and I'd consciously avoided purchasing tools specific to such engines. This had me asking for and borrowing a timing light last week too...


Next post on cab mounts,

Grigg

OK, driving along sounded like the cab was pretty solid on the frame... similar feeling to my old 3800 because the floor was so rotten the cab was sitting on the frame. Except the GMC has a very sound floor.
I looked under the front cab mounts and not a scrap of rubber left.

Curious what thickness rubber should be there I looked at what the restoration parts vendors sell and didn't find the answer listed, and no clear answer in my forum searching. Then I thought what about the manual, what does it say?
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0103.htm
It does not say what thickness rubber, better yet explains how much clearance should be between cab and frame bracket. Measuring my truck this equaled about 5/16" rubber.

The hardware for my mounts are in great shape, and removed quite easily. Nice working on something that isn't all rusty.

The round rubber washers on the bottom side were still there but extremely hard.

Picking through my collection of various rubber stuff found some new hay baler belt at 1/4" thick, perfect for those round washers. Found a scrap of a large conveyor belt from a quarry, it probably started out thick but had worn thinner in places. This was quite convenient because I could measure and pick where to cut the 2 square pieces from so they were just the thickness I needed.

PICTURE

Above picture shows the pieces. Cut the squares with a utility knife. Cut the round ones with an Allpax gasket cutter . A new old tool I had been searching for for years (new ones are pretty expensive). Finally found this one and it's about the handiest thing ever for cutting nice circular gaskets and washers; handy enough I should have bought one long ago.
The holes I drilled with a 9/16" paddle bit for wood with some little spurs on it, I had it and it worked. The thinner rubber I could have used a hole punch, but the thicker stuff was easier to drill. A brad point twist drill bit for wood is usually a good choice for rubber if you have such a thing, I didn't.

Then to install them used a little bottle jack and a piece of 2x4 under the very front corners of the cab, one corner at a time. Jack it up just enough to slip the new rubbers in. Then let it down and tighten the bolts just snug, not overly tight.

Replacing these cab mounts also improved the fit and function of the hood and the latch.


Next post, heater motor replacement,

Grigg

Grigg, very interesting insight on the fit and function of the hood and latch after installing new rubber. Great read. Thanks for sharing. Do the GM's have a Ranco valve setup and will you be getting into it ? I see several venders sell the rebuild "washer" and I am considering giving it try while I have a pile of parts in my hand. Happy Turkey - Joe

The Ranco heater valve/thermostat was an option on all these trucks same as just having a heater was an option. This truck didn't have one and I don't feel the need for one. My 52 I drove for years without one, just a valve on the water pump, on for winter and off in the summer. I do have one if I wanted to use it but for this truck plain and simple is the plan.
I've looked at rebuilding one and it looks pretty straightforward, just be careful bending those tabs.

Tomorrow I've borrowed a steam cleaner and hope to clean the drivetrain and another rear axle.
More updates later in the week,

Grigg

Sounds great. Keep that old axle, brakes and hubs close. I may have an interest.

Heater motor replacement.

The original heater didn't work so I traced some wires, tightened some connections and then it would run. However it wouldn't run very fast. Soon enough it blew the fuse in the heater switch.
Removed the heater to investigate.
PICTURE
Then removed motor and dissembled it just enough to see that the brushes were worn down to next to nothing, the commutator was very well worn, and lots of crud/dust/dirt inside. Seeing all that I quickly slid the motor back together and started looking for a replacement. If it was in better shape I would have oiled it and tried to keep it going.

Here's a thread in The Electrial Bay that goes into more detail on the motor.
https://www.stovebolt.com/ubbthread...eap_heater_blower_motor.html#Post1136055

I have the base model recirculating Harrison heater, it has a round heater core. I wanted a 12V motor.
Short answer is save your money, don't spend $45 + shipping online, instead go to NAPA (or likely other FLAPS) and order NAPA # 655-1022 for $33. (see alternate, cheaper!, part # for other heaters in the electrical thread linked above)
With motor in hand simple remove and replace, no modifications.

PICTURE 1
PICTURE 2
PICTURE 3

You may ask why I put a 12V motor in a 6V truck?
Because it'll still run (about half speed) and because in the future I'll do a 12V conversion. It works plenty good for now on 6V "full speed/hi"; the lower switch settings are too slow, don't use them.

Next post?? Changing fluids, considering rear axles, ordering seat belts... several things going on presently so more to come soon.

Grigg

So far I've covered the "improving" part and little of the "driving" part.

Early on we went for a couple little trips out with it running not so great and with brake problems.
A couple weeks ago after brake work, carb replacement, and valve adjusting finally seemed ready for a normal drive.
That Friday I drove it to work, lunch, errands after work, and back home. All without any troubles and with big smiles. Brought back memories of driving my old 52 anywhere I wanted whenever I wanted to.
It has been a long time now without a reliable useful old truck to drive around, or any truck for that matter. I sure missed it.

One weekend took it to the lumber store and picked up some 16' shelf boards for my wife's shop, that was fun. Later that day we attended a fancy dinner (fundraiser) in the old truck and picked up another friend on the way, also enjoyable.

It's been nice to drive an old AD truck again and I feel right at home behind the wheel! (I suppose to be proper it is a "New Design" truck being a GMC.)

Presently it's stuck in the garage having drained the rear axle and transmission. Trans I'll refill. Rear axle I plan to swap a 4.10 gear set in and that should firm up in the next week or so.

Grigg

Seatbelts part 1

Did a little research and found out that several of the common sources of seat belts get them from the same place, Made by Beam's.
Here http://www.seatbelts.net/distributors.php

Several years ago I ordered some 3pt ones from Juliano's for my 48, I have not used them yet.
http://www.seatbeltstore.com/

I think this is another separate manufacturer/assembler not related to Beam's (I wonder if they source some parts from same place??). I have no experience with them. http://www.seatbeltsplus.com/

The Beam's belts are/look to be good quality so I decided to stick with them. Now that I know where they really come from and can search better It seems Juliano's is somewhat more expensive than some of the other other distributors. Also found out that many of the distributors don't have a large selection or may have belts but zero or slim hardware options.

Andover Restraints has a very large selection of belts and mounting hardware to go with them.
Be warned though, the website is pretty lousy. However the customer service when calling so far has been great, no problem ordering over the phone and asking questions.
http://www.andoauto.com/

I found these two pages useful:
This one has retractable belts http://www.andoauto.com/AR5-1.htm
This one shows pictures of different hardware kits http://www.andoauto.com/kits.htm

In the past I've used non retractable belts and they're just fine. However if your passenger is not well educated in the matter they'll likely throw the belt at or out the door when exiting and then slam the door on it. This could be troublesome if you have nice paint and annoying even if you don't.
This time I decided to try retractable lap belts and ordered Andover part number 8244-20 Series with mounting kits # 204K. These have chrome lift type latch, an older looking buckle design.

I intend to mount the retractor behind and outside the seat frame just between gas tank and cab corner. The buckle end will go under the seat and come out between cushions.
This will be a project for the new year after the belts get here.


Next, who likes the smell of gear oil?

Grigg

last week I drained the transmission oil after removing the shifter stick and noticeing some condensation and brown sludge inside, no surprise as this is quite common. To remove shifter it's an easy press down and turn the collar counter clockwise a fraction of a turn with one hand.

Here is some of the sludge scraped out of the drain plug hole
PICTURE

It looked nasty enough that a flushing seemed like a good idea so I removed the fill plug on the transmission and reinstalled the drain plug for now. Then poured diesel fuel in the top until it ran out of the fill plug on the side of the transmission, replaced it, and put in another half quart or so. The idea is to fill it up but not so full it runs out the input shaft which may not have a seal (later models did).
Then I let it set for a few days.

Note. It is a whole heck of a lot easier to fill the transmission from the top than it is to squeeze or funnel anything into the fill port on the side, just use that to check the level.

A week or so prior I had removed rear axle cover and took pictures of the gears in preparation for trading it for some 4.10 gears. The trade is a go so this weekend I removed the differential "pumpkin" "center section" "chunk" or whatever you like to call it and packaged it for shipping.
PICTURE
Also removed the rear half of the driveshaft. Had I not already drained the rear end I could have left all that together and set the axle on jack stands to do this next part.

To help flush the transmission I wanted to run the engine and shift through the gears to get the diesel fuel in there stirred and splashed around. Without a load I don't think there is any danger of messing up bearings or bushings, diesel fuel is somewhat oily. All in all I ran it for about 10-15 minutes going through all the gears a few times while bringing the engine RPM up to normal driving speed. With that done I removed shifter again and looked inside, you can't really see much for gears or anything in there but what I could see looked much cleaner.
PICTURE
Finally I drained the diesel fuel and much of the sludge with it. Except the truck was parked just a little nose down and some dirt/sludge remained in the bottom, I should have jacked the front axle up significantly for this process. So I did jack it up and poured in another pint of fuel, letting it sit and will drain it later and try to wash out the last of the sludge.

While under there I noticed the output shaft seal was wet, and I had previously steam cleaned a lot of grease off the back of the transmission. That seal number is 591448 which NAPA crossed to a new seal for about $16, one of those is on order.

Here's a little trick I thought of for the u-joints to keep them together, perhaps it's been done before.
PICTURE
Used some wheel cylinder clips while removing the shaft to keep the caps on and not lose any needles.
Now would be a good time to replace the u-joints except they don't feel terrible and I want to deal with driveshafts later, so I'll reuse them for now.


Next post might be reinstalling the rear differential with 4.10 gears, or installing seat belts, or researching and thinking about replacing the wiring harness.

Grigg

Grigg where do you get all of the time for this? Do you have any to spare????

Actually I'd like to work on it more but don't have the time. What time I've had recently was half this past weekend and a half hour in the evening only a day or two the last few weeks.

When It first got home I did make more time to get brakes and things sorted out.

Hope to find more time after Christmas. Also keeping my fingers crossed I can get the rear axle back together and driving again before snow and salt. Pretty much decided I'm going to keep it inside after they salt the road.. That didn't used to concern me and It probably should have.

Grigg

Grigg, I have to tell you its' enjoyable watching this project. Since I have 2 almost "identical" 1-ton dually's.

My 6 wheels and seats were delivered in style from the sandblaster on Saturday morning by Jim "53 green 1-ton". Thanks Jim.....

They look great and I hope to find some time to prime them this weekend. Maybe finish coat if I could figure it all out. Best, joe

Big day today,
First a short followup post about transmission. (actually not so short but is simple)

Last we left it it'd been run (in the shop) with diesel fuel in it for a while and drained, still some sludge in the bottom so poured a little more diesel fuel in. That sat for a few weeks before and over Christmas. Today I drained the trans again, most of the sludge washed out. With a bent wire I scraped out some more sludge, sprayed some brake clean in the drain to wash the last out. The whole flushing thing worked out well.

Earlier I made a magnetic drain plug, I like to use them and they're sort of expensive to buy and cheap to make, so I make them.
Drain plug PICTURE 1
Drain plug PICTURE 2

The transmission output yoke seal seemed to be leaking a lot, time to replace the seal.
First to help remove the yoke I bought a handy, cheap, (but well made) tool. Though not entirely necessary on the transmission, it could be put in two gears at once, but it'll be most useful for holding the rear axle pinion in similar fashion.
Ratech Part number 18001 http://www.ratechmfg.com/Yoke%20tools.htm
Yoke holding tool PICTURE

Found that the bolt holding the yoke in wasn't very tight at all. I'm pretty sure the seal was leaking, and a good chance additional oil was leaking around the splines, washer, and bolt holding the yoke on.
PICTURE

The original seal is GM (I think) and Chicago Rawhide part number 591448. The replacement is SKF and NAPA number 22336.
Seal PICTURE

Removal and replacement was simple. The service manual suggest removing the whole rear cover to replace the seal. I just used a seal pulling hook, easier and no gasket to find/make, and replace.
To install the seal I used a little Permatex #2 on the outside, drove it in flush with the housing using a mallet and a round piece of stock larger than the seal and with a hole in it to clear the splined shaft.
Greased the sealing surface on the yoke and slid it back in. The washer had fretted on the bottom side so I turned it over, put some permatex on it, under the bolt head, and on both sides of the lock washer. The idea is to keep any oil that slips by the splines from escaping. Bolt gets torqued to 60-65 ft. lb. using that handy yoke holding tool.
Refilled with 80W90 gear oil, washed the shifter, smeared the moving parts with some grease and reinstalled it.

Next post, 4.10 rear axle gears!

Grigg

Several weeks ago I pulled the 5.14 gears.

Today I was actually doing a rear axle gear swap in between working on the transmission.

Here's a Tech Tip on this very swap.
http://www.stovebolt.com/techtips/axles/1%20Ton%20Upgrade/

Yesterday I picked up a crate with some 4.10 gears in it, shipped using Fastenal.
PICTURE
Here I've put my old 5.14 gears in the crate, picked one 4.10 pumpkin to use. Another Stovebolter will get the other 4.10 set, place two more 5.14 sets in the box and ship it back halfway across the country.
PICTURE

The new pumpkin and gears from 1970, also has the ratio/tooth count stamped on the ring gear, 10:41
PICTURE
Some serious rust around the yoke nut. No dried grease so I hope the seal is good. If the seal does need replacing later, now is the time to at least remove the rust and spray some penetrating oil.
Used a punch and a little hammer to chip away at the rust, there was plenty.
Also note the torched off and stuck pieces of u-bolts.
PICTURE

Two of the stuck bolt pieces came out OK with a C clamp and a socket.
PICTURE
Two of them were seriously stuck and needed more persuasion, one also needed some heat to finally budge.
PICTURE

Gave the pumpkin a quick wash.
PICTURE
After scraping old gaskets I use a flat file to remove any burs and dings, here's one spot cleaned up.
PICTURE
Also cleaned up the housing just the same, both sides. Used a somewhat dull bottom tap to chase the threads in the housing, all 20 holes. Finally cleaned out the inside as well.
PICTURE

Gaskets,
Pumpkin gasket; thin, and cover gasket; thick. PICTURE Ferl-Pro part numbers RDS 5090 and RDS 5988
I like to use Permatex #2 on most gaskets. Put a little on and spread it about as thin as possible with my finger, flip the gasket and repeat. Don't worry about loosing any when flipping, plenty enough stays on the gasket.
PICTURE
Also use the same Permatex on the bolt threads to seal them.
PICTURE
If I spread just the right amount on the gasket only the tiniest little bit squeezes out.
PICTURE
Also washed and removed any burs from axle and hub and put a new gasket on, Fel-Pro 55350. I didn't use any Permatex on the metal flange gasket because I'm not sure if it is a good idea? Time will tell if I should have. Did use Permatex on the axle flange bolt threads.
PICTURE


Continued in next post,

Grigg

4.10 gear swap continued,

Small diversion, axle breather was somewhat plugged with dried grease and the cap was loose, cleaned it, crimped it back on, some Permatex on the threads and reinstall. If it were thoroughly plugged the axle would probably leak somewhere when it warmed up.
PICTURE

Made up a pair of studs to help line up the pumpkin when installing.
Set the pumpkin on a creeper and rolled it under the truck.
PICTURE
Unfortunately no picture of the next part, I had my hands full. Laying on my back, feet forward and head under the axle I rolled the pumpkin on my chest and squirmed further under the axle. Looking through the axle housing back to front I picked the pumpkin up the last few inches and slid it on the guide suds (gasket already on the housing). Except it wouldn't slide on... I previously checked the fit of the pins on a bolt hole but not the exact two they needed to fit into, a mistake. A burr left by a lock washer was the trouble so set it back on my chest and moved the stud to another hole that it would fit into. Finally slid the pumpkin into place, the lineup pins if tested first actually work really well, easy.
PICTURE
The shop manual instructs to put the bolts in and "tighten firmly", no torque specification that I could find. For lack of a torque spec. I look at the specs for my 53 series Detroit engine which list a general torque spec for all common thread sizes. 35 ft. lb. seems about right for 3/8-24.
PICTURE
The rear cover has a thicker and soft gasket. As expected the cover was puckered a little at each bolt hole. With a hammer and a block of wood I unpuckered them, even a tiny bit past flat the other way. Because of the soft gasket and somewhat thin cover the bolts didn't need to be so tight, don't want to deform the cover at the bolt holes again, at least not by much. 20 ft. lb. seemed about right, 15 may have been just fine too.

This whole ordeal of cleaning and prepping, installing pumpkin, new transmission oil seal, refilling oil, installing driveshaft and backing the truck out of the garage took all day. I figured it might take half a day or so and thought I was nicely on schedule until looking at the clock to find out it was already 1:30...

Finally finished up about 5:30, quick shower and a test drive on the way only slightly late to a dinner invite.
Thankfully though the 4.10 gears are a very nice improvement over the slow 5.14 gears, made good time on the way to dinner, plenty of speed available. Much nicer to drive, didn't once find myself pressing in the clutch and searching for the next gear... to find it was already in high gear (a common occurrence with 5.14 gears).


Next post, hopefully just driving; it's time for plenty of that.

Grigg

"...a burr left by a lock washer" Wow, the little things that make you go HMMMMM! I changed out my axle breather to a new type, just couldn't trust that 'bottle cap' affair, I know, I know, it worked for GM so far...

Great work and documentation Grigg.

Looks Great Grigg. I have the same task on my "todo" list when I see you again. All good at ODSS North - Joe

Grigg,
you must have better ribs than I have. I think that beast of a pumpkin would go right through mine!

That is a nice writeup.

Grigg,

Cool to see the gears actually arrive and get swapped out!

I am saving every page of this post as a pdf.

Larry W.

Hi Grigg, great article. I suspect your running the original tranny, and if so if you have an idea how much speed you gained in top gear

Thanks JOHN

Thanks guys,

I think the pumpkin weighs about 80 lb, not so bad to pickup if you have to.

The difference in 5.14 and 4.10 gears is 20%
So drive same speed with 20% lower RPM or same RPM as before and go 20% faster.
Another way to look at it is a 4.10 gear change (with a direct drive transmission) is similar to having a 0.80 overdrive ratio with 5.14 gears. Same final ratio or speed in either case.
Hope that helps.

Today I stopped at a real neat vintage wiring place (close by!) and ordered an original type wiring harness. Only had time for a real quick, incomplete, tour of the place.... Must admit I am thoroughly impressed by the quality and attention to detail, to say nothing of the cool old machines, incredible inventory of components and finished products. On top of all that the owner is a wealth of knowledge and enjoyable to talk to.
Stay tuned for more wiring harness info in a month or two


Grigg

Grigg great job. Is it time to take a ride to Boones Mill?

Interested in your local wire harness business.

X2

Same on the wiring harness. Also looking for a source of bulb sockets for my gauge rebuilds.