Trying to get two m220's running after a long rest

Hi all,
New Steel Soldier forum member here. I’m attempting to get two M220’s running again. Our daughter and son-in-law have purchased his family’s farm (he’s 4th generation on the farm) and are working hard to make it go. These two trucks were used on the farm years ago and have been sitting for a long time. He’s asked me to see if I can get them going. Once we know whether or not they’ll run, he’ll decide what to do with them. Maybe use them on the farm, maybe sell them and use the $$ to buy other equipment. I’m glad to be able to help them. I’m also hoping to save these two good old trucks from the scrap yard. And, if I’m lucky, I may end up buying one of them when this is all done.

I own two M38a1’s. One runs, one is still in “kit” form. So I have a little experience working on military vehicles. But I know almost nothing about these bigger trucks so I’ve been reading posts on this forum and talking to mil veh folks I know.

As you can see from the pictures, these M220 “shop van” trucks lost their “shop” a long time ago. They’ve been wearing those potato beds for many years.

Here’s some info on these trucks:
1. Both still have the original data plates and other dash plaques. Hood numbers are painted over but can be seen.
2. Sheet metal on both is solid with virtually no rust through. Roofs are slightly caved in.
3. Both cab interiors are in good, original condition.
4. Both trucks still have the original 6 cylinder GMC engines in them. One is free, one is frozen.
5. Both trucks still have the original 24V equipment. Wiring appears to be in pretty good shape.
6. Both original automatic transmissions have been replaced by manual transmissions. A local mil veh collector thinks the conversions may have been done at Boyce down in Utah.
7. Truck 1 odometer reads 5,885, truck 2 reads 7,520. I haven’t determined yet whether or not the speedos worked after the switch to manual trans.
8. The frames have been stretched in two places: in front of the rear wheels and at the end of the frame. According to the data plate, stock overall length, front of bumper to end of frame, was 268 3/4”. Their current total length is approx 312”.
9. Most of the tires are holding air. Some are rotten and will need to be replaced.
10. We think they were both running when parked, but not 100% sure about that.

If the engines will run, then I’ll work on the clutches and brakes, get good tires all around, check the steering and take them for drive!

I’m hoping to get all that done w/in the next 4 – 6 weeks. I’m sure I’ll have plenty of questions along the way. I’ll try to do my homework and not ask too many dumb ones.

I welcome any info, questions, or suggestions you might have.

Jack

Here are some pictures:

Truck 1



Truck 2



Truck 1 dash



Truck 2 interior



Truck 2 transmission



Truck 2 transfer



Truck 1 engine



Frame extension in front of rear wheels



Frame extension at back of truck



Truck 2 pedals



What's next? I'll be starting work on this one shortly. 1966 Kaiser Jeep M35a2. It's not as bad as it looks! I'll post a thread in that forum once I get started.

M220

Great post and welcome to the SS Early Deuce.

Thank you for sharing the great pictures. I know some boys that would love to
see detailed pics of the modified drive train. The stupid question I usually ask myself is , " Why didn't I listen and read the Technical Manuals (TM's)".

That said, ask away.... I have all the 'stupid question' answers covered.......except these.

If the original motor bolted direct to trani.........make and model of trani?

How was trani mounted? original mounts or modified?

Was the frame lengthened to accommodate the box?.......or the drive train too?


What year(s) are the trucks??.........Is CDN stamped on the data plate??



....We plant and harvest potatoes using our 1950 ferguson tractor and 50's implements. Seeing a 50's potato hauler, stirs up all kinds of ideas and memories....


.....Absolute congratulations on the projects ahead.....once all the air-intake, carb, fuel lines, engine oil and spark has been R+R'd (remove and replace) .....and if the exhaust is solid......you will be so pleased to hear the purr that in-line 6 makes.

Keep the progress and pics coming. Let us know what you need.

Welcome to the site. Except for the frame cuts, the trucks look like great candidates to be fixed. The troublesome Hydramatics are gone already. The trans is a Clark out of a WWII GMC CCKW deuce and the transfer is a 2 speed GM also out of a banjo WWII GMC. The flywheel housings are also CCKW. The flywheels are the hard to find 6 bolt units for the GMC straight 6's (civilian). You will have to rebuild the entire brake system, and that is many days of work. Good luck!

Welcome to Steel Soldiers. THANK YOU for the pictures! I see a lot of potential there. (extended or 4 door cab or find 3 beds and make 2 long ones)

Question: Could they be M135 models? I ask because they have single rear wheels and the hubs look to be M135. M220 had them a little differences in the rear hubs and Dual wheels.

Keep us posted. We look forward to hearing more!

Great find! I am loving truck #2. It looks like they retained the 302 too, so that is very cool.
What you have here is a very sound albeit a little bit jerry rigged drivetrain swap.

NDT has it correct in that the tranny is a Clark 5 speed and the transfer is a Banjo 2 speed unit both from a CCKW truck. It was widely rumored that the CCKW transfer would bolt right into place of the M211 series transfer, your pictures prove this rumor to be correct!!

The CCKW transfer was used for the 2.72 (or thereabouts) low range. Since low range was lost when the Hydramatic was dropped.

The large flat bar stock lever could be 1 of 2 things. It could be the high/low/neutral lever. Or it could be the lever to engage or disengage the front axle. I am not too familiar with the CCKW transfer but it should all be simple stupid.

It's a great setup, I look forward to seeing more pictures of it. It would be sweet to see this truck restored from the top down. But also retain the CCKW drivetrain for driveability reasons.

Don't kid yourself. When GMC was developing the G749 series they did experiment with using the existing CCKW drivetrain. I am sure any prototypes are long gone and in China. Or the $1 bin at walmart somewhere.

Forgot to add, Boyce did thousands of these power swaps over the years. Give them a call and speak with any shop guy and he'll tell you anything you need to know.

Ask lots of questions on here too! Lots of guys on here who know more about the GMC's than people could have dreamed about years ago. Wonderful resource the net. Glad to see 2 more GMC's rediscovered.

Thanks to all for your good replies! I can tell that this project is going to stretch my limited knowledge and skills and I appreciate your info, questions and comments.

I'll add a clarification: both trucks are almost exactly alike. I've posted some sample pictures of "truck 1" or "truck 2", but if you see something on "truck 1", then "truck 2" will most likely have that same thing on it. I'm guessing that they were both converted at the same time and place.

Plowboy - I'll work on getting some clearer drive train pics; I'm guessing the frame was lengthened for the bed since it goes right to the end of the lengthened frame; both trucks are 1954, truck 1 is March, truck 2 is January; I don't remember seeing CDN on the plates, but I'll check again. Planting spuds with a 1950 Ferguson? Very nice!

NDT - thanks for the info on the trans and transfer, I was hoping someone would be able to identify them from the pics; rebuild the entire brake system? oh boy!

hendersond - M135? The data plates say they are both M220's. I'm guessing that the singles were installed and hubs changed as a part of the conversion that was done. Maybe the change to singles was done to save some $$? 4 tires are cheaper than 8?

gunfreak - thanks for the followup info on trans, transfer etc; and the info on Boyce, I'll have to give those guys a call. Actually, there are two more trucks on the place I haven't mentioned yet. I know for sure that they are Boyce conversions because they have the Boyce fiberglass hoods that tip forward on in place of the original front sheet metal. The name "BOYCE" is prominently displayed at the top of the hood. I'm not sure what chassis they are, but they are definitely military. I've decided to focus on the M220's and the M35a2, so the two Boyce trucks are going to sit for a while longer. Maybe I'll start a new thread and post some pics to see if anyone can give me some info on them. One is probably just a parts truck, but the other one my son-in-law remembers backing into the potato cellar the last time it was run some years back. It still sits right where he parked it.

Jack

Clutch system?

The clutch system on these trucks consists of two cylinders, one mounted on the outside of the frame underneath the drivers door and one mounted to the bell housing. The clutch pedal is attached to the frame mounted cylinder and a steel line runs from it to the one mounted on the bellhousing. The bellhousing cylinder actuates the clutch.

Both are frozen on both trucks, so I'm guessing probably rusted and pitted inside and will need to be replaced. Anyone recognize the cylinders? Source for new ones?

Jack

Frame mounted cylinder



Bellhousing mounted cylinder

targhee trucks said:

they have the Boyce fiberglass hoods that tip forward on in place of the original front sheet metal. The name "BOYCE" is prominently displayed at the top of the hood.
Jack

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Definitely worthy of some pictures. Thank you for your posts

The brake system is pretty simple. When people think air over hydraulic they think of an overly complex system with a crap load of hoses and lines. In reality most of the large steel hard lines running in the frame are for the chassis vent system which is basically a closed loop that connects all the gearboxes, fuel tank, engine breather, air compressor etc into the air intake under the hood. It was for fording reasons.

The brake system is completely hydraulic like those on any pickup truck. However instead of being boosted by hydraulic fluid from a power steering pump (aka hydroboost) or manifold vacuum (hydrovac) the GMC's use air pressure generated by an engine driven air compressor.

The air compressor pressurizes the two tanks under the frame. The AIR PAK is a simple design and very reliable if serviced regularly. It is also known as a power converter. It works by basically using the air pressure from the tanks to operate a huge 4" piston which then compresses a smaller piston which in turn pressurizes the brake fluid going to each wheel cylinder. So the AIR PAK itself is nothing more than an over glorified master cylinder.

Your primary master cylinder operated by your foot is simply acting as a control valve for the AIR PAK by sending pressurized fluid to the AIR PAK's poppet valve. Which tells the AIR PAK to basically turn off and on for braking. In a nutshell.

You'll want to rebuild the AIR PAK which we can help you with. Replace or rebuild all 12 wheel cylinders. Inspect your 12 brake shoes. Replace all the brake hard lines and flex lines.

We spent yesterday fixing fence on some summer pasture getting ready for a load of cows coming in today, so no progress on the trucks. Here's a picture from the front seat of my A1. Conant Creek canyon, Tetons in the distance.



plowboy - No CDN on the data plates, here's a picture of the plate from truck one



hendersond - I did manage to get a few pics of one of the Boyce trucks yesterday, I'll get some of the other one and then post a thread

gunfreak - Wow! Great post on the brakes, thanks for taking the time to do all that, it will be very helpful.

Pouring rain at the moment, if it clears up I think I'll have some time to work on one of the trucks before we have to go meet the cows later today.

Boyce Equipment

I've sent an email and some pictures to Boyce Equipment of Ogden, Utah, asking if they can tell me whether or not these trucks were converted at their shop. I also inquired about parts. Their website said that replies take several days, so I'm hoping to hear back from them by the end of next week.

Here's a link to their website: Boyce Equipment Axles and Military Parts

Is your M220's serial number 711? Mine is also a 54 and is serial 638.

Really makes you realize how few GMC were made compared to the M35's.

Gunfreak25 said:

Is your M220's serial number 711? Mine is also a 54 and is serial 638.

Really makes you realize how few GMC were made compared to the M35's.

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Thanks for asking the question about the serial number. Yes, the number on the plate is 71 (space) 1. The fact that there is a space between the "71" and the "1" makes me wonder if it is some kind of a code that tells us something about where or when it was built? Or is it just a sequential number without any other meaning?

There should be more to the serial number. On the passenger side frame horn (outside) forward of the front axle there should be some numbers about 3/4 of an inch tall . In the case of my M220, it took some sanding to find them under all the paint. The number should start "M220" followed by a space and then a letter and then numbers. The letter Y signifies 1955 (in the case of my M220) and then I have 3 digits for a serial number. (Example M220 Y ***) My M220 was manufactured late 1955 and delivered to the Army early 1956. Because it was delivered in '56, many have assumed my truck was a '56 rather than a '55.

"year bracket" ( A='39-'40, C='41-'46, E='46, F='47-'50 Z=54, Y='55 , X='56 , T=57, S='58/'59, N='60 ).

That is odd. Mine just say's M220 638. (I'd love to return it to 220 status someday)

Gunfreak25 said:

That is odd. Mine just say's M220 638. (I'd love to return it to 220 status someday)

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That might be because from 1951 through 1953 GMC did not use a letter for a date code. If your truck was manufactured in 1953, but delivered to the Government in 1954 it would not have had a letter in the serial number.

On the other hand, maybe GMC changed the way they did their Military serial numbers between '54 and '55, but as near as I can find out, the system they used through the 50's was based on their civilian system with the Truck series (M220) used in place of the cab, drive, and accessories codes followed by the year letter (in the years they did that) and then the serial number.

OF knows his beans.

Can you post your pics here instead of links? Thanks.

Oldfart said:

There should be more to the serial number. On the passenger side frame horn (outside) forward of the front axle there should be some numbers about 3/4 of an inch tall

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Thanks for that! I've wondered about the serial number, seemed that there must be more to it. Good timing on the answer too, because we're going to start searching through the files his dad left him and see if we can find titles. If there are none, we're going to have to go through that process. I'd like to be sure the correct vins are on the titles.

I'm going out to do some work on the trucks this morning, I'll check those frame horns and let you know what I find.

That is one fine looking truck and trailer in your avatar, very nice!

Jack