Question about Cab 12 Chevrolet FAT
 

Hi All
I have a couple of questions regarding Chevy cab 12 FATs that I hope someone can help with.

Are the axles and brakes on a 1941 Cab 12 Chevy FAT same as on a 1944 Chevy Cab 13 C60? I have heard that they are.
If not, would it be possible to fit C60 axles on a cab 12 FAT? or where do I find brake parts for a cab 12?

Is it possible to find manuals and handbooks on cab 12 chevys anywhere ?

Pat 12 to Pat 13 interchange
 

Hi Neils

What you want to find is the later or Pattern 13 parts book, in most cases it will list the parts and where there is a difference it will will say something like early or late body style or give a serial number change over point.

In a general sense I think you will find that on the C60 and FAT Chev you will that the axles assemblies are interchangeable as units.

As to where to find brake parts first bit of confusion is that many Chev 3 Tons used FORD brakes, now as to the parts and where to find them it will depend on what you need. Brake lines etc are relatively easy to find as there are modern equivalents. Brake cylinders, in my experience have them sleeved the sleeved will out last NOS or new parts many times over.

There are several good threads about brake parts on MLU it takes a little searching to find them.

I have a lot of photos of the Axle assemblies for the Pattern 12 and 13 C60 on my web site.

Keep us posted on your progress.

Cheers Phil

I will see if I can find a parts book then.
I have bought a 41 Cab 12 Chevy fat in reasonable condition, but it is missing all "internal" parts in the front brakes: Liners, springs cylinders etc.
and I have 44 Cab 13 C60m that is getting broken for spares so I was wandering if I could use the front internal brake parts from the C60 for the FAT, or if had to replace the whole axle (front and rear)
It will be awhile before the FAT is delivered because of paper work and it is in another country, and therefor I can not check if the parts are the same.

Niels,

I am not sure, but would hazard a guess that the brake parts are the same as the CGT used the same mechanical components as the C60 3-tonners. Would be best to save the C60L's complete axles if you have the space, otherwise save the brake back plates, internal brake components plus drums. That should give you enough options for the CGT while you go through the parts lists and sort out the details. I'll check my manuals to see if I have the info.

Hanno

All the mechanical part and the original body parts will be kept from the C60M but most of the body work is postwar danish and rotten so thats going in the bin

A word of caution......
 

Some early Chevrolet Gun Tractors....Also knows as CGT had the specail heavy duty casted from axle which differed from the typical CMP later production front axle. ..... and from my experience and photos ...that special Heavy Duty cast axle had similar eggcups mountings and brake plate of a 16 inch CMP front axle.....
.....................even when 20 inch rims were installed.

Early cab 11 CGT had that front axle one is at the Kars Museum.... I also found such a large axle on a 1942 C15a ....... but it is the 4 bolt eggcup which would not exchange for the larger C60 axle......

Now to complicate things early FAT also known as Ford Artilery Tractors also had GM front axles.......

So my advice is save all you can from the C60 if they do not fit they can always be traded for other parts later...... once you have you gun tractor home start taking pictures of your front axle so we can identify it for you on the forum.

Photos 1,2,3 are from the Kars cab 11 CGT photo 4 is the same CGT with rare early cast GM rear axle
Photo 5 is Petrolia's famous Ford FAT with GM axle.

Little More Information
 

Hi Niels

According to the MB-C1 Manual C-30, C-60 and C-GT all share the same axle gear ratio 7.16 to 1 so a unit swap should be OK from ration point of view.

What is interesting is the track FRONT and REAR

C-30 Front 70" and Rear70 1/2" Tire Size 10:50x16
C-60 and C-GT Front70 1/2" and Rear 69" Tire Size 10:50x20

But as has been said the best way is going to be to look up the parts numbers for the different units. If you are going to acquire reprints of the manuals, parts book you should also try and find a set of the service bulletins as there is a lot of useful information in those as well.

Service Bulletins -B-62 for example has detail information on spring rates and what is interchangeable with what. One of the things that comes out in that is that the 1941 FAT and all 3 tons had 10 leaves and 1950 Load rating while the 1942 which would be Pat 13 it jumps 15 and 2900. (I'm not sure of the number of leaves at 15 may be incorrect.)

CMPs a lovely jig saw puzzle.

Cheers Phil

Thanks
 

Hi guys
Thank you very much for your answers.
I will have to see what it has when I get it home, Sadly I didnt get proper pictures of the front axle on it, only these.
It had, by the way, some very nice rear tires on.

My conclusion.....
 

From the pictures you have just posted your front axle is the lighter model intended for 16 inch rims such as CMP C15a......although the larger 20 in. tires will fit quite well and the gear cluster may have been changed to the 7.16 ratio as it will bolt in.

From my experience the brake drum and all brake components of your gun tractor will not interchange with the brake parts of a C60 front axle.

Bob C

Better pictures
 

Here are a couple of better pictures of the axle

Lighter model
 

In my understanding the front axles for 3 ton payload CMPs were all the lighter (4 7/8") type until the 6" steering ends were introduced sometime in 1942. So the axle shown is correct for your vehicle. The brake drums for the 6" type were a lot wider.
The 4 7/8" type steering ends were then used only on the lighter 15CWT and 30CWT models.

Photos of 1941 Pattern 12 Axle Units
 

Hi Niels

The photos and comment are confirming that the axle and brakes are the same or nearly the same as the front axle on my 1941 Pattern 12 Chev 3 ton.

So for more photos of the axles go over to my web site http://canadianmilitarypattern.com/ and look at the section on Pattern 12 or jump directly to the axle page http://canadianmilitarypattern.com/P...eRemoveal.html Remember to click on the pictures if you want a larger picture. If you need more detail on any of the photos just post your question and which photo. I'll be glad to post a larger higher resolution link.

I've been able to find most of the brake parts, the only thing I really have not looked for is brake shoes, but there is a photo of the basic dimensions for the front and rear axles shoes.

Cheers Phil

Thanks
I will study it

Home at last
 

Finally the export documents cleared and I could collect my newly acquired Chevrolet cab 12 GT.
It is fitted with a post war chevrolet engine, ist running and driving nicely but no brakes (there is nothing inside the front drums...)

Cgt
 

She's beautiful Niels!

Definately! lovely project Niels. Even though part of the rear has been cut, the remaining portion seems to be pretty straight.
Alex

Ford FGT Parts Manual
 

Niels,

I was fortunate to get my hands on a FGT-01 Ford Illustrated Spare Parts List manual for my Cab 12 Ford FGT. It has many expanded parts drawings and references both the Ford and Chev versions of the FGT's. If you need higher resolution pictures or more information, let me know via PM or by email.
Good luck with your restoration!
Regards, Richard

Thank you very much guys, Even though it looks a bit rough it drives really well, the engine runs smoothly with good oil pressure, but it dos not charge.
Richard I will be interested in any pictures or drawings of the rear body and crew compartment and all other chevrolet parts drawings.

Do any one know where to get wheel and master cylinder seal kits for it or part numbers of those ?

She's a beauty, Niels! Sounds like a great buy :thup2:

I'm not at home with Chevrolets, but for brake part numbers try searching the thread Modern part numbers for CMPs. IIRC, the brakes are identical to Ford CMPs, except for the master brake cylinder.

HTH,
Hanno

Confirm the size of the brakes?
 

Hi Niels

Could you confirm the diameter (ID) of the drums and how wide the braking surface is? With that I can start looking back through my parts replacement history and see if I can come up with what modern part numbers I have found and where I found the parts.

Couple of general observations about brake parts.
Most of the hardware springs clips etc are still available new.
Brake cylinders can be found NOS or New here in the states but I would go with finding used ones that can be sleeved with brass or stainless. My experience is that NOS cylinders only last 3-5 years before pitting. I've got some sleeved ones that are 25 years old though I generally replace the rubber cups and the hoses every 10 years.
I have never need to find brake shoes, though I have had old ones relined.

Your truck looks great, I think the FATs are the iconic CMP that most of us would secretly like to own. (I say secretly just in case my wife reads this, 3 CMPs on the road at once really should be enough.)

Cheers Phil

Thank you guys.
I hope to take a look at the brakes in the coming weekend and will get the diameter and width then.
I will need a set of front wheel cylinders, (they are missing)
I my world the FAT is the iconic cmp, but that is mostly do to a Tamiya model kit ;)

FGT Brake Schematic
 

Niels,

I sent you a PM with higher resolution .pdf files of the FGT brake schematics. f you can take a look at the attachments and send me back a list of the Part#s that you need information on, I can cross reference the FGT Part#'s with the Part Name Description in the Ford FGT-01 Spare Parts manual.

Hope it is not snowing yet where you are!

Richard

Thanks Richard
What is the easiest way to get to the master cylinder, from the top og bottom?
I have found that I am missing a rod that goes across the top of forward part of the engine compartment just behind the radiator.

no way near snow yet its 13C here.

I had a chance to measure the brake drums, they are 15 inch high and the braking surface is 2,5inch roughly ( I could not get the drum of)
From what I could see there was nothing inside the drums.


Is it possible to find a new wire guide/D towing eye? otherwise can any one take some closeup picture of one so I can recreate mine.
At the moment there is a normal one bolted on top of original one.

Winch Fairing Info
 

Hi Niels

Take a look at the photo from the parts book, note that the top and bottom shafts and rollers are the same part numbers. So you should be able to fabricate a new lower shaft based on the top shaft.

Bottom shaft was missing on my Patter 12 as well.

Looking at my log photos from restoring my Pat12 C60L it looks like the brakes front and rear are the same basic units so when you disassemble one of the rear brakes you should be able to check to see if the parts are interchangeable then you can start hunting parts based of an comparing to the rear. I have quite a few fairly hi resolution pictures of the front and rear brakes if you would like I can post them.

Cheers Phil

front towing clevis
 

Niels,
Here some pictures of my front towing clevis (D-eyes) left side.
GM was using a pin with round head and a washer with cotterpin on
the underside.Ford was using a hex bolt with castelated nut and cotterpin.
Hope this help.

right front towing clevis
 

and that's the one for the right front side.

Mix of Chevy and Ford Parts
 

Hi All

I forgot to mention that the parts break out I posted for the front Winch fairing was Ford. But my Pattern 12 C60L is of course a Chevy, CMPs are often a wonderful mix of parts both some of this is from swapping of parts for repair purpose but much of it is as built. In a what today would be rare cooperation between manufacturing companies FORD and Chevy seemed to swap parts and more important manufacturing capacity back and forth, to get the job done.

Cheers Phil

Thank you guys.
Yes they must have mixed because the towing clevis on my CGT are the ford type with hex bolt. one of the bolts are sadly broken

Pat 12 Brake Shoe Size
 

Hi Niels

Well I found the photos and measurements for my Pattern 12 C60L which has the smaller diameter drums.

Front and Rear Shoes are different my photo notes show the fronts as being 2" wide and the rears as being 3 1/2" wide.

Also found the brake cylinder information and source (will somebody help confirm these) the source is MAC's Antique Auto Parts .

These number match the CMP parts book and MAC's shows them as having them Rear 91T-2261 1 1/2" diameter Fronts 92Y-2261 1 3/8" diameter (note you have to type it into their side with the dash)

Cheers Phil