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Allis Chalmers C gas tank

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=211998
Printed Date: 17 Sep 2026 at 4:38pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com


Topic: Allis Chalmers C gas tank
Posted By: edvalovage
Subject: Allis Chalmers C gas tank
Date Posted: 16 Aug 2026 at 3:22pm
uploads/25702/gas_tank_1.jpeg" rel="nofollow - uploads/25702/gas_tank_1.jpeg

uploads/25702/gas_tank_3.jpeg" rel="nofollow - uploads/25702/gas_tank_3.jpeg

Hello, I have an Allis Chalmers C that I am restoring. All photos I see of the C have a mounting strap on top of the gas tank, operator end. Mine does not have this. It has brackets on the bottom that bolt to the "tool box" structure below it. Were some Cs built this way, or has mine been modified with a tank from some other model? Any thoughts appreciated.

I attached two photos.

The serial number is in the 5,000s so a fairly early one.

Regards,
Ed



Replies:
Posted By: john2189
Date Posted: 16 Aug 2026 at 3:53pm
The strap is to hold the front of the tank and the hood down.

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'41 Allis B
'49 Farmall Cub



Posted By: steve(ill)
Date Posted: 16 Aug 2026 at 6:21pm
i have one B that is pre 1940 and it has two tabs welded to the bottom of the tank and a horizontal bolt holding to the frame at the very back / bottom of the tank.... I have 6 other B tractors built after 1942 and they all have the single strap on the top,  pointed toward the rear, with one bolt down thru the strap ...........

All of the B and C tractors have the wrap around strap at the FRONT holding the gas tank down to the tank mounting block.


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Like them all, but love the "B"s.


Posted By: steve(ill)
Date Posted: 16 Aug 2026 at 6:26pm
here is a photo of my 1940 model B tank.. You can see there is no STRAP on the top rear of the tank.. The mount is not visible, but i seem to remember two tabs welded to the bottom of the tank that straddle the steering column tube, with a horizontal bolt holding the to the tube.




-------------
Like them all, but love the "B"s.


Posted By: steve(ill)
Date Posted: 16 Aug 2026 at 6:37pm
this shows the rear strap on a 1948.....(. i have a 1942 that may also have the two small tabs on the bottom with the horizontal bolt.. old phot seem to show that.)




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Like them all, but love the "B"s.


Posted By: edvalovage
Date Posted: 16 Aug 2026 at 6:49pm
So the thing is; I have no strap; front or back. The images I see have a strap in the back, operator end, not radiator end, that would hold the back down. I have no strap there. I'm not concerned, I'll put it back together just fine, securely mounted. 

My question is a historical one; were some (maybe early) model Cs made this way (no srap), or is mine some retrofit from other models?


Posted By: edvalovage
Date Posted: 16 Aug 2026 at 7:03pm
Following up (I'm the OP) I see Steve's photos showing the difference. My C looks like his 1940 B photo. So it's looking like early Cs were like the B, mounted from the bottom with no straps showing. No big concern, just wondered about the history. 


Posted By: steve(ill)
Date Posted: 16 Aug 2026 at 7:09pm
since they built Cs in  1940 - 1941 , im guessing the first Cs would have had the tabs on the bottom of the rear... just like the B....

All of the B and C tractors had the FRONT STRAP to hold the tank down to the  cast saddle.


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Like them all, but love the "B"s.


Posted By: steve(ill)
Date Posted: 16 Aug 2026 at 7:14pm
this is what GOOGLE AI says it found on the internet... but like i said, i have a 1940 and a 1942 that have the two TABS on the bottom..

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On the https://en.wikipedia.org/wiki/Allis-Chalmers_Model_B" rel="nofollow - - Allis-Chalmers Model B tractor, the early fuel tank configuration relied on a direct soldered/welded rear mounting bracket. The transition to an overarching strap design tied to the rear/steering column area happened during the 1939 production year around serial number 3100, shifting the orientation and mounting style as part of early-run factory updates. 
Design Evolution Details
  • Early Style (1937–1939): Featured a rigid, direct-welded or soldered rear bracket attached straight to the tank shell. 
  • Transition Point (Serial ~3100 in 1939): Introduced a flexible strap layout to better absorb chassis vibration and reduce stress fractures at the soldered tank joints. 
  • Later Style: Utilized a band/strap configuration wrapping over the assembly to anchor the rear tank section near the steering column and instrument/toolbox area


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Like them all, but love the "B"s.


Posted By: john2189
Date Posted: 16 Aug 2026 at 7:26pm
Originally posted by john2189 john2189 wrote:

The strap is to hold the front of the tank and the hood down.


Sorry, I misread what strap you were referring to.

-------------
'41 Allis B
'49 Farmall Cub




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