Fuel tank cap ID.

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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Miles Through Time
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Fuel tank cap ID.

Post by Miles Through Time » Mon Aug 02, 2021 10:43 am

Need a cap for aM38A1 on display. It has an aftermarket cap on it that catches my eye every time I pass by, so we'd like to put a correct cap on it. When we go to the parts drawer, we have three different styles that seem to fit and all have the little chain on them to connect to the tab inside the fill neck. No strainer in the neck.
From left to right, 1, 2, 3

1 is vented and has two upright tabs on it and is identical to one we have on a M37 and has the vent on the underside of the cap.
2. Has no tabs but has the vent under the cap. Goes on but is loose, may need new gasket.
3. Has the two dog ears on it and fits perfectly. Has the chain, does not vent and has no ability to do so.

Presume 2 is the one we are needing and will try new gasket if that is correct. Any helps with ID on 1, 2, and 3 would help us tag them for future use or sale.

Thank you.
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muttguru
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Re: Fuel tank cap ID.

Post by muttguru » Mon Aug 02, 2021 1:12 pm

Miles Through Time wrote:
Mon Aug 02, 2021 10:43 am
Need a cap for aM38A1 on display. It has an aftermarket cap on it that catches my eye every time I pass by, so we'd like to put a correct cap on it. When we go to the parts drawer, we have three different styles that seem to fit and all have the little chain on them to connect to the tab inside the fill neck. No strainer in the neck.
From left to right, 1, 2, 3

1 is vented and has two upright tabs on it and is identical to one we have on a M37 and has the vent on the underside of the cap.
2. Has no tabs but has the vent under the cap. Goes on but is loose, may need new gasket.
3. Has the two dog ears on it and fits perfectly. Has the chain, does not vent and has no ability to do so.

Presume 2 is the one we are needing and will try new gasket if that is correct. Any helps with ID on 1, 2, and 3 would help us tag them for future use or sale.

Thank you.
MTT....

Cap no.1 fits the M151 and M151A1. However, these caps have ears which either rip trousers on exit or rip flesh plus trousers.
The Military advised flattening the ears to make them safer to use following reports of damage and injury.
Your M38A1 would most likely use cap no.1.....the "ears" cap because there is little chance of the driver making contact with the cap when exiting the vehicle. And ORD 9-SNL G758 shows that very type of cap.

Cap no.2 looks like the replacement cap (around 1968-69) which has a milled edge (like a coin). It fits the M151, M151A1 and the early M151A2. This was better than the "ears" type but was difficult to open and close while wearing gloves.

Cap no.3 is the one used on 1973-onwards M151A2 with Emission Controls. The "ears" are on the edge of the cap, not on top.

Cap no.4 (not shown here) is identical externally to the cap no.3 except it is vented.

You can see more on these caps by going here: http://www.g838.org/viewtopic.php?f=3&t ... ap#p105083



Ken
Contact address - muttguru@aol.com
Always wanted - Details and pictures of M416 Trailer data plates & M151 data plates & body-tags for my research. Thanks!

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