pressurized gas tank on 420C

traber1 · Post by **traber1** » Tue Aug 09, 2016 12:07 pm

Had a scary and very unexpected event over weekend. Had been dozing a brushline and decided to check gasoline level before moving deeper into woods. Loosened gas cap and it blew up and away from my hand. I then had a fountain of gas streaming from the tank port, spraying on me and a hot engine.

Does anyone know if this gas cap is supposed to be vented in both directions or did Deere do something very genius and use thermal expansion in place of a fuel pump?

Stan Disbrow · Post by **Stan Disbrow** » Tue Aug 09, 2016 1:05 pm

Hi,

No pressure on those. There is a vent line which heads downwards as it also acts as an overflow line.

Yours is plugged. Probably by a mud dauber wasp nest.

Stan

Edit: Or, bent plugged. I have seen that, too.

Stan Disbrow · Post by **Stan Disbrow** » Tue Aug 09, 2016 1:06 pm

Hi,

Ah. The double post after an edit right after the main post bug strikes again!

Stan

notmeu · Post by **notmeu** » Tue Aug 09, 2016 2:30 pm

Stan Disbrow wrote:Hi,

No pressure on those. There is a vent line which heads downwards as it also acts as an overflow line.

Yours is plugged. Probably by a mud dauber wasp nest.

Stan

Edit: Or, bent plugged. I have seen that, too.

Stan I never noticed this vent line on a 420 gas tank. Where is this vent line located? The only connection on the gas tank that I ever noticed was for the fuel line bowl.

Post by **Lavoy** » Tue Aug 09, 2016 2:48 pm

Early 420 will not have a vent line. It is possible you have a non vented cap installed.
Lavoy

notmeu · Post by **notmeu** » Tue Aug 09, 2016 3:31 pm

Lavoy wrote:Early 420 will not have a vent line. It is possible you have a non vented cap installed.
Lavoy

That makes sense lavoy, I have a 56, 420. And I am 99.9% positive there is no vent line. My gas cap does hiss from time to time to release the tank pressure. So traber1 you must not have a vented cap installed or something went wrong with the gas cap.

Stan Disbrow · Post by **Stan Disbrow** » Tue Aug 09, 2016 5:00 pm

Hi,

Ah. Yet something else to store away in the wetware.

My 420c is a 58. And I have had several 420 and 430 wheel tractors. All had tank vent lines (that mud daubers like to plug up, and a couple where POs had managed to mash shut as well).

Stan

PO = Previous Owner....and....exactly what else it *usually* means!

There is a new tag line for someone: Nothing will P*** you Off like a Previous Owner!

Stan Disbrow · Post by **Stan Disbrow** » Tue Aug 09, 2016 5:29 pm

Hi,

Come to think on it, my 1950 M does not have the gas tank vent line, but a vented cap....which dribbles gas out the top if I overfill it and it expands faster than I burn it.....

Stan

Paul Buhler · Post by **Paul Buhler** » Tue Aug 09, 2016 5:50 pm

My 1958 420 has a vent line to nowhere, and a vented cap. The PO thought of every thing.

Actually, I don't want to make fun of this person. I see that he did a lot of good but cash strapped maintenance over the years while working his dozer hard. It is still a strong machine serving me well - fingers crossed.

traber1 · Post by **traber1** » Tue Aug 09, 2016 6:01 pm

Thank you gentlemen. I don't recall seeing a vent line, but with the chance of becoming a human torch, you can bet I will install a good venting cap.

notmeu · Post by **notmeu** » Tue Aug 09, 2016 8:02 pm

Stan Disbrow wrote:Hi,

Come to think on it, my 1950 M does not have the gas tank vent line, but a vented cap....which dribbles gas out the top if I overfill it and it expands faster than I burn it.....

Stan

Yes Stan, the gas dripping out of the cap sounds familiar. I have learned to only put two or three gallons in the tank at a time when needed to prevent this. My J on my John Deere sticker on the hood was starting to get deformed quickly because of this! These crawlers sip the gas anyways!

Stan Disbrow · Post by **Stan Disbrow** » Tue Aug 09, 2016 8:44 pm

Hi,

I keep them near full, 10 gallons or so of 100 octane unleaded. As the gummint keeps futzing with pump gas, I kept on upping the mix until I just use all racing fuel. But, one does not want that stuff leaking out. It ignites far easier than the usual crap does.....

Stan

Gil · Post by **Gil** » Wed Aug 10, 2016 8:07 pm

The vent was added at serial number #126977. You can see a line drawing of it in the 420/430 Parts Manual. Gil

notmeu · Post by **notmeu** » Thu Aug 11, 2016 5:27 pm

Thanks Gil, I'm curious to see where the vent is located. I'll take a look at my parts book, if I can remember where I put it!!!

Paul Buhler · Post by **Paul Buhler** » Thu Aug 11, 2016 9:06 pm

Page 15-12 of parts catalog.
http://t.jdpc.deere.com/jdpc/servlet/co ... #mw_search
Type in "420" for model. Scroll down to "505"catalog.

Updated Note: Link was established on an I-pad. apparently, a PC gets different results.
Try This link instead:
http://jdpc.deere.com/jdpc/pdfs/PC0505.pdf
it takes a while to download.

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pressurized gas tank on 420C

pressurized gas tank on 420C

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