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‘37 gas tank
#1419093 Mon Aug 02 2021 12:19 AM
Joined: Dec 2019
Posts: 177
3
37 GC Offline OP
'Bolter
Not really engine, driveline, interior and definitely not electrical, but here goes. The under the seat tank with the filler bung under the passenger seat…got it out to clean up and coat with some paint.I knew the supply line was toast when I got the truck home and started defarmerizing all the bailing wire, the gas shut off was broken off and crumpled up in a wad of fuel line dragging under the truck. That is easy, but how about that bragged about in the Chevy advertising vent line? How did it work, where did it go and how can I reproduce it? It is completely missing and obviously broken off also. I’m assuming the other bung on the top that comes off (other than the fuel gauge sender) works with that vent as it seems to have some kind of check valve. The pic is the underside. Left is vent, right is fuel line and top is a drain. Wanting to stay original if I can get it all to work.

Attached Files
E1795076-4FAB-4B19-976E-E5A71EB3F32F.jpeg (261.16 KB, 75 downloads)
Underside of ‘37 gas tank

Larry
All you need in life is TIME, PATIENCE and MONEY.
If you are missing one component, you'll need an abundance of the others two.
Re: ‘37 gas tank
37 GC #1419097 Mon Aug 02 2021 12:39 AM
Joined: Apr 2007
Posts: 889
L
'Bolter
Larry,
No, the vent is not broken off. You are looking at it. The vent hole is lined up with a corresponding hole in the cab floor. Gas vapors which are heavier than air are supposed to exit the cab through the hole. More on this later.

If you want to know how the vent works, take off the plate on the top surface. It is the same diameter of the sender and sort of looks like one, only there are no wire connections. It is held on to the tank by 5 bolts, same size as the sender. Under the cap, there is a large cork floating gasket that is supposed to seal the small vent holes when gas sloshes up. These connect with the top of the tube that goes through the full thickness of the tank and out the bottom. You might want to renew the sealing gasket when you put things back together, same as a sender gasket.

I found that when driving I got a good whiff of gasoline on occasion. Since the bottom of tank vent sits at least 1/2 inch above the exit hole in the floor of the cab I decided to extend the tube below the cab floor. That way the end of the tube would be below the cab floor and be in the wind under the cab. A short segment (1 1/2 inch) of 1/4 inch brake line was epoxied into the vent hole and that solved my problem. I think you get a Venturi effect on the end of the extended tube, which now sits in the wind stream, sort of like a crankcase breather.

1937 is the only year Chevrolet trucks had this arrangement, in conjunction with no external gas filler neck. You have to open the passenger door, pull up the right side of the split bench seat, open the filler bung and fill the tank from inside the cab. You should see the funny looks I get at the gas station with my '37 when it is time to fill 'er up. No wonder this lasted only one year.

Kent

Last edited by Lightholder's Dad; Mon Aug 02 2021 12:45 AM.

1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix
Re: ‘37 gas tank
37 GC #1419099 Mon Aug 02 2021 12:53 AM
Joined: Apr 2007
Posts: 889
L
'Bolter
Check out this previous post of mine with pictures of the top of the vent after it is disassembled.
https://www.stovebolt.com/ubbthread...mblem-on-37-chevy-parts.html#Post1325176
I was amazed that GM would bother stamping the cork floating gasket with a bowtie.
Kent


1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix
Re: ‘37 gas tank
37 GC #1419109 Mon Aug 02 2021 02:09 AM
Joined: Dec 2019
Posts: 177
3
37 GC Offline OP
'Bolter
I used to get some funny looks filling up the tank under the front hood of my '60 beetle and later with my '72 914 Porsche...so no worries. Thanks for the info as always. Glad there wasn't an impossible to find outrageously expensive vent system part! I did take the screws out and take a look at that floating gasket. Just hope its ok, replace the sealing gasket and slap it back together? My fuel gauge sender appears to be toast...the geared float doesnt want to move. I'll work through it. great suggestion about extending that vent. Is using steel brake line the recomended direction for a fuel line tank to fuel pump? the one that was crumpled underneath was copper


Larry
All you need in life is TIME, PATIENCE and MONEY.
If you are missing one component, you'll need an abundance of the others two.
Re: ‘37 gas tank
37 GC #1419112 Mon Aug 02 2021 02:45 AM
Joined: Apr 2007
Posts: 889
L
'Bolter
The usual vendors have a fuel shut off valve with accompanying pipe with pipe threads that fit into the tank. You then want a rubber flex hose between the valve and the hard line attached to the frame. 5/16 inch steel (brake) line is perfect for the hard line. In the flex hose I like to put a fuel filter to keep any junk in the tank from lodging in the fuel pump or carb. I use NAPA filter 3002, which is clear plastic so you can see if it needs changing. Regarding the sender Jim Carter has one; MEG124 is the part number.
Kent

Last edited by Lightholder's Dad; Mon Aug 02 2021 03:03 PM.

1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix
Re: ‘37 gas tank
37 GC #1419114 Mon Aug 02 2021 02:56 AM
Joined: Apr 2005
Posts: 2,837
C
'Bolter
On a 37 we done we got a rollover vent valve from Speedway. The small one fit in the same spot with little modification.


Evan
Re: ‘37 gas tank
37 GC #1419210 Tue Aug 03 2021 02:21 AM
Joined: Dec 2019
Posts: 177
3
37 GC Offline OP
'Bolter
Thanks Kent, will do. what is the advantage to the rollover vent? Coilover: I understand how the original worked, how does the roll over work in the "modified" spot?


Larry
All you need in life is TIME, PATIENCE and MONEY.
If you are missing one component, you'll need an abundance of the others two.

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