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LAS VEGAS DAVE

GAS TANK SENDER FIXED

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Today I pulled the gas gauge sending unit from our car and made a minor bend in it. The gauge now reads from all the way from the full line right down to the empty line. My gas tank holds 

just under 17 gallons. I drained it with the plug on the bottom and read the gauge and then added two gallons at a time to see how the gauge worked. I am wondering if this is a 38 tank 

since it does not hold eighteen gallons as the book called for. It looks like the tank was replaced with a brand new one when it was in the Lewis Jenkins museum and I guess its possible that he used a different one. He was a primarily a 1940 Buick collector but he had a few other years as well if the car was exceptional. He had mechanics to keep all he cars like he wanted and in those days it was possible to get a new 38 tank if he wanted one. This one seems to fit perfect so I guess I will never be sure. In any case it is nice to have the gauge working correctly, it used to bug me. 

Edited by LAS VEGAS DAVE
rewording (see edit history)

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I have to drop my tank to get the sending unit out.  Could you do it while the tank was still in the car?

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  Many years ago I removed my tank from my 37 with the filler attached (they don't all seem to unscrew towards the top as mine was soldered).  I had to jack the car way up in the air and do a lot of contortions with the tank to get it in and out and that was only after I removed the right rear fender.

 

Carl

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Dave, is your gauge original?  Or, aftermarket?  Also, if your tank is a '38, it would have a rigid filler on the driver's side.  Wasn't the '37 filler different?

 

My aftermarket sending unit reads reasonably accurately, but bounces like crazy as the gas sloshes around.  It looks like the original has a little washer that dampens the device, while the aftermarket has no such feature.

 

Is this a common experience out there?  Any fixes for this? 

 

Jeff

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My '38 Roadmaster sloshed around a lot too. I had the original sender with the washer.

Unfortunately, recently it has been giving problems.

I took the original sender out, bench tested it and it works OK there - the jury is still out on that.

 

I did manage to get the sender out without completely removing the tank, but it is different from the '37's

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Yes, theres a cork washer that acts as a brake.

t2RmH0c.jpg

 

There is also a baffle in the tank around the sending unit to slow the sloshing (at least on 37 Roadmaster).

 

The balanced coil design of the gauge causes it to respond instantly to input from the sender. With an aftermarket sender I would expect a lot of waving around.

 

Also,  the brake in the picture wont work correctly as is. There is a notch in the back side. The little tab you see should be captured in the notch.

Edited by Bloo (see edit history)

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If I were re-conditioning one of the original types, I would try to see if there is a way to replace that cork washer.

 

I don't see any way to get this dampening function from the aftermarket type.

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5 hours ago, jeff said:

Dave, is your gauge original?  Or, aftermarket?  Also, if your tank is a '38, it would have a rigid filler on the driver's side.  Wasn't the '37 filler different?

 

My aftermarket sending unit reads reasonably accurately, but bounces like crazy as the gas sloshes around.  It looks like the original has a little washer that dampens the device, while the aftermarket has no such feature.

 

Is this a common experience out there?  Any fixes for this? 

 

Jeff

 

Jeff, my 38 gauge is original. I had my original sending unit rebuilt by someone out of HEMMINGS.  My tank has a drivers side fill spout and it is fixed to the tank. I was told a 37 is supposedly the same tank with the filler on the opposite side, is the filler on a 37 on the passenger side?

Edited by LAS VEGAS DAVE (see edit history)

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Yes. ‘37 fills on the passenger side. There is a large rubber hose  that connects the fuel fill pipe that protrudes through the fender with the tank. 

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The 38 has no rubber hose and the car has to up fairly high to maneuver the tank out because the spout is fixed to the tank.  Keep in mind that I am not sure my tank is actually original since it holds about 16 plus gallons, definitely not 18. I drained it completely with the plug on the bottom of the tank, I'm pretty sure there wasn't 2 gallons still in the tank. When my gauge first hits empty there is still two gallons in the tank.

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 My 1937 Special doesn't have a rubber hose section either and neither did the 37's I parted out. It is my opinion over the years to simplify removal and installation some people cut the filler and spliced them back together with rubber hose.

 

Carl

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Both my '38's have their original tanks and gettin them out is a royal PITA.  Getting the fill tube snaked out of between the body and frame is a job.

 

Interesting about the cork "brake" neither of my senders had that - brobably rotted away.

DSC_6755.JPG

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Regarding the tank filler neck (the filler actually attached to the tank) and the short length of filler pipe at the upper end.  There isn't really a "length" of hose section.  When the upper section is installed, it pretty much meets the tank filler neck.  The hose is clamped to keep it all tight and of course stopping it from leaking.

 

When I dropped my tank, I went to the Buick manual for instructions:  (Removal of Fuel Tank)

 

5a347c8e00915_Scan1.thumb.jpeg.1a555839b232ac72bfad52c931105e17.jpeg

The manual discusses removing the "short length of filler pipe at the upper end"

 

 

5a2e9ce17f516_DSC_4318(1).thumb.JPG.6dbe235059dc2cfeffebee9f3705bd0a.JPG.0b48a6c7474cb198d2362369f1530560.JPG

That's how my '37 Special is made.  The upper filler pipe is nicely made with a rolled edge.  Not cut off the tank filler.

I wonder if Buick changed the design with the '37 Special "on the fly"?

 

Gary

 

 

 

 

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Gary,

 

Your filler has been altered. The original was all metal. The piece that goes through the fender on a 1937 is actually screwed onto the lower section. On an original 1937 you can't remove the tank from the car with the right rear fender on the car unless you unscrew the end of the filler pipe from the rest of the tank. I suspect someone in the past did not know it was threaded and cut it. They then apparently simply installed a rubber hose to reinstall it. 

 

Page 8 of the attached Torque Tube II explains the 1937 tank removal procedure.

VOL 9 No 4 JULY-AUG 2016.pdf

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When I read "Remove the short length of filler pipe at the upper end",  my car had the hose and the clamps so I figured....  OK, Simple!

Loosen the clamps and off it came!  I had no idea until now that the short length is supposed to screw into the tank filler pipe.

 

Learn something new everyday around here!

Thanks

Gary

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1 hour ago, DonMicheletti said:

Both my '38's have their original tanks and gettin them out is a royal PITA.  Getting the fill tube snaked out of between the body and frame is a job.

 

Interesting about the cork "brake" neither of my senders had that - brobably rotted away.

DSC_6755.JPG

 

I didn't have the cork brake either. I didn't have to take my tank completely out of the car yesterday but I remember when I did and it was a PITA but it sounds easier than the 37 tanks.

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