1937 Buick Fuel Sending Unit

[37 Buick Special]

Any folks out there that can provide me with info on how to remove a sending unit from a gas tank on a Special? Greatly appreciate any information.

Dave

[LAS VEGAS DAVE]

Lower the tank and remove the screws from the sending unit ring and remove it. Also disconnect the wire that goes to it.

[37 Buick Special]

So the tank has to be taken down (off)?

[Gary W]

This is how I did it:

1. Remove the gas filler neck and rubber fender grommet

2. Released the bayonet base wire (sending unit wire) in the trunk and pushed the wire through the hole and rested on top of the tank

3. Removed completely the filler neck support from the chassis

4. Disconnect the fuel supply line from the front of the tank.  Need a 9/16" and a 1/2" wrench

5. Remove the gas tank support straps using a 9/16" deep socket

6. Tank is now loose and ready to drop (If it has't already!)

7. By pushing the drivers side up and forward you can carefully turn the tank and it will come down

8. Sending unit is affixed with 6 machine screws and a gasket.

 

Have a great day!

Edited May 23, 2017 by Gary W (see edit history)

[MCHinson]

Gary is correct. The two things that you need to know if you don't already know is that, " Remove the gas filler neck" refers to the fact that the part of the gas filler neck that sticks through the fender has to be unscrewed from the bottom section of the gas filler neck before you can get the tank out and also that you have to jack the back of the car up about a foot or so from the floor to have enough room to turn the tank to get the tank out.  

[Gary W]

 

Removing a 1937 Buick Fuel Tank .....  Accessing the fuel tank sender unit:

 

This is how I did it:  (Same sequence with photos)

 

With the car still on the ground:

 

1. Drain the fuel tank into a suitable container by removing the 9/16" plug from the bottom of the tank. 

2. Once you have (or think you have) most of the gas out, replace the 9/16" plug lightly as more will come out as you turn the tank to drop it.

3. Remove the gas filler neck and rubber fender grommet. (Originally you would unscrew the "extension" that protrudes out the fender from the tank filler pipe.  My car's filler pipe was cut and the previous owner simply used a heavy duty hose and clamps to attach the two.)

4. Release the bayonet base wire (sending unit wire) in the trunk and pushed the wire through the hole and rest it on top of the tank

5. Remove completely the fill pipe support clamp from the chassis and the fill pipe and slide it off.

 

Jack the car up at least a foot, and securely set jack stands under the frame by the rear running board support irons.  Chock the front wheels.

 

6. Disconnect the fuel supply line from the front of the tank.  Need a 9/16" and a 1/2"  flare wrench

7. Remove the gas tank support straps using a 9/16" deep socket

8. Tank is now loose and ready to drop (If it has't already!)

9. By pushing the drivers side up and forward you can carefully turn the tank and it will come down.

10. There may be a dedicated ground wire attached to the base of the sending unit.  If not, you may consider adding one before re-installation.

11. Remove the sender wire from the sending unit.  It's a good time to check the end is soldered tight and the insulation/shrink wrap is good.

12. Sending unit is affixed with 5 machine screws and a gasket.

 

 

 

 

Remove the filler neck extension from the fuel tank fill pipe.  My car has this heavy hose and clamps.

Originally, the extension unscrewed from the fill pipe.

 

The extension can be pushed right out of the top of the fender.

 

 

Completely remove the fuel tank fill pipe support clamp from the frame and the pipe.  Slide it off.

Here's the frame connection.

 

 

Same clamp, here's the fill pipe connection.

 

 

This is the bayonet base sender wire that comes through the bottom of the trunk.

(out of sequence)

 

 

Disconnection the fuel feed tube.  A 9/16" wrench at the tank and a 1/2" flare wrench at the flared connection.

 

 

And once all the external parts are off and released, use a 9/16" deep socket to loosen these nuts.

The support irons will come down, releasing the tank.

 

 

Use the deep socket to reach to the bottom of the "T" bolt inside the support strap.

 

 

A couple of twists and turns and the tank will drop out.

That's the sender wire from the trunk hanging off the sending unit.

 

 

Remove the five screws and carefully pull up and remove the sender.

Tip it 90 degrees to get the float out. 

On reinstall, consider attaching a dedicated ground wire to one of the mounting screws.

 

 

Gary

Edited November 29, 2020 by Gary W
Label the photos to go along with the text. (see edit history)

[Ben Bruce aka First Born]

If you replace the sending unit with an after-market one, BEWARE. I have seen none that re-connect to the gas line directly. All use a rubber tubing. Therefore the ground is lost. I run a ground wire from one of the attaching screws to someplace on the body or frame.

 

  Ben

[37 Buick Special]

You guys are First Class, especially you Gary W for posting all the photos. Picture is worth a 1000 words. You all make dealing with this Buick (for a newbie Buick owner) much less stressful. Guess I had better be sure it is the sending unit before I go to all the trouble and huge effort to pull the tank.

Thanks again!

[Gary W]

You are very welcome!   I bought my first Buick just over 3 months ago and for sure was a "newbie".  But I found very quickly that with the help on this forum, the Buick Shop Manual(s), and a couple knowledgeable friends, your learning curve is very steep!  Honestly, you'll have the tank out in about 30 minutes tops!  It's not a tough job.

Good Luck and have a great day!

[MCHinson]

Gary,

 

It looks like someone cut your fuel filler pipe in the past. The original one looks like it is one piece and will have you scratching your head until you figure out that you have to unscrew the top section that sticks through the fender from the lower section of the fuel filler pipe. 

[37 Buick Special]

Gary,

You are about the same degree of newbie as I am. 4 months for me. A tough car to work on for sure but as you say shop manuals, internet, this forum and a friend sure helps a lot.

Thanks and regards,

Dave

[Jim Nelson]

If you are having fuel levels problems, pray it's not a bad sender.  In by '38'' coupe, it began to stick. I ran out of gas but the gage said I had 1/4 tank.  The replace,ent units are function match BUT, the float is not in the center of the tank.  The float now points.to the drivers side.  Thus, it has the gage moving around a bunch.  It will only read correctly (sorta) when you are stopped.  Plus, the gage will not accurately show the l4vel.  Mine now has about 5 gallons remaining when it registers 'empty'.  So you will have to recalibrate your eye's and brain to figure how much gas is in the tank.. For me, I am most concerned about what the gage shows when I have about 3 gallons left.  I also want to know what the gage says when I have about 1/4 tank.  That is my 'got to find a ethanol free station and gas up.  My '38' runs so much better with real gas rather than the crap gas the government sells.  JMHO. I have always found gas on my trips in the SE.  Tons of places have good real gas but the further north you go the fewer places have it.

[Larry Schramm]

On ‎5‎/‎20‎/‎2017 at 8:53 PM, Jim Nelson said:

If you are having fuel levels problems, pray it's not a bad sender.  In by '38'' coupe, it began to stick. I ran out of gas but the gage said I had 1/4 tank.  The replace,ent units are function match BUT, the float is not in the center of the tank.  The float now points.to the drivers side.  Thus, it has the gage moving around a bunch.  It will only read correctly (sorta) when you are stopped.  Plus, the gage will not accurately show the l4vel.  Mine now has about 5 gallons remaining when it registers 'empty'.  So you will have to recalibrate your eye's and brain to figure how much gas is in the tank.. For me, I am most concerned about what the gage shows when I have about 3 gallons left.  I also want to know what the gage says when I have about 1/4 tank.  That is my 'got to find a ethanol free station and gas up.  My '38' runs so much better with real gas rather than the crap gas the government sells.  JMHO. I have always found gas on my trips in the SE.  Tons of places have good real gas but the further north you go the fewer places have it.

 

If you think the gas is bad going north, try going to the corn states Iowa & Nebraska.  Filling up in those states I lost about1/3 of the miles / gallon that I had on the rest of my trip last week.

Edited May 28, 2017 by Larry Schramm (see edit history)

[Bloo]

I'm not sure that getting the sender back to the middle of the tank would be enough. These are a balanced coil type fuel gauge. They respond instantly to any input from the sender, unlike the thermal gauges you might find on a much newer car. 

 

The original sending units have a cork brake to minimize movement. Sometimes it takes a few good bumps to change the reading after filling up.

 

They are a 0-30 ohm system, with 0 ohms at the empty end of the scale. The implication is that the grounds at both the gauge and the sender have to be perfect, or you will never get the gauge all the way to empty. The gauge wiring has to be perfect too.

 

I would suggest finding someone to rebuild the original sender.

[Matt Harwood]

On 2/11/2017 at 7:42 AM, Gary W said:

Hopefully these come through in proper sequence:

 

 

Now that is a how-to post! Nice!

[timb07052]

On 2/11/2017 at 2:07 AM, LAS VEGAS DAVE said:

Lower the tank and remove the screws from the sending unit ring and remove it. Also disconnect the wire that goes to it.

Does anyone know where to get a new sending unit or a rebuild for a 37 46C? Just took mine ut and its not looking too good.

 

Thanks!

[Gary W]

Run some simple diagnostics on it while it's still in the car.  I submitted a reply through my blog before I noticed this:

 

I sent my dash gauge cluster and my sender to Bobs Speedometer in Howell, MI.

 

 

 

For a good understanding of the gauge and some diagnostics, read the following starting with "I ran out of gas"....  There are a bunch of good guys on here that gave me great advice:

 

 

Hope it helps!

Gary