Bringing back to life

[Ohlordyitsa40]

So, I’m new to this group and to pre war Buicks. My wife had bought a 1940 Buick special, and I think it’s mod 41, I’m having a few questions and I hope to find someone with advice here to help. Issues include wiper vacuum , fuel gauge and a mystery wire attached to the steering column under the hood in the engine compartment that goes nowhere. Any help would be appreciated. 

[Dave39MD]

Welcome and congratulations on the 40. In many cases the wire coming out of the steering column is the horn ground wire which sounds the horn when the button is pressed. I would try and find an owners guide and shop manual as soon as you can. The 1942 shop manual is also very helpful for past models.

 

Dave

[Oregon Desert model 45]

The fuel gauge requires a good ground to the gas tank and over time rust will degrade the bonding.   Also over time the sending unit inside the tank can get cruddy from gasoline varnish.  New replacement sending units should be available.  Drop the gas tank and see what is going on, and before reinstalling make sure there is a bonding path between tank and body. 

Vacuum wiper motors can get stuck from old hard grease and may need to be cleaned out or rebuilt. Also the vacuum tubing gets old and brittle and could be leaking. 

If there is any more wiring on the car that has cracked or missing insulation like that horn wire you should consider replacing it. 

Edited April 18, 2023 by Oregon Desert model 45
edit (see edit history)

[1939_Buick]

Welcome to the world of Buick straight 8's

 

Download the 1942 Buick shop manual for free. All of it section by section.

Or click the pdf link to pay.

http://www.oldcarmanualproject.com/manuals/Buick/1942/Shop Manual/

It is very comprehensive and has information that can be used with all straight 8’s.

It has more information than was included in older “Shop Manuals” before 1942

 

We like photos

[Ohlordyitsa40]

Outstanding. Thank you all for the help. This is proving to be a great group. I’m some what computer challenged, so I’m still learning to use the chats. Lol

[EmTee]

Post a picture of the cowl tag as that specifies exactly what you have.  A picture of the engine number would also be helpful to confirm what you have.

[neil morse]

16 hours ago, Dave39MD said:

In many cases the wire coming out of the steering column is the horn ground wire which sounds the horn when the button is pressed.

The wire attached to the steering column is actually the "hot" wire going to the horn button.  As Oregon Desert said, you should seriously consider replacing your wiring if the condition of that horn wire is typical of the rest of the wiring in the car.  I ended up putting a new harness from the dash forward on my '41 Super because the old wires were in really bad shape and it was not safe.

 

Here's a link to the part of my "Me and My Buick" thread where I show how I repaired my fuel gauge.  (Click on the arrow in the upper right hand corner to get to the post where the fuel gauge discussion starts.)  There some other issues discussed in my thread that might be helpful to you.  Welcome to the forums!

 

 

[Ben Bruce aka First Born]

Neil,  I am confused.  You say the wire coming from the steering column is the hot wire.  Would not that  require TWO wires?  If it is hot, where does the power to the horn button come from?

 

  On my 1950, and most [ all?] cars I have owned, that wire is a ground for the horn relay.  I thought!

 

Ben

[Bloo]

9 minutes ago, Ben Bruce aka First Born said:

On my 1950, and most [ all?] cars I have owned, that wire is a ground for the horn relay.  I thought!

Correct. But, to be fair, it will test "hot" with a meter when not honking, and that causes confusion now and then in threads like this one.

 

Edited April 19, 2023 by Bloo (see edit history)

[neil morse]

What Bloo said.  My understanding of electricity is somewhat rudimentary, so I should learn when to keep quiet.  I thought that the wire going up the steering column was "hot," and that hitting the horn rim causes a ground that completes the circuit.  (Like the interior lights, for example.)  So you may ignore my comments about the horn and carry on!

[Bloo]

No what you said is pretty much true.... just a tiny bit misleading. It is the ground, no doubt about that, but it measures hot until you ground it. This came up about a week ago in a Lincoln thread, and my response was kind of long, so I'm going to cut and paste.

 

Quote

There would be voltage, but not in the way you might think. An open ground will show the whole supply voltage when measured with a voltmeter. There just wouldn't be a lot of current available.

It helps to think of the open spot in the circuit as a resistor. You can't really do math on infinity, but think of it as something crazy high like 99 billion ohms. The resistance of the horn relay coil is dwarfed by comparison, and an overwhelming majority of the voltage gets dropped across the open part of the circuit, the 99 billion ohm resistor. The drop across the relay coil is so miniscule, you wont even notice it. All of the supply voltage will appear on your meter.

Now when you honk the horn, by shorting the contact, that 99 billion ohm resistor becomes 0 ohms. Well not quite 0 ohms because that is impossible, No connection is quite perfect. It is extremely close to zero though, maybe 0.001 ohms or something like that. Now the coil of the horn relay is the highest resistance in the circuit, and an overwhelming majority of the supply voltage gets dropped across it. The relay pulls in and the horn honks.

It's the same reason you can measure voltage on the ground terminal of an ignition coil when the points are open.

 

 

 

Edited April 19, 2023 by Bloo (see edit history)