1935 Buick Series 40 Instrument Cluster Removal

[AussieTim]

Hi All,

 

Just after some advice on removing the instrument cluster from my 1935 Buick Series 40:

 

1) The temperature gauge has a capillary tube connecting it to a bulb in the engine water jacket.  Can the capillary tube be removed from the back of the gauge or does the gauge need to be removed with the entire capillary tube and bulb attached ?

 

2) The oil pressure gauge looks as though it has a tube nut on the back and a fine copper tube connecting it to the engine oil system.  Can I just undo the tube nut and pull the tube out of the back of the gauge ?

 

Many thanks, Tim

[Rock10]

1) No. The temperature line is filled with a gas or liquid. Has to stay together.

2) Yes. It's a tubing connection. Just be very careful. And oil may drip out when you take it out.

[AussieTim]

Thank you @Rock10.  That's very helpful.

 

Do I need to lower the coolant level before removing the capillary tube fitting from the engine ?

[Rock10]

1 hour ago, AussieTim said:

Thank you @Rock10.  That's very helpful.

 

Do I need to lower the coolant level before removing the capillary tube fitting from the engine ?

Yes, but removing the tube from the head can be a difficult problem. Search the forum for examples. You probably have enough slack in the tube to pull the dash out enough to remove the temp gauge. I'm sure other members have more info.

[1939_Buick]

The tube goes into a bulb which goes into the head. (all sealed)

That bulb can be hard to get out with out breaking. Be gentle.

The 1st image is generic AC (GM) but typical. 2nd & 3rd are for a 1939

Edited May 18, 2021 by 1939_Buick (see edit history)

[AussieTim]

Thanks again @Rock10and @1939_Buick.

 

I can see that it would be very easy to damage it, especially as it is likely to be corroded.

 

The reason for my question is that i want to fix the fuel gauge which has not worked since i have owned the car.  It always shows empty.  I tested the rest of the circuit and it looks OK (gives about 0 to 30 ohms of resistance at the gauge depending on fuel level).  I then found that the positive power wire had been disconnected at the gauge at some point in the car's past.  However, reconnecting it did not bring the gauge to life.  I'm hoping that the needle is just stuck due to not having moved for many, many years.  Otherwise perhaps there is an open circuit somewhere inside the gauge.

[50jetback]

Try running a ground wire from one of the screws on the sender unit to the chassis.

[Bloo]

I agree.

 

And if that doesn't fix it, once you are in the dash and have the gauge out, look at how the gauge grounds. There is some particular spot on it that grounds to the gauge housing. As I recall it is not as obvious as you would think. Make sure that ground connection is OK. Make sure the gauge housing grounds to the dash.

 

Since there were wires disconnected, make sure the hot wire is connected to the correct post.

 

 

[Kenneth Carr]

Just a caution: if the temperature gauge is working I suggest you avoid removing the sender from the block. It will likely break if you do that. Then you have to find a new one to install or have the broken one repaired. Also, as mentioned above you cannot open the capillary tube from the dash end without destroying the seal and releasing gas. Just remove the whole gauge if it is in the way.

[Rock10]

I believe from previous posts that the gauge needles are all between 2 pieces of glass and care must be taken not to bend them when removing the gauge. On the gas gauge, power goes to the lower post and the sender goes to the top post. Grounding the sender wire or post should send the needle to empty. With power to the gauge and the sender disconnected, the needle should peg at the top. Is yours still 6 volts?