I am almost afraid to ask this question but here it goes. If cork is left without moisture for 45 years or so can it lose it's ability to float? The reason I am asking is because on my 29, the gas gauge reads empty regardless of the amount of gas in the tank. Full or empty it is the same. The car sat in a barn for 45 years and the cork dried out. The gauge is is dependent on the cork to float when fluid is available and the gauge rises accordingly. The armature swings freely and without a hitch when moved manually out of the tank but not when it is in.
Hope this doesn't expose my ignorance.

Did you ever place the cork in a can of gas? Does it float?

The cork is covered with schlack when new to seal it.

Old cork always floats unless it is soaked up with gas.

Hello langer,
I'm not able to tell, from reading your post, that you verified the sending unit moved the fuel gauge needle, electrically, when you manually moved the float arm. By all means, change the cork float while it's accessible and check your wiring and ground connections. If your system works ok manually, but fails when installed in the fuel tank with fuel available, remove the float and bench check it's floatation ability. There may be another possibility that the float arm is unable to float due to improper installation positioning. If a 29 does not have an electric fuel gauge system, then that shows my ignorance.

Thanks for the information. You are right, the 29 is 100% manual and the cork and the gauge on the back of the tank is the only piece to the gauge. After I wrote this my nephew said, "take the cork off, drop it in a pail of gas and see if it floats." Felt kind of stupid over such an easy solution. I will do that tomorrow.

Don't be surprised if the cork does not float. I changed from cork to brass on my '28 which has a gauge the same as '29. I have found that the corks fairly quickly fill with gas if any alcohol is present.

I re-corked my float several yrears ago. I used new cork and shellacked it like original. The fix worked for about 3 years.
With the new gas, the shellack dissolves and exposes the raw cork and then it sinks.
Removing the gas tank is not that hard but it is something else to do when you really don't want to di it again.

To resolve any problems, I purchased new plastic floats from a Model A supplier. These are alcohol resistant, inexpensive and effective. 5 years and no problems.

I don't understand what happened because I took the gauge which includes the armature and the cork out of the tank. On my 29 this can be done by unscrewing the lid where the gauge is and it is not necessary to remove the tank. I then shellacked a new cork reinserted it into the tank and the gauge works with no problem. The interesting part is when I took the old cork off of the armature and placed it in liquid it also floated with no hesitancy. However I noticed when the old cork was being removed it had adhered to the armature and it would not turn freely which may or may not make a difference. The old cork was very brittle and crumbly. Having said all of that, I have not come to a reasonable understanding as to the why's and wherefores. I know the new cork makes the gauge work correctly and the old cork floated when put into liquid after it had been removed from the armature. Why the gauge would not work with the old cork will remain a mystery.

The old cork may float on it's own but doesn't have enough flotation to lift the arm on the guage as well.

Thanks. You probably hit the nail on the head. Happy THANKSGIVING.

Doesn't make any difference.