[T3] Tony Adams: gas gauge

["Jim Adney" <jadney@vwtype3.org>]

A few weeks ago Tony Adams bought a good used gas gauge sender from 
me and was good enough to send me his old one after the new one was 
installed. Today i got around to opening it up and I thought that 
what I found was of general enough interest to post it to the list.

The center stem that the float rides up and down on was rusty and 
dirty such that the float was stuck in mid-travel. There was rust, 
dirt, and corrosion on everything. corrusion had interrupted the 
contact with ground so that the gauge did not have continuity.

The sensor wire and float were intact, however, so I cleaned them up 
and removed the rivet. I need to replace the rivet and I'll solder 
all the connections that I can to make sure that everything has good 
contact. I think that with a couple of hours work I can make it good 
again. It's not a living, just a labor of love, or as Peter said, I 
get to have all the fun.

Tony, if this came out of your gas tank you should be concerned about 
all the water that has been in there. The sensor is dated '69, so 
this car has the overflow hose that is always broken and lets water 
in (and gas out.) Whether you still have FI or not, you need to fix 
this before it is too late. I'm interested in whether this sensor 
actually came out of a running car or not. It was in the worst shape 
that I have ever seen.

Thanks for sending it back to me.

Everyone out there should take this to heart and, if your car is a 68-
73, get familiar with your overflow hose. It is IMPORTANT to fix 
this. If you're not sure what I'm talking about, park your car with 
the steering turned all the way to the right. Reach up behind the RF 
tire and find the fuel filler tube (~2.5" dia.) Feel behind that tube 
until you find a rubber hose branching off of it and running inboard; 
this is your overflow hose.

Once you know where it is, you need to look at it. Get a flashlight 
and shine it on the rubber hose. If you see an obviously broken hose, 
or a hose that has lots of small cracks in it, then you probably need 
a new one.

There are 2 versions of these: 68-72 with 1/4 turn (bayonette) gas 
cap uses 311 201 179A which I have in stock. 72-73 with screw gas cap 
uses 311 201 179C which is NLA. The changeover was mid year 72.

If you want to verify that your hose needs to be replaced, go to the 
gas station and top up the tank. Then look up inside the fender. If 
you see gas running down the inside of the wheel well, then you need 
to fix it. 

The gas that leaks out is not really the problem. Obviously you can 
fix that by just not filling the tank all the way up. The problem is 
that the RF tire throws dirt and water right up against there when 
you drive. An hour's drive in the rain can easily put a gallon of 
water in your tank through an overflow hose that still looks pretty 
good.

There is one more thing that you need to be aware of. These cars have 
a vent system for the gas tank. Its most common function is to let 
air in the tank to replace fuel as it is used. These vent systems are 
usually clogged up due to the steel lines that some of them used 
getting all rusted up inside. When the overflow hose is cracked, 
these cracks also serve as vents, so you never notice that there is a 
problem with the vent system, but when you fix the overflow hose, you 
now also need to at least check, and probably fix, the vent system.

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Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
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