Float Soldering How-(NOT)-To.

[soxplayer]

I have always read that you can often repair a leaking brass float and get you carburetor on the road. Recently I got a brand new fuel tank sending unit from a good supplier, The sending unit worked perfectly for 3 weeks and then the gauge went to empty on a full tank. I removed the float from the sending unit and it sank in a pail of water. I decided to try and fix the float since it would allow me to put the truck right back out on the road. The float on a 67 is about the size and shape of a D cell battery and is made of two matching brass cup shaped assemblies that are soldered together. The shape of the float will allow it to spin like a top in the blast of a heat gun unless the airflow is direct onto the end of one of the cups. If you apply two much heat it is possible for the main solder joint to melt and the two halve of the float will separate (see below for details).

Now the disclaimer: You should not rely on the following directions to repair a float as a complete guide to float repair. In fact, you shouldn't try to repair your float at all... Read on and find out why.

Step 1) You must remove the gasoline that has leaked into the float. As you will see in later steps, gasoline is quite flammable and has a lot of chemical energy that must not be released by combustion even in small amounts in your shop.

Step 2) Get a heat gun and place the float in the airstream of the gun. Do this outside in a well ventilated area away from any structures or vehicles you value. Extinguish all open and closed flames at this point and put out all smoking material. You might want to find and check your fire extinguisher.

Step 3) As the float heats up, the gasoline will begin to boil inside the float and force its way out of through the leak. This is handy for identifying the repair site.

Step 4) When the gasoline seems to have been driven from the float assembly, allow it to cool. Test the float by floating it in the pail of water with the leaky side up. It should ride well out of the water or it still has gasoline inside. If you are no absolutely sure the float is empty, go back to step 2)

Step 5) Clean the area of the repair with sandpaper to prepare it for soldering, but only if you are SURE there is no fuel left inside the float.

Step 6) Now that you are SURE there is no more fuel in the float, reheat the float with the heat gun. As the float is warming, examine the leak to make sure that no fuel vapor is escaping from the float. If necessary, return to step 2).

The next few steps will be performed quickly so it might be best to commit them to memory because you will not have time to consult the instructions during the following procedure.

Step *) Now that the float has been heated and you are REALLY SURE that no fuel remain in side the float, begin heating the repair site with a propane torch in preparation to flow solder into the leak.

Step **) As the vapor that is still escaping from the float catches fire...

Step ***) Quickly remove the heat gun from the area in order to avoid fanning the flame.

Step ****) Extinguish the torch and remove it from the area as well.

Step *****) Notice how the flame has superheated the float and now the fuel inside the 'empty' float is forcing its way out of the float. Notice how this fuel imparts a spinning motion to the float like one of those spinning fire crackers from the Fourth of July. This spinning motion is normal, as is the panic you feel as you dive behind the house or vehicle you sought to protect in Step 2) (At this point you will not remember step 2 but, assuming all works out well you will want to congratulate yourself for this act of foresight when the repair is complete.)

Step ******) As the fuel float accelerates past 50 or 60 RPM you may detect that the gasoline flame powered nozzle that is imparting the rotation to the float is losing some energy and you begin to believe the gasoline powered firework will burn itself out.

Step A) (You will have lost count at this point so it might be time to start over using the alphabet instead) As the float begin to slow down and the flame looses some of its peak brightness …

Step!) The solder joint holding the two halve of the float together will reach its melting point.

Step !!) The two halves will fly away from each other to parts unknown but possibly towards the items you thought of protecting in Step 2) (Remember step 2)? I don't right now as my heart rate is off-scale and my ears are ringing from the sound of the two halves separating. (You might want to look around your yard to see if part of my float made it over to your place, I can guarantee that neither half is on my property.)

Step ?) Slowly realize what has happened and take stock of any damage.

Step ?!?!?) Try to explain to your wife what has happened now that she has run outside to she if she needs to call an ambulance, or worse.

Finally,

Go back in the house.

Order a new float.

Wait for delivery.

Oh, by the way if anyone tells you you can skip these steps by simply heating the float with the torch to drive out the fuel, I recommend you seriously consider avoiding all of this individual's advice in the future,

P.S. If you find a half of a fuel float outside in your yard: I don't want it back. Perhaps you could recycle the brass.