After sitting for 8-9 years the fuel system in the ‘65 Custom was in pretty poor shape. This is what I did...
NOTE: DO ANY OF THIS AT YOUR OWN RISK AND USE COMMON SENSE - I WILL NOT BE RESPONSIBLE FOR SOMEONE BLOWING THEMSELVES UP BECAUSE THEY DID NOT TAKE APPROPRIATE PRECAUTIONS!!!!
IF YOU DO ANY OF THIS YOU DO SO AT YOUR OWN RISK - SOME OF THE STEPS AND SOME OF THE MATERIALS ARE EXTREMELY HAZARDOUS!!!!
Initial Condition -
* Fuel lines rotten
* Fuel tank rusted (internal)
* Fuel Filler to Tank connection loose and gasket/o-ring no longer sealing properly
* Fuel Level sending unit badly rusted, float disintegrated
WHAT I DID-
Cleaning the Tank and System
* I pulled the entire system including the tank
* Took the tank to a local radiator shop to have it vatted (I checked a number of them but only a couple could accommodate the size) - they said that they would do it but when they saw it the refused saying that when they get "that much rust in them they are almost always too thin to be safe.
* Took the tank to the local car wash and pressure washed it repeatedly until water ran clear (well - almost).
* Took the tank home and put about 5 lbs of crushed granite in it. Spent about a half hour shaking the gravel around in the tank to break up any additional rust or crud.
* Back to the car wash for another pressure wash and then back home quickly to dry it out with compressed air and then fans. (note - take a big flashlight - it will really help in making sure that you have all the crud out of the tank.
* Sand blasted the surface rust off of the connecting surfaces for the filler tube and the sending unit
* Sand blasted the rust out of the filler tube
* Sand blasted the sending unit (note – this might not have been the best idea. I probably would have been better off using naval jelly or some other rust removal technique here as it took HOURS to get the sand out of the mechanical portion of the sending unit).
Testing the tank -
NOTE: - THIS IS ONE OF THE PLACES WHERE STUPIDITY CAN REALLY HURT YOU OR KILL YOU. BE VERY CAREFUL AND DON’T OVERPRESSURE THE TANK – YOU CAN TURN IT INTO A BOMB IF YOU ARE NOT CAREFUL AND CAN REALLY END UP HURTING YOURSELF!!! THINK ABOUT THE ENERGIES ASSOCIATED WITH 100 PSI OVER THE TOTAL SURFACE AREA OF YOUR FUEL TANK…
* Sealed the inlet with a HUGE rubber stop (I found mine at a marine supply store) and a strap lightly tightened around the tank holding the stop in place.
* Used a piece of fuel line and hose clamps to attach a compressed air source to the fuel outlet tube in the sending unit (you want to use something with a pressure gauge – I used an old low pressure tire filler unit that I rigged)
* Installed a new o-ring between the sending unit and the tank and block any additional lines in the sending unit.
* Installed the sending unit
* Stole my toddler’s wading pool and filled it with water to within a couple of inches of the top
* Locked the kids and dogs in the house
* VERY CAREFULLY pressurized the tank to about 2 psi
* Put the tank in the wading pool and rotated it repeatedly looking for bubbles. I found a few leaks around the inlet and the sending unit but nothing else.
Sealing the Tank -
READ AND FOLLOW THE PRECAUTIONS ON THE SEALANT SOLUTION THAT YOU BUY - WEAR A RESPIRATOR!!!
* I purchased a fuel tank sealant kit from Bill Hirsch Automotive (http://www.hirschauto.com/) . It was about $50.00 shipped and was well worth it compared to the price I would have paid for the same volume of sealant from the local motorcycle shop.
* Sealed the tank per the instructions and let it dry for a couple of extra days.
* I did not seal the sending unit (I probably should have done something but I did not want to gum up the mechanicals)
* Replaced all the rubber line with new from the local parts store
* Replaced the inline filter
* I could not find a new seal for the filler tube so I put a light coat of “Permatex® Form-A-Gasket® No. 2 Sealant” (supposedly fuel resistant) on the seal and reinstalled it.
* I was unable to locate a new sending unit float until I took the whole unit to the local dealer with a “legacy parts” department and found the one guy with a clue. I has called this same department and been told that there was no part available but that I could buy a whole new sending unit for $$$$$. When I took my unit down to confirm that the new one that I was going to buy was the right part I asked one more time. The guy asked me why I didn’t just buy a float ($#*^%*#&^$). Anyway – apparently there is a fairly standard brass cylindrical float for these and they just don’t cross reference properly all the time (lesson – when looking for obscure parts – ask a few people the same question a few different ways before giving up).
* Replaced the o-ring/seal under the sending unit and reinstalled the sending unit
* Reinstalled the tank
* Reinstalled the filler tube and covered the seam with the same Permatex® Form-A-Gasket® No. 2 Sealant.
* Reattached all lines to the fuel pump
* Added fuel carefully and confirmed function
A few months later I still have a working fuel system and no leaks. I have not pushed my luck and filled the tank to the top of the neck but I have had it 9/10th full and have no leaks at the filler neck due to sloshing etc. I will forget one of these days and top it off – then I will know for sure whether that seal is really working. I hope that this proves useful….