View Full Version : Fuel System: Fuel sending unit

03-21-2015, 07:21 PM
I have installed a new fuel sending unit in my m16 truck . It has a cork float which had some kind of clear coating on it . Being new old stock the coating may have deteriated . Should i recoat it and with what?

03-21-2015, 09:08 PM
The clear coat was to keep the float from becoming waterlogged (gaslogged) and sinking. Modern fuel can dissolve the coating. You can replace the cork float with a brass float available at your FLAPS. Having said that I am driving several cars that have the original cork float still working fine so far.

03-21-2015, 09:47 PM
The original cork floats were coated with shellac, which is an alcohol based product. It worked fine until alcohol was added to gasoline. There are modern alcohol resistant coatings and coated cork floats that can be used to eliminate this problem.

03-21-2015, 10:39 PM
I think my new cork float had shellac on it. I bought a spray can of shellac and gave it an additional coat. It's doing fine after 10 years and many of those years I had the ethanol crap gas in the tank. If I had to replace one today I'd go the the junk yard and buy a float off a sending unit that iss made of the new neoprene or what ever the stuff is. It's usually black, but I've also seen brown.

03-21-2015, 11:22 PM
Do you have to drop the gas tank ,a ways to get the sending unit out ? One guy use model airplane dope on the float ,and says it works fine.I have a 55 president 2 door ,and wonder if you have to drop the tank to get the sending unit out?

03-21-2015, 11:52 PM
i can't say for sure on the '55, but i think you can get to it from the top - thru the trunk "floor".

03-22-2015, 07:10 AM
Thanks for the replies . I guess i will leave it alone until it gas logs and sinks . Then replace it . As for access , i had to drop the tank to get to it . Quiet a job . The tank was in sad shape . Had to cut the top out and replace the metal in the top as it was paper thin and thousands of holes . After bead blasting the inside and putting new metal on the top , i used por 15 tank liner . I cut an access hole from the top under the seat to make access easy .

03-22-2015, 09:40 AM
Getting ready to install a Stewart Warner 114876 in my Lark, Cork was gas logged and always reading 1/4 tank. Tested sending unit and when @ 1/2 mark or above OHMs would go to 0. So it is dead meat. $34 at Summit