51 Series 62 Gas guage ground

[wrench]

I am curious about the return path for the gas guage level sending unit. I have removed the old tank and will be installing a replacement tank while hopefully re-using the original sender (if it bench checks good...) I intend to lay in some paint in the fuel tank recess area and the tank itself prior to re-assembly. I do not want the paint to affect the ground.

My question is what provides the ground return path for the sender? The straps and tank have tar paper strips (to dampen vibration?) that would interfere with the return path. The only thing I can think of is the fuel line/clamps, but I do not know if they are isolated for vibration as well.

Thanks.

[Dave Shepherd]

General practice in my shop is to attach a ground from the lip of the tank to the chassis, especially with 6v cars.

[wrench]

General practice in my shop is to attach a ground from the lip of the tank to the chassis, especially with 6v cars.

Thanks for the prompt reply, Dave. I am still running 6v. your gp sounds like a plan. But still curious what the original design called for...

Jim

[Caddy Wizard]

I believe the T-bolts tended to scrape a little against the edge of the flange of the tank and provided a ground path there.  I don't think the tanks were painted -- I think they were lightly zinc  plated, so the edge of the tank could provide a proper ground.  Even if they were painted, the T-bolt would have scraped off a smidge of paint right on that flange edge and grounded there.


Art

[R Sotardi #11719]

Just did that two years ago with a new tank on my 50. As Art said the tank hooks provide the clear ground, but mine were coated, by me, to prevent rust... to my dismay. As Dave said fasten a wire on the tank to a good chassis location. What I did was to crimp a  circle terminal on each end of a 1 foot piece of #14 wire. Drilled a small hole in the sheet metal area of the rear compartment. Removed one sender screw( the one at 2 o'clock), pushed it through the terminal and replaced it back with a dab of tank sealant on the threads. Then I fastened the other end with a self tapping sheet metal screw into the predrilled hole in the trunk area hole. Works great for a coupe of years  now. Ron

[wrench]

Just did that two years ago with a new tank on my 50. As Art said the tank hooks provide the clear ground, but mine were coated, by me, to prevent rust... to my dismay. As Dave said fasten a wire on the tank to a good chassis location. What I did was to crimp a  circle terminal on each end of a 1 foot piece of #14 wire. Drilled a small hole in the sheet metal area of the rear compartment. Removed one sender screw( the one at 2 o'clock), pushed it through the terminal and replaced it back with a dab of tank sealant on the threads. Then I fastened the other end with a self tapping sheet metal screw into the predrilled hole in the trunk area hole. Works great for a coupe of years  now. Ron

Thank you, gentlemen. I agree about adding the jumper and using one of the sender screws to do so. I will also verify the contact of the hooks to see if that path still has integrity.

Jim