So i'm new to restoring vehicles, and it's been a long time since i've done any real work on one. I just bought a 78 F150 4x4 with a 351M and a C6. My fuel gauge does not work, and i have read that i need to try grounding the ground wire to the sending unit. Can anyone tell me what wire this is? I crawled underneath and saw a wire coming from the side of the tank and going to a subframe, i'm guessing this is it? Should I just disconnect it from the subframe and clean both sides off and reconnect it? Also, the only light in my instrument cluster that works is my right turn signal. Both signals work, but only the right light lights up. What should I check first for these? I pulled the cluster out and all of the bulbs were good, or at least looked that way, but i did notice that the printed circuit had been folded at some point and has a slight crease in it...could this be preventing my lights from working? And one last thing for now...i do not know the last time the rear tank was used, and neither does the person I bought it from...I haven't tried flipping the switch out of fear of gumming up the lines/carb, so I'm not certain it even works. Would I be best off just replacing the tank and sending unit rather than trying to clean it? Should I replace the lines to the rear tank as well? Thank you in advance to anyone with any advice! I GREATLY appreciate it!

 

ok. i have the same problem with the dash lights on my 76. idk what is causing it either. as for the fuel gauge, have you actually flipped the switch? you said you havent, and you have to for it to switch tanks and change the pick up.

 

No, i haven't flipped the switch...I don't know when the last time it was flipped either. I haven't flipped it because I am worried of what is in the tank, and i don't want to gum up the lines or the carb. That's why I'm trying to figure out if I should try to clean the tank out, or if I should just replace it and the sending unit/lines. If i should clean it out, i'm just curious how i can safely do that so that I don't screw something else up and make it not drivable, this needs to be my daily driver. I'd like to be able to use both tanks, but one is better than none.

 

Not sure if this will help but on one of my old projects the car sat for a long time and I just used asiphon hose and a claer glass container to check the condition of the gas in the tank. This was on a '66 Fairlane but pretty sure you should be able to get a siphon hose all the way down into the tank. I also recommend using a pump or blowing into the tank to pressurize a bit so the gas will flow out instead of tasting and breathing gas fumes. Good Luck.

I also only have half the lights working on my dash, right turn signal works but not left or any lights on left. Keep us posted with what you find. I will let you know if I find anything int he dash if I get up enough gumption to look.

 

Hey! reviving this thread from the dead, did you ever start using your rear tank, and if so, what did you do to make sure it didn't gum up the works? I have the same situation on my '75 SuperCab- rear tank hasn't been used since 1985 according to the detailed records from the PO (original owner), and I'm trying to figure out how to get it back to usable condition.

-Josh