General Earth Strap Dilemma

[BarryH]

Hi All,

Since taking ownership of the 500F, I wanted to replace the battery earth cable which is currently located under the bolt which anchors the left fuel tank strap. Result was the anchor bolt just spins. Upon investigation the nut in the footwell which is bolted to and which I expect should be welded to the body is not.

So the options I see are:-

1. Try and get into the footwell and tack weld a nut, but the concern is the metal there looks relatively thin so wouldn't want to blow a hole in the panel
2. Just Nut and bolt it with a captive Nut
3. Use a Rivnut through the existing hole

I would be appreciative of any comments if anyone has experienced the same or thinks I am missing the obvious. Let the voting begin

Thanks all

Barry

 

[the green vanper]

Hello,

I know nothing about restoring old cars, but I know good earth is essential in a car. Why don't you want to find a better place for the earth strap?

 

[BarryH]

Hi I haven't looked for an alternative place yet, I was concentrating on locating it to the position where it was originally located under the fuel tank strap. Unless of course if the earth strap was relocate to the current position before I got the car

 

[Pete O]

I wouldn't use a rivnut for the earth.

 

[BarryH]

I wouldn't use a rivnut for the earth.

Thanks Pete, I discounted the rivnut early on and did my impression of a contortionist and tack welded the nut in the footwell. Could only tack weld at 3 points but knew the importance of a good earth so hopefully thats remedied

Thanks again

Barry

 

[fiat500]

Hi I haven't looked for an alternative place yet, I was concentrating on locating it to the position where it was originally located under the fuel tank strap. Unless of course if the earth strap was relocate to the current position before I got the car

Hi Barry. I posted this yesterday but it didn't upload....a bit late now, but worth considering.? If you can replace the captive or welded nut with a simple nut and bolt, that will be fine for the security of the fuel tank. But I would revert to the original earthing point which is very close to the battery. Originally, a stubby cable was soldered or crimped into an eyelet tab which was then spot-welded to the body. If you're getting involved with welding in any case, that would be. a better option.
I can't find a current image of my car, so here's a skeletal image that shows what I mean.

 

[BarryH]

Hi Barry. I posted this yesterday but it didn't upload....a bit late now, but worth considering.? If you can replace the captive or welded nut with a simple nut and bolt, that will be fine for the security of the fuel tank. But I would revert to the original earthing point which is very close to the battery. Originally, a stubby cable was soldered or crimped into an eyelet tab which was then spot-welded to the body. If you're getting involved with welding in any case, that would be. a better option.
I can't find a current image of my car, so here's a skeletal image that shows what I mean.

Thanks - duly noted and may revisit further down the line, I take it that is the latest in air conditioning you have there

 

[fiat500]

Thanks - duly noted and may revisit further down the line, I take it that is the latest in air conditioning you have there

.....it is not the primary air inlet that found on the car when bought, but it was a useful one. I would say that the air-scoop that was masquerading as a floor, and the sensible absence of the full length of the passenger side roof and guttering made a more significant contribution to moderating the internal temperature of the car.

 

[the green vanper]

I can't find a current image of my car, so here's a skeletal image that shows what I mean.

That's definitely not a good earth... The earth point needs to be done on a clean steel, not on a rusted place. It will cause lots of issues like ignition, battery charging etc. Definitely less problematic on an old car than on the new ones, but still will cause some.

 

[fiat500]

That's definitely not a good earth... The earth point needs to be done on a clean steel, not on a rusted place. It will cause lots of issues like ignition, battery charging etc. Definitely less problematic on an old car than on the new ones, but still will cause some.

Chances are that when my car was originally found in that state, the steel at the battery box wasn't even continuous with the rest of the bodywork!
What I'm trying to show is that the original earthing point was only a few centimetres from the battery and not under a tank-strap bolt.

 

[Pete O]

Not everyone has access to a spot welder and the original earth would have been spot-welded to that panel before the panel became part of the car. A nut welded to the body as described will make an excellent earth, run a tap through the thread to clean out any paint after you paint where you've welded. That'll be less of a rust opening than the usual advice of scraping away some paint from a panel surface to put a bolt through. The distance from the earth point to the battery is not really an issue unless your cable is too light- consider the length of the positive cable, it's as long as the car.