Model A electrical

C

Cockshutt Kid

Member
Good evening guy's. I am planning on taking my 31 Tudor apart this winter for paint. I know that most electrical problems on 6 volt cars and tractors are usually related to poor grounds. I have read several posts here that refer to running separate ground wires and some that discuss using star washers to ensure a ground. My first reaction is to carefully sand all the new paint off of the mating parts such as headlight bar and fender mounting area and tail light mount and fender mounting area to ensure good contact. But, how do you deal with the rust that is bound to attack these surfaces? Would dielectic grease work in preventing rust and still provide a good electric contact.? What about between the different body pieces and the frame? Am I worrying too much? Should I take precautions or just stick it back together and deal with whatever doesn't work. Opinions are appreciated.
 
well headlights ive heard of people being crafty and running a wire thru the conduit. dielectric grease is supposed to keep water out and act as a crude insulator, they do make contact grease that has metal particles in it to ensure the best ground possible and still is grease so it wont rust.

I HATE star washers, they create more problems and invite little crevices for water to sit and rust.

Id say your best bet is cleaning them good and shiney and get some conductive grease and just put a little blob or two - remember it squishes out and can get rather messy.

Run a thick ground from the frame to the trans to engine bolt to get the best engine ground. clean paint to bare metal, attach grounds with conductive grease, then paint over everything.

not much reason for the body sheetmetal to be grounded. with all the contact points it has its bound to find one somewhere.
 
When I restore my car I will simply put it together and see if it grounds OK. I put grease on all the threads of bolts and on the lock washers. If I had a poor ground I will loosen the nut and retighten it. I don't like bare metal that can rust. So far my unrestored Tudor and Phaeton have had no ground problems.

I saw a generator on a car that had considerable rust have a ground problem, and it cooked the generator, but so far I haven't worked on a car with a ground problem due to paint. Here are the only parts that need to be grounded: battery ground, headlamps, taillight, generator, distributor, horn button, and starter. And you can add body to frame.
 
Really? I'm electricaly clueless, but always thought full contact with the terminal against the BARE steel frame or electrical fixture was the goal. Bob
1930 coupe said:
Unless you put on extra thick paint, the nuts and bolts will dig into the metal and make contact. With normal paint you should not have a problem.
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A recent article in The Electrical Connection suggest not to use star washers. German wave washers or conical washers. You want the most surface contact you can get...Grounds are good, particularly from frame to engine. My car is as it was designed, seems ok. It certainly doesn't hurt.
 
I had headlight issues until I...

Gutted out the original style but repop connectors and soldered the wires together (after removing the bullet ends) Shrink tubing on the outside as insulation. With the conduit in place you can't tell I've monkeyed with it.

Soldered a small wire on the outside of the bayonet sockets (both) and ran the combined wire down in the conduit. Without the original style but repop connectors there is plenty of room for an additional 16 ga. wire. This wire exits the conduit inside the radiator shell and is secreted (shhhh!) inside the edge of the radiator shell and follows it down to the frame. Wire then grounded to the frame at the back edge of the cavity in the front crossmember.

You almost can't see the modifications unless you know where to look.

Joe K
 
On a recent tour, my caravan-mates told me my left rear tail/brake/turn signal was VERY dim. I had recently had the left rear fender repainted. (Don't ask.) We removed the tail light bracket from the fender, scraped the back side of the bolt heads and wire brushed the nuts and bolts, scraped the inside perimeter of the holes where the bolts go through the bracket, scraped the backside of the fender, scraped the perimeter of the hole in the backing plate, and added lock washers between the plate and the back side of the fender, and tightened it all down. That solved it.

All this to say, I suggest you put it back together with clean bolts and perhaps a little scraping around the bolt holes for the tail lights, the headlight bar, and the headlights. Nothing major is required, just a few minutes of preparing a small area around the bolt holes.
 
SeaSlugs said:
well headlights ive heard of people being crafty and running a wire thru the conduit. dielectric grease is supposed to keep water out and act as a crude insulator, they do make contact grease that has metal particles in it to ensure the best ground possible and still is grease so it wont rust.

I HATE star washers, they create more problems and invite little crevices for water to sit and rust.

Id say your best bet is cleaning them good and shiney and get some conductive grease and just put a little blob or two - remember it squishes out and can get rather messy.

Run a thick ground from the frame to the trans to engine bolt to get the best engine ground. clean paint to bare metal, attach grounds with conductive grease, then paint over everything.

not much reason for the body sheetmetal to be grounded. with all the contact points it has its bound to find one somewhere.
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What would be a brand of conductive grease??
 
This rust bucket I have is really a problem so I did the next best thing and ran a separate ground wire to all the lights and they are bright.
 
1930 coupe said:
DO NOT use conductive grease with metal particles in lamp sockets or switches, it will short out your lights. If you want to use grease in your lamp sockets use contact grease, it does not conduct, its purpose is to keep water out and prevent corrosion. conductive grease is not needed on bolts and metal contact area, if the metal is clean and rust free it will conduct just fine without conductive grease, if you are concerned about rust any grease will prevent rust.
Bad grounds are usually from 80 years of thick rust between parts and on bolts. When cars are restored the rust is removed from the parts and bolts and then painted, when the parts are put back together the rust is gone and the bolts cut through the paint and make a good ground. You should not have to sand parts that have been properly restored. The only place that might need sanding would be where the ground strap connects to the frame.
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Yes very good point is to not use conductive grease where it can run (switches, lamps, contacts etc) Its best to think of it as liquid bare wires...

Which what mr 1930coupe said is true about having clean steel will conduct just fine, i mean henry did it and they lasted decades. Yea thick flakey rust is where your grounds have issues, like he said a light smear of any grease on the parts will prevent rust.

Personally tho i don't like relying on split washers and bolts to make the ground for me as i tighten them. While yes they do cut thru the paint i like knowing the parts are grounded as best they can by having clean steel on steel. Especially the main vehicle grounds.

Ive even wire wheeled the ground points on my modern vehicles and it made the truck run smoother with brighter headlights. All GM did was rely on star washers and self tapping screws to make good grounds (still paint under the terminals and rust under the star washers...)
 
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