Battery hold down bolts corrosion

[Hot pepper red]

Hi, I noticed that I have corrosion on the bolts that hold the battery tray to the body, and I am curious if anyone else has this issue? The paint on the bolts is peeling off, and I don't see any visible signs of the battery leaking electrolyte. I know batteries are vented, and I sprayed battery terminal anti corrosion spray on the bolts. This is frustrating that Ford didn't design the bolts to be corrosion resistant.

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[kshaw]

I would bet that these are cheap fasteners that do not have much corrosion resistance. I doubt that the issue is acid related and more likely dissimilar metal corrosion. If I wanted to keep existing hardware, I would apply ACF-50, Corrosion-X, or Boeshield T-9 after wire brushing any rust or corrosion. A more permanent fix would be to take the fasteners to the hardware store and replace with stainless steel.

 

[Hot pepper red]

I forgot to add that the top of the fastener paint is peeling off from battery corrosion and the battery tray is plastic.

 

[Dude]

So if it’s not battery acid corroding the battery hold down bolts and the hold down bolts are in contact with the plastic battery tray so it’s not dissimilar metal corrosion and battery terminal anti corrosion was sprayed on the bolts then what is causing the bolts to corrode

 

[kshaw]

I forgot to add that the top of the fastener paint is peeling off from battery corrosion and the battery tray is plastic.

So you are saying that the fastener's only screw into plastic and not any kind of metal underneath or on edges of the plastic? That would have to be very strong plastic since batteries are often 35-60 lbs or so.

 

[elav]

The battery tray is plastic but I believe the fasteners are screwed into a metal support (aluminum?). It would be helpful if you posted pictures as you remove nuts to free the battery - so I'm not sure which fasteners you are referring to.

 

[Hot pepper red]

Battery holder down pictures.

 

[Dude]

Any chance that corrosion was caused by salt spray from Winter driving ?

 

[Hot pepper red]

No, I live in Colorado and they use magnesium chloride on the roads... I have seen this before on other vehicles I have owned--the paint on the hardware wasn't corrosion resistant. I am a former aircraft mechanic and we would use bituminous paint to prevent corrosion in the battery box area on airplanes. I know how to fix the problem, and I am going to take it to my Ford dealer to replace it under warranty. I'm curious if anyone else has seen this.

 

[Dude]

No, I live in Colorado and they use magnesium chloride on the roads... I have seen this before on other vehicles I have owned--the paint on the hardware wasn't corrosion resistant. I am a former aircraft mechanic and we would use bituminous paint to prevent corrosion in the battery box area on airplanes. I know how to fix the problem, and I am going to take it to my Ford dealer to replace it under warranty. I'm curious if anyone else has seen this.

Hmmm … “.. as CDOT states, any exposed metal will corrode when magnesium chloride and water are present”

No type of salts are used in roads where I live
I have not seen any corrosion under the hood

 

[Hot pepper red]

There aren't any other fasteners that are corroding near the battery...

 

[Major Kong]

my guess
zinc plated somewhere in the mix
unintentional sacrificial anode

"This type of accelerated corrosion between dissimilar metals is referred to as galvanic corrosion. Because galvanic corrosion can occur at a high rate under certain circumstances, it is important to evaluate the combination of galvanized steel with other metals to determine if galvanic corrosion is of concern. "
https://galvanizeit.org/design-and-fabrication/design-considerations/dissimilar-metals-in-contact

 

[Hot pepper red]

my guess
zinc plated somewhere in the mix
unintentional sacrificial anode

"This type of accelerated corrosion between dissimilar metals is referred to as galvanic corrosion. Because galvanic corrosion can occur at a high rate under certain circumstances, it is important to evaluate the combination of galvanized steel with other metals to determine if galvanic corrosion is of concern. "
https://galvanizeit.org/design-and-fabrication/design-considerations/dissimilar-metals-in-contact
Have you experienced this battery hold down fasteners corrosion on your vehicle?

 

[Hot pepper red]

I found this on the Internet that is enlightening about corrosion from the acid in batteries: "The color of the corrosive buildup can tell you a lot about what is causing your battery to corrode. White or gray corrosion is caused by a battery that's leaking excessive battery acid due to a crack in the battery's casing. A buildup of green material is caused by oxidation within the battery's copper cable. Blue corrosion is copper sulfate which results when the copper terminal clamps are exposed to hot sulfuric acid." The color on the hardware is a whitish grey and I don't see any signs of a cracked case--more than likely it's normal battery venting with hardware not designed to withstand corrosion.

 

[Major Kong]

"Have you experienced this battery hold down fasteners corrosion on your vehicle? "
not so much on the BS as other vehicles
the rusting situation you presented had the appearance of dissimilar metal corrosion
think of the hot water tank scenario
di-electric piping needed between copper pipe and steel tank

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