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Discussion Starter · #1 ·
Yep, it's been a long time since this old gal has needed your help.

I have a 93 GMC K2500 6.5TD with dual batteries. A couple years ago, I replaced the passenger side positive post with this stainless steel style
642213

The original terminal that had a plastic cover had cracked and fell apart ...it had gotten the blue corrosion.
Twice this connection has gotten the blue stuff again. I take both terminals off (it also has the cable that goes to the other battery) and clean with baking soda/water very well. Then wire brush and steel wool everything super clean. But, it still corrodes after a few months. The other day I was all set to go and the truck was dead. No prior indication of a problem. Did a quickie clean with bs/water and I charged the battery...it didn't take long and truck was perfect all day.
So, I'm thinking maybe I'm not installing this correctly? How do you "stack" the 2 cable ends? I put them next to each other on the threaded end that goes into the battery with a s/s flat washer and then a s/s lock washer because the bolt is a tad too long. The corrosion seems to start between the copper cable ends.

I'm taking it all apart in the morning and am hoping to get some guidance from y'all :)

Forgot to mention that I put dielectric grease on after connecting. Maybe not enough? And, yes, I disconnect the negatives first.
 

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Have you peeled off the plastic cover?
If not, just cut it out and leave the metal part only.
It should be good and easy to clean, if necessary.
That plastic cover is not really necessary.

I used the same type of terminal but made of brass.
 

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Just so you know. Dielectric grease is an insulator. It does not conduct electricity. You should not use it where metal to metal contact is required. It is ok to use it to cover a battery terminal after assembly to keep out moisture, corrosion,ect. But using it on the threads and metal parts that make the connection can cause problems charging and starting.
Also if you are getting a lot of corrosion. The batteries may be leaking at the terminals. Side post batteries are known for that problem. That is why many switch out to top post.
 

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It is your battery leaking acid fumes around the lead to plastic bond.
The ONLY battery manufacturer that seals that correctly is DEKA(East Penn). They also make most Napa and Caterpillar batteries.

Now that my 200+ batteries in service are DEKA's, I don't have to carry my battery cable ends and tools anymore. It also helps that they typically last 5-10 years, even on my seasonal equipment.

This what was in there originally
Screenshot_20210429-113137_Chrome.jpg
 

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Discussion Starter · #5 ·
Have you peeled off the plastic cover?
If not, just cut it out and leave the metal part only.
It should be good and easy to clean, if necessary.
That plastic cover is not really necessary.

I used the same type of terminal but made of brass.
Yes, the plastic is off both ends. I can clean the copper to a nice shine.
 

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Discussion Starter · #6 ·
Just so you know. Dielectric grease is an insulator. It does not conduct electricity. You should not use it where metal to metal contact is required. It is ok to use it to cover a battery terminal after assembly to keep out moisture, corrosion,ect. But using it on the threads and metal parts that make the connection can cause problems charging and starting.
Also if you are getting a lot of corrosion. The batteries may be leaking at the terminals. Side post batteries are known for that problem. That is why many switch out to top post.
Thanks for the info Tommy.
I apply the dielectric grease AFTER everything is assembled. It's the last thing I do. It still corrodes at the copper cable ends. That's why I'm thinking maybe not enough? If I use a lot, is it difficult to charge the battery if needed? How to get the grease off?

What if I put one cable on the threaded (right side in pic) side and the other on the bolt side (left side in pic) to separate them. Would it work?
 

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Actually, East Penn made batteries now is at WM. The barcode on top showing serial no. start with "EP".
I am not sure if the quality is the same as Deka but I have a couple of them in the suburban now and all my Toyotas now.
They are good price.
 

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Stainless + copper or stainless + aluminum will always corrode the non stainless part. Dissimilar metals.
 
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Hey McCall nailed it. The blue stuff is copper sulfate. The sulfuric acid in the battery is fuming and slowly reacting with the copper terminals. Just a matter of time before you’ll need to replace them. I see this happen quite often on trailer breakaway systems with those awful little Chinese 12v 4Ah or 7Ah batteries.
 

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Discussion Starter · #10 ·
UPDATE:

I ended up replacing the batteries yesterday. They wouldn't hold a decent charge overnight.

When the guy read the sticker, THEY WERE FROM 1/11.....!!!!!!!!!!!!! Over 10 years old lol. The owner of the shop couldn't believe it. So I bought another pair of the same brand. Everlast...name sure fits!

OT--- Happy 32nd Birthday to my best friend/partner of 27 years....my mare Ruby 🐴

Thanks everyone!
 

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UPDATE:

I ended up replacing the batteries yesterday. They wouldn't hold a decent charge overnight.

When the guy read the sticker, THEY WERE FROM 1/11.....!!!!!!!!!!!!! Over 10 years old lol. The owner of the shop couldn't believe it. So I bought another pair of the same brand. Everlast...name sure fits!

OT--- Happy 32nd Birthday to my best friend/partner of 27 years....my mare Ruby 🐴

Thanks everyone!
I think you find the culprit for your issue, not as expected I am sure.
I learned a long time ago after I got the suburban 15 years ago, I need to LOAD (not voltage) test the batteries, one at a time (in the case of this truck since it has 2) before doing anything else with any issues to the truck or any vehicle I may have trouble with.
 
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