rear battery terminal melted

[Hammy]

newish here first post.

i have a 1986 m1008 cucv and all the electrical is standard to my knowledge.

i replaced the batteries and had the alts. rebuilt but heres where the problem started.

the batteries would not stay charged and died in about 3-4 days. so we started leaving the batteries disconnected. my dad connected the batteries to use the truck and the rear positive cable had a huge arc and welded itself to the post. so we thought it would be the glow plug relay since it wasnt cycling correctly. replaced the GPR and it seemed like that fixed our drain.

today i drove the truck about 160 miles and on the drive the gen lights were barely on and turned off as the rpms went up. not sure why since the alts were rebuilt.

when i got home i popped the hood to double check the connections on the alts. and the pos. post on the rear battery was completely melted.

any ideas what is goin on here? i am learning this truck on the fly and getting a crash course i guess.

thanks for any help, also i've searched for days to try to solve this but couldn't find anything that sounded similar.

 

[Hammy]

I should note the resistor behind the air filter was too hot to touch after the welding incident which is what led us to the GPR...

 

[Barrman]

When you write that you had the alternators rebuilt. Did you let the rebuilder know they were isolated ground alternators? That big spark was probably an alternator killing itself. The resistor on the firewall is for stepping down the stock glow plug power from 24 volts to 12 volts. It will only get hot if it is plugged in and the glow plugs are working. It is not related to the alternators or battery hook ups unless the glow plug system is turned on. I know this is kind of a cheap answer, but I would suggest you start over again with the trouble shooting section of the -20 manual. Start with the alternator section and then go to the glow plug section. You might need a new batter or two as well.

 

[MWMULES]

The only times I have seen a battery posts melt (I did it once) was when the terminal was not tight to the post and the resistance did it. Happen during starting a Duce and did not realize till I got back home. Or by going directly to ground.

 

[randini]

Anyone ever try to repair a melted terminal?

 

[phil2968]

My old battery shop had a mold that he used to repair one for me once. He melted lead to form a new post. http://batteriesbyfisher.com

 

[coxoncall]

I know this is a bit old,

We just had a M35 battery drain. We pulled both batteries off to charge separately. Went to install them and melted 2 posts. Long story and cleaning later, turns out it was the starter cable. We loosened it and then we lost continuity. on the main battery cables. brushed the connectors off and tightened. Connected the battery cables in the following order:
Battery Jumper Positive
Battery Jumper Negative
Truck Positive
Truck Negative

No sparks or arc welding/melting.

She started right up and no problems since. I spent 4 hours today and 6 hours over this week trying to figure out the problems. I hope this helps someone in the future save some time and money.

 

[Flyingvan911]

I have made a temporary repair before by fluxing the heck out of the melted spot and filling it with solder. Mine melted a hole in the middle so it was dish shaped and easy to solder. At the time it arced it was so bad there was no way I could start the truck without doing more damage. My next fear was melting it off completely and having no lights. I was on a slight grade so I roll started it. The pic is in bad focus but here it is.