Alternator voltage / electrical problems? Check your distribution block.
Thread Starter
CF "Young" Senior Member
Joined: Feb 2005
Posts: 4,034
Likes: 26
From: Cupertino CA
St. Jude Donor '12
Alternator voltage / electrical problems? Check your distribution block.
Just figured I'd share my recent experience with our '86, in case this useful bit of info can help anyone else out.
We've had a number of issues in recent months with altenators, usually resulting in them not outputting enough voltage and eventually having to be replaced.
On the most recent one, as soon as I replaced the altenator, I was getting 11v at start-up and it steadily declined to 6 or 7. I pulled out the alternator and battery, took them to Kragen's and had them tested, and both came back ok. Upon returning home, I noticed that the distribution block (which is located just behind the battery) was looking worse for wear, and attempted to disassemble it to clean the contacts. The nut and bolt just spun, and since my cordless Dremel was charging, I put some dieletric grease on it and called it 'ok'.
When I started the car up again, it was getting 13.5v and was running ok, but stumbling a little, so I got out to make sure a spark plug cable wasn't loose or something. As I was walking back to the driver's side, the car just shut off. Completely. As in, absolutely nothing was getting any power, at all. I went around checking all the cables, making sure the battery was grounded good, etc etc. Nothing.
So this morning I went over to our trusty mechanic and talked it over with him. As soon as I mentioned the distribution block, he stopped me and walked over to a late 80's / early 90's Caddilac on his lot that was missing it's top half (literally.. anything above the fender line was gone, roof included). He pulled off the distribution block from that car's firewall, which was identical to the one from the '86, and gave it to me.
Fast forward to this evening, and when I again attempted to disassemble the '86's old distro block, the plastic just disintegrated around the bolt. After some coercion, the rusted-on nut came off. Now charged, I used the cordless Dremel to clean the gunk and corrosion off the wire ends, coated them in dieletric grease, and reassembled it onto the 'new' block. I put the battery back in, fired up the car, and immediately was getting 14v steady.
Cliff notes:
If you're having low voltage issues from your altenator, check to make your the distribution block behind your battery is in good clean condition.
Hope someone finds this handy.
We've had a number of issues in recent months with altenators, usually resulting in them not outputting enough voltage and eventually having to be replaced.
On the most recent one, as soon as I replaced the altenator, I was getting 11v at start-up and it steadily declined to 6 or 7. I pulled out the alternator and battery, took them to Kragen's and had them tested, and both came back ok. Upon returning home, I noticed that the distribution block (which is located just behind the battery) was looking worse for wear, and attempted to disassemble it to clean the contacts. The nut and bolt just spun, and since my cordless Dremel was charging, I put some dieletric grease on it and called it 'ok'.
When I started the car up again, it was getting 13.5v and was running ok, but stumbling a little, so I got out to make sure a spark plug cable wasn't loose or something. As I was walking back to the driver's side, the car just shut off. Completely. As in, absolutely nothing was getting any power, at all. I went around checking all the cables, making sure the battery was grounded good, etc etc. Nothing.
So this morning I went over to our trusty mechanic and talked it over with him. As soon as I mentioned the distribution block, he stopped me and walked over to a late 80's / early 90's Caddilac on his lot that was missing it's top half (literally.. anything above the fender line was gone, roof included). He pulled off the distribution block from that car's firewall, which was identical to the one from the '86, and gave it to me.
Fast forward to this evening, and when I again attempted to disassemble the '86's old distro block, the plastic just disintegrated around the bolt. After some coercion, the rusted-on nut came off. Now charged, I used the cordless Dremel to clean the gunk and corrosion off the wire ends, coated them in dieletric grease, and reassembled it onto the 'new' block. I put the battery back in, fired up the car, and immediately was getting 14v steady.
Cliff notes:
If you're having low voltage issues from your altenator, check to make your the distribution block behind your battery is in good clean condition.
Hope someone finds this handy.
Le Mans Master
Joined: Jul 2009
Posts: 8,041
Likes: 2
From: EOF ★ Kaliforniastan ★
St. Jude Donor '10
Just figured I'd share my recent experience with our '86, in case this useful bit of info can help anyone else out.
We've had a number of issues in recent months with altenators, usually resulting in them not outputting enough voltage and eventually having to be replaced.
On the most recent one, as soon as I replaced the altenator, I was getting 11v at start-up and it steadily declined to 6 or 7. I pulled out the alternator and battery, took them to Kragen's and had them tested, and both came back ok. Upon returning home, I noticed that the distribution block (which is located just behind the battery) was looking worse for wear, and attempted to disassemble it to clean the contacts. The nut and bolt just spun, and since my cordless Dremel was charging, I put some dieletric grease on it and called it 'ok'.
When I started the car up again, it was getting 13.5v and was running ok, but stumbling a little, so I got out to make sure a spark plug cable wasn't loose or something. As I was walking back to the driver's side, the car just shut off. Completely. As in, absolutely nothing was getting any power, at all. I went around checking all the cables, making sure the battery was grounded good, etc etc. Nothing.
So this morning I went over to our trusty mechanic and talked it over with him. As soon as I mentioned the distribution block, he stopped me and walked over to a late 80's / early 90's Caddilac on his lot that was missing it's top half (literally.. anything above the fender line was gone, roof included). He pulled off the distribution block from that car's firewall, which was identical to the one from the '86, and gave it to me.
Fast forward to this evening, and when I again attempted to disassemble the '86's old distro block, the plastic just disintegrated around the bolt. After some coercion, the rusted-on nut came off. Now charged, I used the cordless Dremel to clean the gunk and corrosion off the wire ends, coated them in dieletric grease, and reassembled it onto the 'new' block. I put the battery back in, fired up the car, and immediately was getting 14v steady.
Cliff notes:
If you're having low voltage issues from your altenator, check to make your the distribution block behind your battery is in good clean condition.
Hope someone finds this handy.
We've had a number of issues in recent months with altenators, usually resulting in them not outputting enough voltage and eventually having to be replaced.
On the most recent one, as soon as I replaced the altenator, I was getting 11v at start-up and it steadily declined to 6 or 7. I pulled out the alternator and battery, took them to Kragen's and had them tested, and both came back ok. Upon returning home, I noticed that the distribution block (which is located just behind the battery) was looking worse for wear, and attempted to disassemble it to clean the contacts. The nut and bolt just spun, and since my cordless Dremel was charging, I put some dieletric grease on it and called it 'ok'.
When I started the car up again, it was getting 13.5v and was running ok, but stumbling a little, so I got out to make sure a spark plug cable wasn't loose or something. As I was walking back to the driver's side, the car just shut off. Completely. As in, absolutely nothing was getting any power, at all. I went around checking all the cables, making sure the battery was grounded good, etc etc. Nothing.
So this morning I went over to our trusty mechanic and talked it over with him. As soon as I mentioned the distribution block, he stopped me and walked over to a late 80's / early 90's Caddilac on his lot that was missing it's top half (literally.. anything above the fender line was gone, roof included). He pulled off the distribution block from that car's firewall, which was identical to the one from the '86, and gave it to me.
Fast forward to this evening, and when I again attempted to disassemble the '86's old distro block, the plastic just disintegrated around the bolt. After some coercion, the rusted-on nut came off. Now charged, I used the cordless Dremel to clean the gunk and corrosion off the wire ends, coated them in dieletric grease, and reassembled it onto the 'new' block. I put the battery back in, fired up the car, and immediately was getting 14v steady.
Cliff notes:
If you're having low voltage issues from your altenator, check to make your the distribution block behind your battery is in good clean condition.
Hope someone finds this handy.
Melting Slicks
Joined: Apr 2011
Posts: 3,496
Likes: 475
From: New Jersey
Sorry to resurrect such an old thread but I experienced precisely the same symptoms, and decided, after replacing the alternator to no avail (duh) to pull the battery and inspect all the wiring. The distribution block was in the same shape as the OP described, with clear evidence of prior arcing/melting points. I removed it, cleaned everything, replaced a connector on one wire, and drilled out the mounting stud, placing a screw through the block and mounting everything to that. Of corse, the screw cannot be allowed to ground so I have a wood shim behind it currently. I intend to replace the block ASAP. Clearly this was a fire waiting to happen.
