Stuck Alternator Post Nut

Gotta love that wiring . . .
Post Reply
AlexD
Posts: 51
Joined: Mon Sep 07, 2020 10:38 am
Your car is a: 1980 Spider 2000

Stuck Alternator Post Nut

Post by AlexD »

Encountered a strange situation yesterday while attempting to install headlight relays. Laid everything out and before I started cutting the existing connections to connect with the relay wiring I thought I'd disconnect the nut on the alternator post so I can start with the power feed. Glad I did that as it appears that the nut is fused/stuck to the connector on the end of the green wire coming from the starter. When I turn the nut, the wire twists with it even after applying some penetrating oil. I'm afraid that I'm going to compromise the wire connecter if I take any further action but am not sure there are any other options beyond cutting the connector and wrenching the nut off.

Has anyone ever encountered this and any suggestions? Seems simple enough that there are maybe 1 or two choices to try before having to replace the wire connector.
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Stuck Alternator Post Nut

Post by 18Fiatsandcounting »

I'm sure you've likely done this, but disconnect the battery first.

Yes, what you describe is fairly common. The output post on the alternator (the B+ post) has 2 nuts on it, one on each side of the green wire connector. If the nut on the bottom of the connector is not tight enough, the post will turn as you try to loosen the top nut. My approach would be to disconnect the alternator from the engine so you can work on it easier (perhaps on the fender protected with a towel), and then you can use a very thin 10mm wrench to hold the lower nut as you loosen the top nut. Very thin needle nose pliers might also work. Or tighten the lower nut some more and see if you can then loosen the outer nut.

-Bryan
spider2081
Patron 2024
Patron 2024
Posts: 3015
Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
Location: Wallingford,CT

Re: Stuck Alternator Post Nut

Post by spider2081 »

There should be a flat washer between the ring terminal and the nut. This prevents the nut from gouging into the ring terminal. I would try holding the ring terminal with a pair of pliers and then turning the nut.
AlexD
Posts: 51
Joined: Mon Sep 07, 2020 10:38 am
Your car is a: 1980 Spider 2000

Re: Stuck Alternator Post Nut

Post by AlexD »

18Fiatsandcounting wrote:I'm sure you've likely done this, but disconnect the battery first.

Yes, what you describe is fairly common. The output post on the alternator (the B+ post) has 2 nuts on it, one on each side of the green wire connector. If the nut on the bottom of the connector is not tight enough, the post will turn as you try to loosen the top nut. My approach would be to disconnect the alternator from the engine so you can work on it easier (perhaps on the fender protected with a towel), and then you can use a very thin 10mm wrench to hold the lower nut as you loosen the top nut. Very thin needle nose pliers might also work. Or tighten the lower nut some more and see if you can then loosen the outer nut.

-Bryan
Yes absolutely disconnected the battery before going anywhere near the alternator (or doing any other electric work for that matter) - appreciate the call-out, though.

It hadn't dawned on me (nor did I notice yesterday) that it might actually be the entire post turning and not just the nut and ring terminal. That makes sense and I'm glad that I didn't crank the nut/post more than about 1/4". I couldn't get a 10mm on the inside/lower nut so I'll try needle-nose pliers before I go out and find a thinner wrench. I might also be able to get a pair of vice grips on the exposed end of the post as a last resort to at least loosen the nut enough to make space for the 10mm.
AlexD
Posts: 51
Joined: Mon Sep 07, 2020 10:38 am
Your car is a: 1980 Spider 2000

Re: Stuck Alternator Post Nut

Post by AlexD »

spider2081 wrote:There should be a flat washer between the ring terminal and the nut. This prevents the nut from gouging into the ring terminal. I would try holding the ring terminal with a pair of pliers and then turning the nut.
I expected to see a washer between the ring terminal and nut but couldn't see one (and it's not acting like there is one). I did try holding the ring terminal while turning the nut but that didn't work - apparently it's the whole post that's spinning (likely due to a loose lower/inner nut. I'm going to try isolating the lower nut or, as a last resort, the exposed end of the post, to see if I can get the outer nut loose enough to tighten down the post.
spider2081
Patron 2024
Patron 2024
Posts: 3015
Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
Location: Wallingford,CT

Re: Stuck Alternator Post Nut

Post by spider2081 »

If I'm remembering correctly he head of the output bolt fits into am insulated well that prevents the bolt from turning. The lower nut would have to be very backed off for the head to be out of the retainer. If the entire B+ bolt is spinning I would want to look inside the alternator.
AlexD
Posts: 51
Joined: Mon Sep 07, 2020 10:38 am
Your car is a: 1980 Spider 2000

Re: Stuck Alternator Post Nut

Post by AlexD »

So it dawned on me out of nowhere to look in my newly acquired Fiat toolkit and there sat a thin 10mm wrench in all its golden glory. Didn’t care that it was dark out - grabbed a flashlight, popped the hood, and got a bite on the lower nut allowing me to remove the upper nut with ease. There actually was a very small washer between the ring terminal and the upper nut which was good to see. I snugged down the lower nut so this doesn’t happen again and am all set to hook up power to the relays tomorrow.

I had no intention of ever actually using that toolkit when I bought it - wanted it (and the jack) to make the car more “complete”. Damn thing just paid for itself.

Thanks for the replied and input - much appreciated!!
Post Reply