Alternator Pivot Bolt

[bandita]

A friend is helping me change out my alternator on my '72 C10 Cheyenne. The pivot point has a "pin" (not sure of official name) that was really snug into the alternator. We had a heck of a time pulling that pin out far enough to pull out the alternator. And now, we can't get the pin back snug into the new alternator. I'm afraid to hammer too hard and warp the pin. The pin has an open slit that runs across so my friend tried vice grips too to shorten the diameter but as soon as the grips are removed, it goes back to original size (and the grips are too big to leave it on the same time as inserting the pin into the alternator).

My friend says that it's not important to have the pin fit snug into the alternator because the bolt is long enough to hold it in place, along with all the other attachments that's helping it keep the whole unit in place. My other concern is that the pivot bolt no longer tightens snugly like it did before. I'm afraid that vibrations over time can cause the bolt to inch it's way out. I'm thinking that if it wasn't that important, why wasn't the easy way like that done before (not inserting the pin into the alternator)?

So, is it important, and if so, how do we get the pin back into the alternator? Any special tool needed?

[Stocker]

I remember struggling with that roll pin (aka spring pin) when I replaced my alternator. Yes, I think it's necessary to keep it. If you get it lined up just right it should surprise you how easily it goes in. I may have compressed it a bit with a small vise grip, but I'm not sure about that. Shouldn't take much more than a light rap with a hammer, and you won't bend it -- they are pretty tough. If you do manage to tweak it, hardware stores sell them. Maybe a small shot of penetrating fluid will help get it started.

I know I fought it and fought it, and when it finally went in I thought geez, that wasn't so hard after all! Keep after it, you'll get it.

[bandita]

Great, thank you! That's very reassuring. I had an idea today too that I think might help...get the bolt in just enough to line it up, and then lightly tap the pin with a hammer like you mention. I didn't try it yet because I took the old alternator to get tested (even though it was tested while truck was running, I wanted to run one more test just to rule out anything else that might have been bad). That was when I found out that even though my alternator was bad, it's performance. So that's what I want to replace it with, and now I'm hoping the shop will take back the cheaper remanufactured one I bought, which I hope to find out tomorrow.

So now that I'm shopping on my own online (rather then having auto store pick one out), I'm confused with the different choices. All I want to do is match my old one (no brand name printed on it). Is there a way I can tell how many amps it originally had? I'm finding a range of 60-150 online. And what's this "1 wire" description? Some sites are hard to shop at because there's no picture of the backside, but this one I was able to find looks identical to the one I have: https://www.jegs.com/i/Proform/778/6...791+4294829790. But I'm confused why it would say 1 wire. I have 3 wires, and in this pic, it kind of appears to have the connections for 3 wires (looks like a black cover covering terminals 1 & 2, which I'm guessing is just a protective cover for shipping).

I'm also leaning toward this one: https://www.jegs.com/i/Powermaster/7...791+4294829790, since it doesn't mention anything about 1 wire, but there's no pic of the back to confirm. If I can't find out how many amps my old alternator was, could I mess anything up by getting one with mismatched amps?

[dmjlambert]

Here is a thread with some good info about alternators.
http://67-72chevytrucks.com/vboard/s....php?p=8253839
A 1 wire alternator is one that has been modified to allow use by connecting just the main 12V wire to it, and it figures out internally how much to charge the battery and how much current it needs to supply. Some folks on the forum like those, and some feel that best performance comes from the standard 3-wire setup, with 2 wires used to sense the voltages in the truck and to activate the alternator, and 1 bigger wire to send the main voltage.

3 wire alternators are the standard ones. Your truck probably came with a 10DN alternator that supplied 37 amps and it has an external regulator on your radiator support. Later models had internal regulators and don't need the regulator on the radiator support, and they also supplied more current. The case and fan of the alternator only allow a certain amount of cooling to happen in order to supply a lot of current. Although you may see ratings of aftermarket alternators that have high current, I don't know if they could really sustain high current with the same amount of air intake and fan design that the original had.

There is no such thing as mismatched amps. The various accessories you have draw whatever amount of current they need, and you just need to ensure your alternator and wiring can supply that amount of current. The truck was made with very few accessories that needed electricity, probably the biggest draw of current was the headlights and heater or A/C blower motor, and the original alternator was big enough for that stuff. If you have additional high-current accessories, you can add new 10 or 12 gauge wires directly to the alternator output terminal to run those, if you have a higher current alternator. Ground and 12V terminal wires both need to be adequate size to run the devices you have in mind.

Your choices of later model alternators include 10SI, 12SI, CS130, and CS144. With each new series came higher current and supposedly better performance. All of them require a little bit of wiring modification or adapter to use a new style plug at the alternator. CS130 and CS144 requires a resistor to be added to the wiring. CS144 is about 1 inch larger in size.

I'm not a big fan of the Chinese made alternators, as I've already done that and replaced when mine was worn out after 1 year and about 5000 miles. For my next one I went up to O'Reilly and got one that has made in USA and Remy stamped into the case. https://www.oreillyauto.com/detail/b...R111878A&pos=0

[bandita]

Thank you for the detailed info!

I hope to avoid the hassle of any rewiring. Is there a way to determine if my current wires are 10 or 12 gauge? I currently have an 80 amp alternator on order from O'Reilleys (https://www.oreillyauto.com/detail/b...d?q=5122&pos=1. I know it says it's not compatible for a '72, but on O'Reilley's system at the store, it says it is, and the pictures are identical to my old one). I hope that will be sufficient for what I have. The previous owner did a lot of modifications, including a high performance sound system. The one I ordered also doesn't state whether it's 10SI, 12SI, or CS130, and CS144. Based on one of the diagrams on the thread you sent me, I think I can rule out CS130. My current set up looks very similar to the 12SI diagram (with the only difference being that I don't have a brown wire. Mine is yellow, unless it got that way from age). I don't know when this truck was rebuilt but I know it was before 2002, when my dad bought the truck and that it was built to be a racer. Can that be a clue to the possibilities of which SI or CS and what amps it might be? I showed the O'Reileys rep my old alternator, and he helped me pick this one out, but I failed to mention to him my suped-up sound system. I'm tempted to get a 100 or 120 amp, to be on the safe side, but not sure how to find out if my current wires can handle that. It's very possible that the previous owner already already upgraded it.

[dmjlambert]

If your truck has had modifications by previous owners, you could have just about anything. And the wire colors may not match what the factory did. Here is a good article I bookmarked that should help you identify your alternator if you have a 10SI or 12SI and that would be a start.
http://www.madelectrical.com/electri...elcoremy.shtml

[bandita]

Very informative article. Thank you, and Merry Christmas!