I did something stupid. I just got this reman alt in the mail. It didn't come with the pulley, so I was in the process of swapping out the pulley from my bad alt. On the bad alt, I couldn't get the nut holding the pulley to turn without turning the shaft, so I took the alt case apart, which allowed my to put the part of the alt that was attached to the shaft on the inside, in a vise clamp, and then I could turn the nut holding the pulley on to remove it. When I was putting the pulley on my new alt, once the nut was screwed down, when I was trying to tighten it, it was spinning the shaft. So I thought I'd crack open the case like I had done with my bad alt, put it in the vise, and tighten it up. Bad idea. On the inside of the alt, when I pulled the case apart, it ripped this magnet out of wherever it was supposed to be attached with this copper wire. Pictures below. Does anyone know how this magnet is supposed to be attached and situated? Is this something I should even bother with considering my lack of mechanical expertise?

You can see in the picture below, there is another magnet attached to a copper wire that runs to that bolt on the right. I don't see a similar place to attach a wire on the left side bolt. I have no idea where that wire went.

 

That dark gray block is not a magnet. It is one of the brushes. I'm pretty sure there should be two. They fit inside the red plastic piece, and are spring-loaded to ride against the slip rings on the armature.

Only one brush is grounded, the one with the broken wire. Do you see a second brush anywhere? Does that red block have provisions for two brushes?

To reassemble, you will obviously have to fix that broken wire. You may be able to get a replacement brush holder assembly, which will include new brushes. There is usually some provision to hold the brushes retracted during assembly, such as a small hole for a pin in front of the brushes. Once assembled, you remove the pin and the brushes will extend.

 

Here's one possible source for a replacement brush holder assembly.

Edit, corrected link for a better match and added picture:

https://store.alternatorparts.com/39...ternators.aspx





I'm NOT saying that is exactly what you need, but it looks like the same basic type as in your pictures. From your other thread, I see you've installed a Motorcraft GL212RM, so I searched for brushes for that model.

 

The second brush is there. In the pictures, you can see one of the screwheads has a copper wire coming off it, and runs under that red plastic piece. The other brush had fallen under the red plastic piece, and is attached to that wire.

I took apart my old alt to see where the broken brush/wire should attach. I removed both of the screws from the plastic piece, and on my old alt, the other brush wire is attached to a flat metal bit affixed to the alt housing, underneath the plastic piece. I think one of the wires on the back of the alternator connects here and runs to the voltage regulator.

Unfortunately the red plastic piece on my new alt does not come loose after removing those screws. I tried prying it loose gently with a screwdriver, and the plastic started breaking apart.

I went ahead and purchased yet another alternator. I might try and get this other one fixed as I have time, but it seems like fairly delicate work. Lesson learned I guess.

 

What you are messing with is the "field" of the alternator. To generate power, all you need to do is pass copper wires by a magnet. In your alternator, the copper wires are stationary on the outside (the stator) and the magnet is spinning (the rotor you clamped in the vise). Those brushes that broke transfer power to the spinning center rotor, and turn it into a magnet. So when it spins by the coils on the outside, it generates power through those coils.

You are correct, power for the rotor comes from the regulator. The regulator varies the voltage to this wire (the field wire) and that varies the strength of it's magnetism. If it's a strong magnet, it generates more power. Weaker, less power. That's how the regulator controls the output of the alternator.

Not a complete loss, you learned a lot taking it apart. Do you have a electric/battery/air impact gun? That is the way to take off and install these pulley nuts. Might be time to invest in one, or simply go to a friendly local shop and let them take 5 seconds to put it on for you.

 

Next time you need to remove the nut you can try 2 things.
Using a box wrench or socket & breaker bar that fits the nut use a hammer to hit the wrench or bar to "shock" the nut loose.
Might be easier to do this on the motor and belt in place to help hold the ALT and keep the pulley from turning.
You just need to loosen the nut then remove from motor to do the swap.
Can do the same putting it back together.

OR

Take the old & new ALT to a local garage and have them use an impac gun to loosen and tighten the nut. throw them a $5 or $10 for their time of less than 5 mins.
Well worth the money. BTW I have a compressor & gun and how I do it.
Dave ----

 

This video has more details about replacing the brushes and brush holder. It seems like you may have missed one of the fasteners on the outside of the rear case:



Also please see I corrected the link in my previous post above, and added a picture. From my limited understanding of the different alternator types, the brush holder in your pics is used on the small case 1G alternator. This vendor has lots of details and pictures:

https://store.alternatorparts.com/fo...tor-parts.aspx