2002 Original Alternator

[PowrPly]

I bought my 4Runner brand new in August of 2002, Sport Edition. It now has 285,000 miles and still looks great. I do all of my own maintenance and I keep thinking about my alternator. It’s original and shows no signs of weakness. Do I wait for it to fail or do I make a preemptive strike and replace it?

 

[cblock406]

Mine just went out and for several months before the electrical system would cut out for a second and come right back on and the battery light would come on in the gauge cluster. I should have replaced it right away but was super busy and didn’t do it until it was too late and it died on me in traffic.

 

[mtbtim]

A common reason alternators stop charging effectively is due to worn down brushes. If I were you, I'd keep your OEM alternator and just check the brushes to see how they're doing. The brushes cost very little and it's not a hard job.

Here's a video [MENTION=102606]infamousRNR[/MENTION] and I did for this job.

<iframe width="560" height="315" src="https://www.youtube.com/embed/71_kBhg6_-A" frameborder="0" allowfullscreen></iframe>

 

[nglayton]

@%1;2mtbtim, Great video. One note, I think you should disconnect the positive battery cable, not the negative side. However I guess it's still disconnected either way, I just think the common practice is the positive cable. I could be wrong.

Where did you find the brush kit for the alternator? was it online? do you have the part number?

 

[mtbtim]

@%1;2mtbtim, Great video. One note, I think you should disconnect the positive battery cable, not the negative side. However I guess it's still disconnected either way, I just think the common practice is the positive cable. I could be wrong.

Where did you find the brush kit for the alternator? was it online? do you have the part number?

You're always suppose to remove the negative cable first. If you try to remove the positive first, you could accidentally become the ground pathway and that's not good. Here's an article from Popular Mechanics:
Battery and Negative Terminal - How to Disconnect a Battery

The part number for the brushes is in the video description. I just bought them from my local dealer.

 

[alanflies]

You're always suppose to remove the negative cable first. If you try to remove the positive first, you could accidentally become the ground pathway and that's not good. Here's an article from Popular Mechanics:
Battery and Negative Terminal - How to Disconnect a Battery

The part number for the brushes is in the video description. I just bought them from my local dealer.

That's a BIG 10-4...Always the negative terminal. Don't want to become part of the circuit. Don't want the energy finding a new circuit either.

 

[amalik]

That's a BIG 10-4...Always the negative terminal. Don't want to become part of the circuit. Don't want the energy finding a new circuit either.

To clarify, you want to disconnect the negative terminal first because the electrons in the battery flow from negative to positive, right? i.e you're cutting the 'flow' off from the source?

 

[ZionXIX]

The brushes are actually quite cost effective to replace. There is some labor involved but its not too bad. You dont want to end up replacing your OEM alternator for a parts store alternator. I noticed on Amayama.com they have listed the brushes for $9.60 and the regulator for $81.06. That is a steal, I may consider replacing both parts as a preventative maintenance on my next runner.

 

[19963.4lsr5]

If you get electrocuted with 12vdc your time was up anyway


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[Buckaroo]

To clarify, you want to disconnect the negative terminal first because the electrons in the battery flow from negative to positive, right? i.e you're cutting the 'flow' off from the source?

Depending on the theoretical approach you subscribe to, electrons can flow one way or the other.... [MENTION=102597]IBallEngineer[/MENTION] can discuss the details....interesting discussion over a beer but regardless, you are correct, standard automotive practice is to disconnect the negative first and re-attach it last.

Buckaroo

 

[nissanh]

Yes, do as MTBTIM said. The brushes are the only thing that can go bad if you have the factory electrical accessories. I am at 210 K miles and still the original alternator. Got an extra brush kit stored in the jack area to use in case. Planning to do the brush kit on my 230K mile LandCruiser soon because the removal of the alternator in a 2uzfe is not fun to do anywhere else than at home.

Camelback has the brush kit for $15ish. I checked the Amayama and they don't have the cheaper shipping option available at present (about a week ago)

 

[Buckaroo]

What about the diode set, guys? I am still running my original alternator at 245,000 miles but that is typically something I worry about with old alternators......

Buckaroo

 

[nissanh]

You can disconnect the battery from either terminal but you want to AVOID any short circuits. This is why you remove the negative terminal FIRST. The direction of flow of electrons is not an issue here.

Diodes are usually OK. I had to replace a diode set on a hilux because excessive current was drawn from the alternator. If you are replacing the diodes, stay with OEM, otherwise you will not get a 13.5 V or more of charging at idle with major accessories on.

 

[nglayton]

You're always suppose to remove the negative cable first. If you try to remove the positive first, you could accidentally become the ground pathway and that's not good. Here's an article from Popular Mechanics:
Battery and Negative Terminal - How to Disconnect a Battery

The part number for the brushes is in the video description. I just bought them from my local dealer.

Interesting..I'm not sure I would call that an "article", more like a Q and A response, but anyway..... I would say if your going to short the terminals together, then all bets are off it doesn't really matter what terminal you take off first.

Removing the negative first and there for removing the ground from the entire vehicle will make it less likely that you will short the terminals. I get that. Thanks for the explanation. Realistically I guess we should always be removing BOTH cables. I'm just to lazy for that and more careful than to short them while I'm doing it.

 

[djaye.]

To clarify, you want to disconnect the negative terminal first because the electrons in the battery flow from negative to positive, right? i.e you're cutting the 'flow' off from the source?

You disconnect the negative first (and re-connect last) because even if your wrench, ratchet, harborfreight visegrips, etc makes contact with the negative-ground body or chassis in the process, nothing bad is going to happen.

Do the positive first and accidentally make contact, and you'll be doing some unintentional welding.

 

[AntleredRuin]

Just make sure your metal hood prop doesn't fall across the battery terminals.
My dad saw this once with a customer's car...towed in because it 'wouldn't start'. I wonder why?

So back to topic, yes, I'd replace the brushes. However, you'd usually have some warning that the alternator is on its way out first. Weird squealing, then battery light coming on. If that happens, don't turn off the car until you're sure you are where you want to be. Otherwise, it probably won't turn back on again.

 

[amalik]

Depending on the theoretical approach you subscribe to, electrons can flow one way or the other.... [MENTION=102597]IBallEngineer[/MENTION] can discuss the details....interesting discussion over a beer but regardless, you are correct, standard automotive practice is to disconnect the negative first and re-attach it last.

Buckaroo

oh, i've heard about it and read about it on the interwebs.

'electrons' (which are negative charge) physically flow from negative terminal to positive.

'current' direction flows positive to negative, this one i think is 'theoretical'.

in auto world, we made it easy by agreeing on a 'convention', so agreed on - to + is my understanding.

 

[RS Dude]

With 306k miles on my original alt. that is working perfectly, I did replace my brushes at around 260k. They had plenty of meat left, although one brush was worn much more than the other. The brush set was a whopping $3.00 or so at the local autoparts store. Not necessary for overpriced Toyota Stealership prices.:bounce:

 

[pauldub]

oh, i've heard about it and read about it on the interwebs.

'electrons' (which are negative charge) physically flow from negative terminal to positive.

'current' direction flows positive to negative, this one i think is 'theoretical'.

in auto world, we made it easy by agreeing on a 'convention', so agreed on - to + is my understanding.

Physicists talk about "electron current" and the rest of the world (including EE) uses "conventional current".

 

[19963.4lsr5]

I was taught electron flow in my navy GSE schools. Negative to positive current flow. They also touched on the positive to negative hole flow theory.

I believe the negative first approach to prevent shorting the wrench to metal and causing a spark over someone getting electrocuted. There's no way you can get electrocuted with 12vdc.

A long time ago OSHA set the standards for high and low voltage. 24v is the margin above is high and you can get hurt 24v and below is low voltage.

Edit: I believe it's also to prevent sparks near the battery. You do not want sparks near a lead acid battery.


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