How I Fixed my Alternator

ajbremer

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Tuesday - November 22nd, 2022

NOTE: I believe this all happened because the battery was hooked up backwards. I'm surprised it didn't do more damage than what I currently know.

Here's what I did to fix the bad alternator on my 1989 Bronco 2 XLT:

I received the car with the battery cables hooked up backwards, it had been this way sitting for months. My first thought was that all kinds of wiring has been burnt out, fusible links, fuses under hood and dash, fried alternator, and the list goes on. First I hooked the battery up properly and then checked it, it only had 11 volts. Then I tried to jump it but nothing at all happened when I turned the key to the start position (the gauges were working though).

My first thought was the starter solenoid. I took a ***** driver and jumped it across the relays 2 positives and it started to crank...ok, a good sign. Then I checked the 'S' wire above those 2 positive terminals for voltage when the key was turned to the on position...it had voltage. Ok, new starter solenoid needed.

Bought a new starter solenoid for $20, put it in, and it started...cool! Next, I checked to see if it was charging and it was not. Removed the alternator to get it tested and it tested bad. Went to a yard and bought another one for $35 but it had a different type of pulley on it. I tried hard but couldn't get the 15/16's nut off of either alternator, they are on there super tight.

In the past I have taken apart alternators and fixed them so I first took the bad one apart. Removed the voltage regulator to look at the brushes and they were almost totally gone (I'll put pics at bottom). Then I removed the case on the original 'bad' alternator to look inside. There was much black soot and the terminals looked burnt. I also did all of the above to the alternator I got at the yard, it looked much better but its brushes were really short but much better than the bad one.

So here's what I did next: I took the original alternator front cover (pulley, cover, and rotor) and then took the back of the yard alternator (stator, rectifier, and voltage regular) and put it all together. I used a small drill through the hole of the voltage regulator to hold in place the brushes while inserting into the cover. I must mention that I cleaned and sanded a little on the rotor and stator and the shaft where the brushes brush up against. Then I put it in and guess what...it charges most excellently!

Ok, I can and should do two things - either just go ahead and buy the Orielly's $120 new alternator or I can buy a $5.00 brush kit and put new brushes in. I need to mention that I'm out here in the Arizona desert and a ride to the auto parts store is around 100 miles round trip so I always do what I can at home till I can get out.

I'll attach pics of my play time, thank you people!
 

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goodO1boydws

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That sounds fairly high for a low output alternator-for an older, domestic vehicle.

You want something easy that has new parts in it, is delivered, and has a warranty?

Try checking the pricing on this page for a reman. alternator with a decent or warranty at rockauto.com


You'd have to pay tax and shipping, but the cheapest one shown includes a 1 year warranty that covers jumps starts and towing.
For $26.00
That price INCLUDES a $6.00 core charge, so you wouldn't even need to send one back.

(The NEW ones start at $52.00)
-----------------------------------------------------------
For future reference-some tips on getting an alternator pulley off.

On a part that's used, the rust adds a LOT to the breakaway torque so those are almost always a LOT harder to get off than a new one torqued to the same original tightness. Without using penetrating oil it can be extremely difficult to get them off if you don't have access to an impact wrench, but there are simple ways to increase your odds of success without potentially damaging anything.

(Some of the following ways can be used on other nuts.)

1. ON the vehicle.
Tighten the alternator belt as much as possible-so it won't slip and to keep the alternator parts from rotating, roll up and stuff a rag in the gap between the belt and pulley, on the side that will wedge it into the pulley when you try to loosen the nut. Then take penetrating oil/rust buster and squirt it at the base of the nut. Let it sit for at least 1/2 hour. Use a good straight or OFFSET box wrench. (one that size nut is typically over a foot long)
Once in a blue moon that's all it takes.
Let it sit overnight and try again-you may get lucky.
If you don't
Give the wrench a few good whacks with a heavy hammer until the nut begins to loosen. If you did break it loose and its taking a long time and many whacks to get it to move any distance, put the rag on the opposite side of the pulley and TIGHTEN the nut. Then repeat the process adding penetrant. Each cycle that you do this the nut will get easier to move outwards or will rotate further with the same effort.
(This method nearly always works.)
You could also use a breaker bar, and you MAY not need the whacks. But when increasing the tool length and/or number of tools or parts between the nut and the hammer, it reduces the impact energy that gets to the nut, so you lose much of the advantage of a longer handle. And risk damaging the breaker bar as they are designed for TORQUE, not hard impacts

2. OFF the vehicle:
Use an impact hammer.
MANY times that alone works.
If that doesn't work immediately,
Apply penetrating oil, let it sit for at least a couple minutes (longer is better)
Try again.
If it still wont come off:
If the alternator has accessible fins, lay it on the floor and have the fins press into a piece of soft wood. Make sure the wood is pushing against something heavy so it doesn't move when trying to unscrew the nut. Put one foot on the alternator for control.
Use an impact hammer/wrench.
Do the in and out routine if its tough to move the nut.
If it still doesn't move, let everything rest, apply more penetrant and let it sit overnight.
(This way has NEVER not worked for me)

3. IF THAT DOESN'T WORK:
Apply freeze off spray and quickly try to get the nut off.
If the nut is not moving, heat the nut with a hair dryer until its significantly warmer than room temperature (Do NOT use a heat gun) quickly hit it with the freeze off, and try to loosen it again. This gives you a bigger temperature swing.

4. ONLY IF THAT DOESN'T WORK, juice it up with more penetrant heat the nut with a pinpoint flame propane or butane type hand torch (NOT A WELDING TORCH), and try the loosening/tightening routine.

Too much heat can destroy an alternator, so your goal is to heat the nut and as little as possible of anything else so the nut expands and the shaft doesn't. Obviously you don't want to do this with a plastic fan alternator and you want/need to keep the fan, as it will almost certainly deform.

5. Use a Dremel-type tool to grind or cut a narrow slit into the nut down ALMOST to the threads JUST wide enough to use a cold chisel in the slot-TO WIDEN THE SLOT ONLY. That stretches the nut. (You're duplicating a nut splitter) In rare cases this needs to be done on more than one flat of the nut. Even if you do damage threads in a slit pattern, with a shaft this large in diameter its not significant.

Some people (like me) after wire brushing or deburring or polishing the shaft if necessary, put a TINY bit of antiseize on an alternator OR power steering pump shaft, before running the nut back on or pressing the pulley on. They're usually the ones intending to keep the vehicle for a long time.
 
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ajbremer

New member
Joined
Nov 19, 2022
Messages
9
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Location
Arizona
That sounds fairly high for a low output alternator-for an older, domestic vehicle.

You want something easy that has new parts in it, is delivered, and has a warranty?

Try checking the pricing on this page for a reman. alternator with a decent or warranty at rockauto.com


You'd have to pay tax and shipping, but the cheapest one shown includes a 1 year warranty that covers jumps starts and towing.
For $26.00
That price INCLUDES a $6.00 core charge, so you wouldn't even need to send one back.

(The NEW ones start at $52.00)
-----------------------------------------------------------
For future reference-some tips on getting an alternator pulley off.

On a part that's used, the rust adds a LOT to the breakaway torque so those are almost always a LOT harder to get off than a new one torqued to the same original tightness. Without using penetrating oil it can be extremely difficult to get them off if you don't have access to an impact wrench, but there are simple ways to increase your odds of success without potentially damaging anything.

(Some of the following ways can be used on other nuts.)

1. ON the vehicle.
Tighten the alternator belt as much as possible-so it won't slip and to keep the alternator parts from rotating, roll up and stuff a rag in the gap between the belt and pulley, on the side that will wedge it into the pulley when you try to loosen the nut. Then take penetrating oil/rust buster and squirt it at the base of the nut. Let it sit for at least 1/2 hour. Use a good straight or OFFSET box wrench. (one that size nut is typically over a foot long)
Once in a blue moon that's all it takes.
Let it sit overnight and try again-you may get lucky.
If you don't
Give the wrench a few good whacks with a heavy hammer until the nut begins to loosen. If you did break it loose and its taking a long time and many whacks to get it to move any distance, put the rag on the opposite side of the pulley and TIGHTEN the nut. Then repeat the process adding penetrant. Each cycle that you do this the nut will get easier to move outwards or will rotate further with the same effort.
(This method nearly always works.)
You could also use a breaker bar, and you MAY not need the whacks. But when increasing the tool length and/or number of tools or parts between the nut and the hammer, it reduces the impact energy that gets to the nut, so you lose much of the advantage of a longer handle. And risk damaging the breaker bar as they are designed for TORQUE, not hard impacts

2. OFF the vehicle:
Use an impact hammer.
MANY times that alone works.
If that doesn't work immediately,
Apply penetrating oil, let it sit for at least a couple minutes (longer is better)
Try again.
If it still wont come off:
If the alternator has accessible fins, lay it on the floor and have the fins press into a piece of soft wood. Make sure the wood is pushing against something heavy so it doesn't move when trying to unscrew the nut. Put one foot on the alternator for control.
Use an impact hammer/wrench.
Do the in and out routine if its tough to move the nut.
If it still doesn't move, let everything rest, apply more penetrant and let it sit overnight.
(This way has NEVER not worked for me)

3. IF THAT DOESN'T WORK:
Apply freeze off spray and quickly try to get the nut off.
If the nut is not moving, heat the nut with a hair dryer until its significantly warmer than room temperature (Do NOT use a heat gun) quickly hit it with the freeze off, and try to loosen it again. This gives you a bigger temperature swing.

4. ONLY IF THAT DOESN'T WORK, juice it up with more penetrant heat the nut with a pinpoint flame propane or butane type hand torch (NOT A WELDING TORCH), and try the loosening/tightening routine.

Too much heat can destroy an alternator, so your goal is to heat the nut and as little as possible of anything else so the nut expands and the shaft doesn't. Obviously you don't want to do this with a plastic fan alternator and you want/need to keep the fan, as it will almost certainly deform.

5. Use a Dremel-type tool to grind or cut a narrow slit into the nut down ALMOST to the threads JUST wide enough to use a cold chisel in the slot-TO WIDEN THE SLOT ONLY. That stretches the nut. (You're duplicating a nut splitter) In rare cases this needs to be done on more than one flat of the nut. Even if you do damage threads in a slit pattern, with a shaft this large in diameter its not significant.

Some people (like me) after wire brushing or deburring or polishing the shaft if necessary, put a TINY bit of antiseize on an alternator OR power steering pump shaft, before running the nut back on or pressing the pulley on. They're usually the ones intending to keep the vehicle for a long time.
Thank you Good01boydws, that's a bunch of great information sir!
 

goodO1boydws

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Thank you Good01boydws, that's a bunch of great information sir!
You're welcome.

About the nut splitter:
I should have included that its not often that there is enough access for one, the nut is too large for some splitters and unless you're a tool j-u-n-k-i-e (which I've been accused of being) most people don't have them.

-------------------------
I noticed that something in your post didn't get past the dreaded filter.
S-c-r-e-w-driver will.

The automatic "offending word filtering" program on this site can be a pain.
 
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