ALTERNATOR FIX (Battery Light On): Inst. w/ pics

bandi · Oct 6, 2008

To read the original full thread and post questions/comments on this topic, please go to http://www.fjcruiserforums.com/foru...e-performance/70947-battery-light-possible-fix-your-alternator.html#post1149310

Well, I fixed my own alternator this morning.

After I left my house to go get coffee from the local WaWa, I had the battery symbol idiot light come on, really a erratic flashing, it seemed to be effected by the rpm range some too, and at some points, it would be steady on.

I looked at the voltmeter, and it was still in the charging range, but at the bat' light illuminated, the needle would dive just a tad. I pulled over and checked the bat' terminals and they were clean and tight, I also checked the stock bat' sight window, and it was blue, which means it was okay, too.

Now, I pulled ok the glove box manual for yucks, and the only thing they wrote under this light was to contact Toyota right away. This was a little worrisome to say the least. I am thinking that this could end up costing some bucks. My thoughts based on the the symptoms are that the alternator has gone bad in some way or the regulator was not distributing the power correctly.

I opened the hood and decided to do a small test to make sure my guess was right, so I took a can of brake cleaner, and sprayed though the openings in the alternator to see if it had any effect, and it did, the light went out in the dash, but soon came back on after 10 minutes, but it proved my theory.

Now being that I have used my FJ for offroading, I knew this wold not be covered by warranty due to the flash muddy water storms my FJ has seen, even if it was not related.

I did check on the price for a new alternator just for yucks $478.05, a tad bit pricey, But I don't want to just toss that cash out just yet, so I figured I would pull the alternator out and disect it a little, so below is the outcome.

First you need to remove the Alternator from the FJ. To do this, you need to remove the battery wires from the battery using a 10mm socket or wrench, then use the same for removing the battery hold downs, and then remove the battery itself along with the plastic tray. This needs to be done in order lift the alt' up through the opening.

Next, remove the two of the push pins holing part of the rubber flap in the wheel well, one pin in the shock tower, and one in the frame rail, so you can access a few of the wire harness bracket bolts.

Then using a 10mm socket to remove the two bolts from the side of the alt' and one at the side of the battery mount base, which will allow movement in the harness necessary for the alt' to have enough room to get through.

You will also need to remove the wire connections from the alt', one is a 4 wire connector, which you need to squeeze the tab with your finger to release it and then unplug it.

The second on has a gray round cover which snaps on, which can be removed by placing a small flat tip screw driver in one of the slots and pry slightly to release it, then use a 10mm socket to remove the nut holding the wire on.

You can see the connection point here below.

Next, using a 10mm socket, remove the engine top cover so you have room to get release to tensioner for the serp' belt.

Next, you will need to use a 14mm socket to release the tensioner for the serp' belt and remove the belt from the alt' pulley. In the picture below, you can see the belt stuffed forward near the fan area so you have room to work.

Now use the 14mm socket and remove the two bolts that hold the alt' in place, these are both accessed from the front of the alt area, one towards the bottom and one on top, again, you can see the two hole locations in the photo below.

Once the bolts are remove, you will need to move the alt' up and down and wiggle it in and out to get it free, and maybe use a pry bar between the engine and the alt, to pry outward a tad.

Once it's free, you can maneuver it upward and out.

(Continued in the next post . . . )

bandi · Oct 6, 2008

Re: Battery Light on ?... Possible FIX for your Alternator !...

THE DISECTION!!

Now, stand the Alt' on it's pully, and remove the three 8mm nuts that retain the black plastic cover from the back of the Alt', then lift it off.

Now you can see where the brush pack location is in the middle and the sealed electronic module on the right, both are brown in color.

Now you will need to remove the brush pack using a Phillips tip screw driver to remove the two small screws that hold it in place.

Once I took off the brush pack, I knew what the exact problem was with the alternator... The brushes are spring loaded to keep them riding against the shaft, so the current can be transferred from the shaft to the module.

Here is the brush pack, and notice the brushes are sticking all the way in the pack housing... When they are stuck in this position, they cannot make proper contact with the shaft, so that is the reason I had the bat' light on in the dash.

Now this is the way they should look, notice how far the springs outward when they slide freely in the pack housing.

Notice the fogged plastic cover, this had to be removed to access the brushes... I did this by pushing in on the fogged plastic to release it, and pulling it off with my finger in the center.

I then used some spray brake cleaner to loosen them up, and then using a small wire to use as a hook to pull them out. You can see here, where I put the wire into the hole and pulled outward. Just be careful not to damage the wires at the back of the brushes.

Once they were outward, I then sprayed more cleaner in them to clean out the dirt that was the cause of this problem. I them coated them with a thin coat of tune-up grease, and pushing them in some to lube everything up so they would spring out on there own.

I then sprayed the entire alt' with brake clean and used an air compressor to clean it out and clean it up as much as possible.

After that, I cleaned up the shaft and put a real thin coat of tune-up grease on the two connection areas where the brushes make contact.

Although, after the fact, I must say, it is not really recommended to put this on the armature as it will allow dirt and such to build up and stick to it.

Now with the brush pack freed up, press the fogged plastic piece back onto the brush pack. You will then need to use the wire again, this time straight, to hold the brushes in while you slide the pack over the shaft.

This is accomplished by sliding it through the hole shown here:

Now hold the brushes in, and slide the wire up through the hole till it is through the hole at the other end.

Now place the brush pack back over the shaft, and put the two screws back in.

Then pull the wire out, which will release the brushes.

Now reinstall the back plastic cover with the three 8mm nuts, and put the alt' back into the truck, put the serp' belt back on, the wire connection, the flap, battery, and engine cover.

DONE!!

Started it up, drove around for a bit, no light on and the voltmeter shows a steady charge.

I hope this helps someone out. I will be ordering a new brush pack setup to keep with me at all times!!

ALTERNATOR FIX (Battery Light On): Inst. w/ pics

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