Alternator fixed itself!

[mabrodis]

So yesterday we were out wheeling, hit a bit of mud, nothing major, then a few good mud puddles, splashed through them pretty good, had a grand time. Got back into town (~10 miles) noticed the light right above the volt gauge was on...and the voltage was lower than normal. So, I started kicking myself and figured somehow I killed the alternator. I started it and disconnected the battery, sure enough, died instantly (I don't think this is a absolutely positive test for a bad alternator, but it confirmed what I wanted to know). So I charged it up with jumper cables from my brother, and drove the 2+ hours home just running off the battery.

Then this morning I pulled the alternator off and took it to a auto parts store, they tested it and it was fine. I put it back in tonight and it's fine, charges perfect. So I'm guessing that the mud/water got into it and was screwing it up, but after it sat all night, it dried out and now everything is happy again? ???

I wasn't worried about having to actually replace it, just pull it apart to clean out some gunk, but didn't even have to do that, although probably should...but likely won't...

So anybody else's alternator fix itself? Rather cool I must say.. I actually meant to start the vehicle this morning before pulling the alternator (to see if this exact thing happened) but forgot, if I had I probably could have saved a ton of time and work, but that's not my style!

Later,
Mark Brodis

 

[Lars]

Not sure what happened to mine but two weeks ago, several of my warning lights lit up in a manner which, according to others here, is a symptom of an alternator issue ... most likely a worn brush set or a loose belt.

I've put about 500 miles on the Cruiser since then and havent had any additional problems. So far, it was an isolated incident.. knock on wood.

I did notice this weekend that when I shift from park to any other gear there is a slight change in the voltmeter reading. Curious.

I've got the replacement brush set from Cdan and going to replace it as PM.

 

[Riley]

A word of caution regarding -

>> I started it and disconnected the battery, sure enough, died instantly <<

I wouild never do this. Electronic voltage regulators hate not having the battery connected. In some designs it's a good way to blow their output transistor which means you would have to replace the module.

I'm not sure about Toy cruisers but I'd avoid doing that test in general.

 

[landtank]

Sounds like another brush set is in order. They are cheap and easy to replace.

 

[DRTDuck]

Mark-

I would pull the alternator and change the brushes. They are most likely worn to where the are almost not touching and will touch/not touch back and forth for a couple of days.

When mine recetnly went bad, I pulled the alternator, took to auto parts store to check. It tested fine. 2 things, 1. moving the alternator around, allowed the worn brush to gain a new position therefore touch. 2. the auto part store tested it at about 3000 rpm. when the brushes are literally a couple hairs short, they will sometimes still conduct with high enough rpms.

I put the alternator back on, thinking it was okay (didn't know any better about checking the brushes then). It stopped working completely 2 days later, 3 hours from home in the middle of the woods at 5 am!

Replace your brushes now, there only about $12.

 

[Rogue]

Replace the brushes or you'll be sorry.

 

[Riley]

Anybody want to guess at what mileage the brushes start to fail at?

post 100K?

 

[DRTDuck]

on 2 recent post, there were suggestions to include it as a regular PM item anyhere from 90K and beyond, most suggesting 100-120k.

based on a variety of variables that can go into wear quickness, i would suggest 90k. for $15 you might as well do it while you doing the rest of your 90k service.

 

[landtank]

You can't judge aternator life by miles. It's wear is on usage and that's where it can get tricky. Do you drive at night with the head lights on alot? Got some big honking stereo amp running? Winch use regularly? Run a battery til she won't work any more? All these things will require use of the alternator and depending on your individual habits you will have your own time line.

I changed out my brushes at 130k. They were only half used. I didn't have a stereo amp, no winch, lots of highway driving during the day and replace my battery every 3 years regardless. So I didn't ask alot from my alternator.

Still at $15.00 it's hard not to replace them. Even sub 90k, if you are having what might be an alternator issue get them changed out.

 

[mabrodis]

Great info guys!!

I'll pull it and replace the brushes (anyone have the part# handy?)..

Mine is at 122K miles, no winch, so I wouldn't expect the alternator to lead a hard life regarding charging.

I have the factory manual, so is the brush-change procedure pretty straight-forward? I looked some online and did not find a writeup...maybe I'll make one when I do mine.

As for disconnecting the battery while running, I'll admit not the best test, I always wondered what the voltage went up to with no battery...hmm...I've done that with lots of cars over the years and haven't killed anything, and every one that wouldn't run, alternator was bad...but I agree it's not the best and probably shouldn't be done.

Thanks a bunch,
Mark Brodis

 

[Rogue]

27370-75060

 

[Riley]

Ok given I'm under 90K and no Winch and light loading, I'll put it off for awhile. Not that I'm worried about the $15, I'm just tired of the PM and want to spend sometime wheeling.

Riley

 

[Eduardo96FZJ80]

Riley.
Or you could do like I do, order stuff and just set it on the garage work bench