90 Corolla alternator repair?

[BennyProphane]

Hi, I have 90 corolla and the alternator has been going out for about 2 months. the battery+brake lights both come on, and that's when i know it's stopped working. all i have to do is tap the alternator with something to get it going again. for this reason i havent worried too much about it, until it gets alittle warmer outside, to replace it. I have a used one ready to put in, but i'm wondering if I can easilly repair it, similar to what people do to repair the starters in these cars? I believe they replace the terminals inside. Of course I know it's different than a starter, but by the way it's acting, it may be a similar repair. When I tap it with anything as small as a screwdriver, it starts working again 100% of the time. Thanks for any suggestions.

[SCT]

I would just take it out and pop in a whole "new" one. Unless $$$ is an issue. Roughly $70 to $120 i think for alternators.

[BennyProphane]

Thanks SCT, but I have already picked up a used one, and I'd rather not spend the money on a new one at that time. I was planning on putting in the used one (one of these days) and was wondering if the one that's going bad could be easilly repaired, or if i should throw it away. thanks again.

[RogueMoog]

I've read here & elsewhere that you can have an "auto electric shop" rebuild your alternator for less than the cost of buying a new or remanufactured alternator. I don't know of any shops like that around me, though.

Also, everyone has been telling me that some auto parts stores can do free charging system checks. I'm planning on taking my wagon to get checked sometime soon. I already had the battery checked a few months ago and it's fine.

I believe the common culprit is the voltage regulator (costs like $43 - $82), when the brake & battery warning lights are on (which is what I've been seeing since December when I replaced the clipped fuse I found under the hood).

[BennyProphane]

Thanks for you input. yea, if it's the regulator, then it may be best to just put used alternators in (unless too many fail), but I get them for $20-$25, so it's prob hard to go wrong with one or two. A core charge on a new-reman is about $40, so instead of giving up my "sometimes" faulty one, I'll just keep that as a backup, and not worry about repairing it now. Although i will prob open it up and just see if any wires have a bad connection. Up until now, i havent worried about getting stranded, because my radar-detection has a voltage meter that lets me know when the battery gets below 10volts, or ? like that. when i have to, i just stap at a station and get out and tap it. it will work until the battery is fully charged. This summer, i'm going to experiment with a alternator shut-off switch, because I know the car gets better fuel milage when it's not working. on one daytime trip, the alternator stopped working and I drove for about half of a tank without the alternator, and on that tank of fuel, I got 365 miles (on winter fuel). Thats prob about 36 miles per gal. usually I get about 320-330 (highway milage) . during the summer, i'll see what it gets per full tank, alrernator not working at all. thanks again!

[90 GP]

Don't know how hard it would be to find a voltage regulator and brushes (or the cost) . Would probably be better money spent to rebuild your original than taking chances on used ones that may not be in any better shape than what now have.

[RogueMoog]

OK, so here's a question. I've got the brake & battery lights coming on when I'm driving, but they don't always come on. I do have two amps in my car now, one for a sub, the other for 6x9s. Anyways before I put those in, I would see these dash lights coming on (or not at all) randomly. Now with the amps, I still get the lights. (I don't think having the amps would make the problem go away, just saying I still see this issue.) I had my battery checked at the end of last year, and then today along with the charging system:





Any ideas why those two dash lights are coming on randomly? Bad ground maybe? Need to do a better check per the FSM for the alternator? Alternator not good enough to power my "extra" audio plus everything else?

[blb]

BennyPhrophane...What's happening in your case with your alternator is your brushes are worn and because they are worn, the spring tension behind them is not keeping them pressed down firmly enough all the time against the rotating armature. When you tap on the alternator and it begins working again, you are reseating the brushes against the armature. All you need to do to fix it is to take apart your alternator, remove the brushes, find an old fashoned hardware store (not the big box stores) or an auto electric shop, buy new brushes, and install them. This should cost less than $3.00. In my experience, I have found that it is extremely rare for the voltage regulator to fail on these cars.

I have found that the rebuilds that the chain auto parts stores sell are of generally low quality and generally don't last very long. A low mileage used OEM one, or installing new brushes in your original is probably your best bet.

[BennyProphane]

Thanks Blb,
I'll check it out as soon as i can get the darned thing off.
I cant get the alternaor off, due to not being able to get a wrench onto the bold which it at the bottom of the alternator. there used to be a tab, or stopper type thing which I guess is supposed to stop the bolt from turning, as you take off the nut from the left side of the alt. anyway, that stopper broke off, and now the way it's situated, it's in the way of placing a wrench/socket onto the bolt head.

so now my idea is the just take the entire alternator housing bracket off of the head. after taking the two top bolts off of the bracket, it wont come off, and i cant see or feel any other bolts which would be holdiing the bracket onto the engine.
Under the alternator is the air compressor, so i dont think anything would be attacked to that.

Does anyone know where any other bolts are, which would attach the alternator housing bracket to the engine?

(1990 corolla 4AFE engine)

Thanks alot.

[nizzehult]

Could be the rectifier as well. My rectifier gave up a few days ago (also a '90 Corolla) and you could even see that one of the diodes in the rectifier was glowing!
The battery light was not on but there was a strange sound from the alternator.
I won't hazzle with it - just replacing it with a used one.
I've seen refurbished alternators for as low as $40 in the US.

[Mr.Nutcase]

I would replace the alternator, On my Corolla the alternator went bad, I
replaced on November, Has worked since
I bought Napa alternator, got for 75 bucks(with shop discount)

[mikejax19]

check the ground wire i had the same issue when i did the head on my 4afe tife you have a loose ground it wont charge right