Alternator ?'s

[kamzcab86]

I've suspected that my Cab's alternator isn't working at its full potential. I put it to the DVOM test and sure enough, it's slowly going bad and will need to be replaced in the (near) future. This is a rebuilt alternator (brand unknown, bought from a local import parts store) and is about 4 or 5 years old. My questions are:

1. Where do you all buy your alternator's from? Local, online?
2. How long have your rebuilt alternator's generally lasted? (The original alt. lasted over 10 years.)
3. Is Bosch the best brand to get?

[Briano1234]

Well, I go Bosch for the new one, but if you bought your alternator as a rebuilt it may be under that LLW (Life Time Limited Warranty)......so Check it out.

Just be sure that you have it tested prior to leaving the store.

But Wait Theres More.

Remove the Positive cable from the battery.
Loosen the Alternator belt.

Remove the Power cable and the exciter wire from your Alternator.
Remove the 2 phillips screws holding the regulator assembly from the Alternator.
Look in to the hole....
See the commutators (little copper pads?) You can take a sewing pin and Gently Scrape the old carbon from between them.
After those are clean, you can buy alternator/motor cleaner at a parts store. Spray off that built up carbon...when dry clean each of the little pads with a pencil eraser... Spray clean, allow to dry and replace the regulator assembly....

If it then measures correctly, a little cleaning is all it needed.

[kamzcab86]

Sounds easier to just get a new alternator. I'll take a look at it's possible carbon build-up this weekend.

I looked and it is indeed warrantied for life. Oddly though, even the receipt doesn't tell me what brand of alternator it is, and the alt. itself has no identifying info on it, not even its amperage.

[Briano1234]

The two most common types are Motorola, and Bosch.. I would say it's a crap shoot.

[CalAltaDubber]

Actually, Brians comments about removing the voltage regulator and cleaning the comutators is a good one. It is also not hard to do!

While you have it out, it is a good time to measure the brushes. If they are any less than 5 mm replace the regulator. should cost about $15. for a new one at your local auto parts store.

The brushes on the regulator are the part that wears out bucuase they ride on the rings of the alternator.

It's only two small screws to replace it, and the alternator can remain in the car. I do recommend disconnecting the battery before removing the Voltage regulator.

Replacing the whole alternator, I usually go to Pick 'N' Pull. Any alternator from a MK I or MK II will fit. I assume you have AC so you will need to find a 90 Amp. version (standard on AC cars). The 65 Amp. (from non AC cars) won't handle the demand of the AC.

My '87 still has the alternator that was delivered with the car (Vlaeo, French made). The voltage regulator has been replaced several times. The problem with this one is the regulator is different from the regulators in the Bosch alternators that VW usually provided. I have managed to aquire a couple of spares, because they are becoming very hard to get.

I'd assume that any alternator will do, but Bosch was the one that VW usually installed

[kamzcab86]

It looks to be a Bosch, but...

I did remove the regulator several months ago (didn't know then about the carbon build-up), and the brushes were within specs; I think they were around 6 or 7 mm. I'll have to measure them again. Although the battery is in good shape, the alternator isn't even producing 13 volts, and with accessories running the volts drop even more which is why I'm leaning towards BAP just giving me a new one.

[Moljinar]

Alternators rarely good bad slowly. They usually die a horrible noisy death. If it's going bad slowly it's probably the regulator or the brushes which are built-in to the regulator. Regulators are small little items that tend to follow me home after visiting junkyards. Two phillips head screws and it's in your hand. Brian's instructions are thorough but if you can manage to work closely to hot terminals without welding your screwdriver to your car you can change your regulator by simply removing it and replacing it.