If you have an alternator that is showing a light or nor performing
properly - of course first check it out. Next step short of buying a new
one - take it somewhere and have it bench tested. If it comes back bad -
check those brushes and replace if worn - then re-test the thing. Many
times the alternator will then test good.

  I have three vans. I had alternator issues and two were down. I took
them off the vans plus a used spare in a box - over to my FLAPS and they
benched checked all three. All three bad. At the time, I didn't have the
money to buy rebuilt alternators - so I popped the rectifier/brush
holder out  and usre enough - all three had completely worn out brushed.
I then put new rectifier/brushes in all of them. Took them back to the
FLAPS. Two alternators worked, the third didn't. But, for just a few
dollars I was able to get all three vans back up and running.

Under most circumstances I would not buy an alternator that tested bad
until I checked out the rectifier/brushes situation. Like I said before
- $15 vs $125 or more for a rebuilt.

Just my $0.02.

John

John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com

On 10/31/2011 8:59 AM, Larry Alofs wrote:
> I once took a questionable Bosch alternator from a SAAB 900 to 4
> different FLAPS in the Chicago area for bench tests.
>    Two places said it was good; two said it was bad.  They used various
> types of machines, some computerized, some not.
> The last place seemed the most professional and knowledgeable and they
> said "bad".  I bought a rebuilt from them and they were right.
>
> Larry A.
>
>
> On Sun, Oct 30, 2011 at 9:50 PM, John Rodgers<inua@charter.net>  wrote:
>> When alternator lights start showing in any stage of light-up - after
>> checking all leads, connections,  VOM meter readings, etc, BEFORE
>> putting in another alternator, I pop the rectifier/brush holder out and
>> see if the brushes are worn out. Most times that's the problem. Replace
>> and you are on your way. I keep a spare set in my emergency parts box.
>> $14-$15 or so beats the heck out of $125 or more for an alternator. If
>> you have your alternator benched checked at your FLAPS and it shows bad
>> - DO NOT believe them. Put in the spare rectifier/brush holder with new
>> brushes - then have them check it. Chances are pretty darn good your
>> alternator will now check good!  It may not check good - but it also
>> may. Personal experience with my FLAPS.
>>
>> I do go to the trouble of cleaning up the copper contact surface in the
>> alternator where the brushes ride with a little piece of worn-out
>> wet/dry sandpaper by holding the paper against the copper surface and
>> simply turning the shaft. Doesn't take much. If there are bad ridges and
>> grooves in the copper - then the alternator probably should be replaced.
>>
>> You can get away with this once in the life of alternator, but when you
>> go to do it the second time, it gets really dicey and will probably fail
>> shortly after the doing of it.
>>
>> John
>>
>> John Rodgers
>> Clayartist and Moldmaker
>> 88'GL VW Bus Driver
>> Chelsea, AL
>> Http://www.moldhaus.com
>>
>>
>> On 10/30/2011 5:30 PM, Gregg Carlen wrote:
>>> Well, turns out to have been a bad alternator after all.
>>>
>>> I found a reference online that said to check for continuity across the
>>> two contacts whet the brushes touch. After removing to voltage
>>> regulate/contacts, sure enough; no continuity on the contact points. Double
>>> checked against the rebuilt one i just got from FLAPs and it showed
>>> continuity.
>>>
>>> Ran down to the local Army base to borrow their impact wrench and swapped
>>> the pulleys.
>>>
>>> Installed the remanufactured alternator, started the van and 'presto', the
>>> battery light is off.
>>>
>>> Voltage between terminals B and D remained about 7V, but the B to housing
>>> and D to housing showed 13.4V. Same at the battery connections.
>>>
>>> Back in business.
>>>
>>> On Oct 30, 2011, at 4:06 PM, Roger Whittaker<rogerwhitt1@GMAIL.COM>
>>>   wrote:
>>>
>>>> Dear light up your life
>>>>
>>>> Been my experiance with a variety of vehicles that those symptoms lead
>>>> to a new alternator if the wires are all I'n place
>>>> Good luck
>>>> Regards
>>>>
>>>> On Sunday, October 30, 2011, Jim Felder<jim.felder@gmail.com>    wrote:
>>>>> I quickly realized
>>>>>
>>>>>> that the pulley�s were different between the alternator in the van and
>>>>>> the
>>>>>> rebuilt one in the box, so no-go for a quick and easy swap since I
>>>>>> don�t
>>>>>> have an air compressor strong enough to power an air-wrench to �bump�
>>>>>> the
>>>>>> retaining nut on the pulleys. Tried holding it with a vice and such,
>>>>>> but
>>>>>> really it�s on there tight.
>>>>>>
>>>>> You can hold the alternator body in a vice, gently and padded with
>>>>> cardboard, and hold the pulley with an oil filter strap wrench while you
>>>>> put a socket on the nut.
>>>>>
>>>>> Jim
>>>>>
>>>>>> So, some quick testing with a voltmeter:
>>>>>>
>>>>>> Test 1: with the engine running, I put my positive lead on terminal B
>>>>>> and
>>>>>> the negative lead on terminal D. The voltage was 7.1V. Battery light
>>>>>> still
>>>>>> on dash.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thinking this is a bad voltage regulator or brushes, I pulled the
>>>>>> voltage
>>>>>> regulator out. A little grimey at the metal contacts, but the brushes
>>>>>> looked fine. Cleaned the grime off and re-installed the regulator.
>>>>>> Restart
>>>>>> the engine and check voltage across terminals B and D and I get 7.1V.
>>>>>> Battery light still on dash.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Just for kicks, I pulled the regulator out again compared it against
>>>>>> the
>>>>>> one in the new alternator from FLAPs and they look identical
>>>>>> physically.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Test 2: Installed the new voltage regulator into my old alternator.
>>>>>> Started
>>>>>> the engine and tested across terminals B and D and I get 6.9V. A few
>>>>>> other
>>>>>> measurements at this point (wish I had taken them in previous tests):
>>>>>>
>>>>>> Terminal B to alternator housing: 11.75v, dropping to 11.5v after about
>>>>>> 30
>>>>>> seconds
>>>>>>
>>>>>> Terminal D to alternator housing: 4.57v
>>>>>>
>>>>>>
>>>>>>
>>>>>> So, given that information and testing, I�m thinking either I have a
>>>>>> bad
>>>>>> alternator (diode, perhaps) or I�m chasing down the wrong path
>>>>>> altogether.
>>>>>>
>>>>>>
>>>>>>
>>>>>> One other caveat to mention: on my original alternator, the suppression
>>>>>> condenser was not mounted the same as the new alternator from FLAPs
>>>>>> (which
>>>>>> was connected to terminal W and the alternator housing). Mine has had
>>>>>> the
>>>>>> connector cut off and mounted to Terminal D, and the condenser itself
>>>>>> had
>>>>>> the hole enlarged and mounted to terminal B. Don�t know that this would
>>>>>> cause an issue, but thought I�d mention it. It�s been this way since I
>>>>>> acquired the van earlier this year.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Any thoughts or advice on other things to check? Or, next steps to
>>>>>> take? Do
>>>>>> I replace the alternator at this point (find a way to swap the pulleys
>>>>>> or
>>>>>> get a replacement one with the correct pulley)?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks in advance!
>>>>>>
>>>>>> Gregg
>>>>>>
>>>>>>
>>>>>>
>>>>>> 91 Westy (Blueberry)
>>>>>>
>>>> --
>>>> roger w
>>>>   From Proverbs:
>>>> Under three things the earth trembles, under four it cannot bear up: a
>>>> servant who becomes king ...
>>>> ----------------------------------------------------------
>>>> Explore printed work at: http://www.prliving.ca/
>>>> View the growing list of video work at:
>>>> http://www.youtube.com/user/LastonLastof#g/u
>>>>
>>>> http://www.prpeak.com/articles/2010/11/29/multimedia/video/doc4c62e5f80d228504902172.txt
>