Date:         Mon, 31 Oct 2011 09:59:04 -0400
Reply-To:     Larry Alofs <lalofs@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Larry Alofs <lalofs@GMAIL.COM>
Subject:      Re: Alternator Troubleshooting
In-Reply-To:  <4EADFEE5.6030009@charter.net>
Content-Type: text/plain; charset=windows-1252

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
>>
>