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Alternators anyone?

Turbo Joe

KING OF TBOT
Joined
May 16, 2010
Location
bend oregon
I am replacing my alternator and there is a bonus wire. On the lead going to the plug thingee in the back, should there be 2 wires? Did one break off?The extra wire is in the same housing as the other two and has no fitting on the end
 
Here's a picture of the wiring on my 745. However, it's the same as the 245, at least between my cars... (I'd get ones of the Bosch 100A in my 245, but I don't feel like crawling under the car for a good shot of the wiring.)

IMG_20121206_161333.jpg


And a sort-of closeup of the little red lead that is bundled with the big, gnarly one.

IMG_20121206_161403.jpg
 
Crawl bitch!
I think I have it figured out. Thanks.

No I lied. I copied this from another page. I have a blk wire with no connector. Where does it go?

B+ is the large terminal. That connects to the battery + terminal via it's connection to the large battery + connection on the starter. They are connected together on the large starter stud.

D+ is the push on terminal for the exciter or charging light. A small red wire that goes to the dash cluster.

Case ground is a blue wire that connects to one of the outer case studs to provide ground for the alternator. It connects from the case stud to a mounting bracket bolt on the block.
 
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Joe,

There is no extra wire. On a 240 alternator there is a stud that has a terminal on it that the exciter wire connects to. The terminal on the 80A 240 alternator is a spade type terminal. Just unplug the exciter wire from that spade connector and attach it to the spade terminal that is recessed into the back of the 100A alternator. The power/charge wire is obvious enough. The ground terminal is a small stud that has an 8mm nut on it just like your 80A 240 alt. It just looks a bit different. Everything is essentially the same between the 2.
 
I understand what you are saying. But, there is a small black wire there. It is wrapped up in the same wire protector as the alternator wires. No obvious place for it to go. It is broken and frayed

W
photobucket-37675-1354835046255.jpg
 
I understand what you are saying. But, there is a small black wire there. It is wrapped up in the same wire protector as the alternator wires. No obvious place for it to go. It is broken and frayed

W
photobucket-37675-1354835046255.jpg

*OIL PRESSURE SWITCH* (just to the rear and on the block....:nod:
 
Be careful which male spade ya plug onto. Might ant to check the greenbook, or maybe cleanflametrap.com

I believe...that the black wire is for OP sender for the ever popular OP idiot light. I'd redo some of that wiring f I were you. Especially the frayed, small red wire. That is bad ju-ju there.
 
car is a 93 245a the parts car is a 90 740

two main Qs for those who do not want to go too deep

what should a good alt read at the two red posts
I get 13.4v at idle 12.8v off on the big red
but oddly 13.8v on the small red post

and when starting the volts drop to 11.5v
then slowly about a 0.01 per second climb to 13.4v

and will a different looking 940/95 alt be a eazy swap into a 93 245a

the alt was not charging or intermittently and weakly
and battery was weak leading to no start hot
so I charged the battery
and the problem recurred
so I swapped in a parts cars 90 740 alt that was working ok [bad trans]
and took the car to autozone to check the system

the machine reported good battery surprise
but no charge from the alt
exactly the reverse of what I expected to hear
battery reads 12.8v with the car off and 13.4v running low but producing some current !
oddly no change in volts when rev-ed off idle
the big red post on the back of the alt also reads 13.4v running
BUT oddly the small red post reads 13.8v [thought that was the coil winding input ?]
is that normal or not ?

they called the voltage reg bad and wanted $80 for a new one
the voltage reg looks like the diode + brush holder on the back of the alt
not a black box or just a voltage reg

two bad alt's makes me think a wiring problem ?

the only clue so far to wiring on to the alt
is a small/thin black wire bundled with the big and small reds on the 240
BUT no lug or obvious place for it to go to ?
and no similar wire on the other car
note not the larger blue wire that has it's own post
where should that black wire go


both the 245/93 and the 740/90 alts looked like the same unit
I also have a 940/95 parts car but that alt looks totally different
round nose totally different shaped
will that 940/95 alt fit on my 245/93 ?
 
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^ check the blue alternator ground cable. fastens to a through bolt on back of alt & then it fastens to a MM bolt. Known to break due to stress/broken MMs and just old age. Also sounds ike alt might need a rebuild. Check all alt wiring coming out of the main engine wiring harness first though
 
car is a 93 245a the parts car is a 90 740
they called the voltage reg bad and wanted $80 for a new one
the voltage reg looks like the diode + brush holder on the back of the alt
not a black box or just a voltage reg

The voltage regulator brushes are a very, very common failure on our cars, with the Bosch alternators. Between three Volvos, I've replaced two regulators and two sets of brushes in the past year. (The 745 had it done twice, because the "OEM quality" crap regulator the local parts house gave me, when I specifically asked for Bosch, only lasted three months. Needless to say, I pitched a big enough fit to get a new Bosch regulator.)

I actually switched the 745 over to the 100A Denso, just because it has easier brushes to change, dropped the 100A Bosch into the 245 and now have a Bosch 80 on the desk with a rebrushed regulator.

Enough rambling, though. Here's the fix. Pop the regulator off of there, go to your local alt shop and drop $20 or so for the guy to replace the brushes. Or, you can buy the brushes yourself, drill out the old ones, solder the new ones in and go, go, go.
 
I have two alt's out of the car

with DVOM how can I test if they are good or need to be fixed
 
I have two alt's out of the car

with DVOM how can I test if they are good or need to be fixed

http://www.k-jet.org/documents/greenbooks/200-series/
TP30729-1 GREENBOOK "charging systems"

If *I* were doin' it...I'd head for the loacl parts house that has
a starter / alernator "dyno"...and let THEM do DYNAMIC / LOAD
and OUTPUT TESTING.... (and you'll STILL only be about 90% sure....
DAMHIKT!! :oogle: )
 
from your link
77+46 core no name rebuilt

bosch 161+90 core rebuilt

I guess 55 was a sale or a while ago

Was a couple years ago. I'll see if I can find the one I bought....
 
from your link
77+46 core no name rebuilt

bosch 161+90 core rebuilt

I guess 55 was a sale or a while ago

I'm taliking just the *OEM BOSCH Voltage Regulator* (has the brushes in it) The aftermarket/made In China voltage regulators are 15 volt, and I had poor service out of them . They are junk IMO.

FWIW, the OEM Bosch volt. regs. are set to 14.4 volts. Bosch Volts regs are not available at AutoZone, Advance Auto etc. At least not when I checked them.

OEM Bosch Voltage Regulator 14.4 Volt , for my 1991 240 Bosch 80 amp Alt......from usautoparts.com............. $30.95 plus shpg.


LINK> http://www.usautoparts.net/catalog/...Dx=mode+matchallpartial&Ntt=voltage+regulator
 
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Okay......new annoyance. The pivot bolt fits fine as do the belts. The tensioner bolt does not fit. The original has a square head that fits into a square hole in the housing of the alternator. This makes the old bolt to short to fit in the new alternator housing. Also the new one is smooth and flat. No square hole. What size, strength and yada yada bolt do I need?
 
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