Alternator Options - I need Help!! - PeachParts Mercedes-Benz Forum

lino · #1 05-21-2005, 09:23 PM

If any of you already read my other post today, you probably know why I'm typing this one right now.

I want to get a new alternator for my 1989 300ce. Here is some information on my alternator:

Engine ----Model-----Year --------Application ------ Amp kW/HP --- Sys Mf ----Plug Conf. ---- Reman Alt.
3.0l-L6 --- 300CE --- 89-88 ------ Bosch 70A ------- 70------------ BO -------- B15 ---------- AL65X --------(*108)

BO=BOSCH

*108 -BOSCH/VALEO Notice of Interchangeability
This alterantor came as original equipment in both Bosch and Valeo versions. The two types of units are different in physical appearance, but are totally interchangeable in both fitment and appearance.

Voltage Regulator Plug Identification

Here are the highest output alternators Mercedes makes that I was able to find. All 150A :

Engine -----Model-------Year --------Application -------- Amp kW/HP --- SysMf --Plug Conf. - Reman Alt.
4.3L-V8 --- C43 ------- 00-98 ------- Bosch 150A ---------- 150 -------- BO ---- B19 ------- AL0766X
4.3L-V8 --- CLK430 ---- 01-99 ------- Bosch 150A ---------- 150 -------- BO ---- B19 ------- AL0766X
4.3L-V8 --- E430 ------ 01-98 ------- Bosch 150A ---------- 150 -------- BO ---- B19 ------- AL0766X
5.5L-V8 --- E55 ------- 00-99 ------- Bosch 150A ---------- 150 -------- BO ---- B19 ------- AL0766X
5.5L-V8 --- CL55 ------ 02-01 ------- Bosch 150A ---------- 150 -------- BO ---- B19 ------- AL0766X
5.5L-V8 --- S55 ------- 02-01 ------- ALL 150A ------------ 150 -------- BO ---- B19 ------- AL0766X
5.0L-V8 --- SL500 ----- 01-99 ------- Bosch 150A ---------- 150 -------- BO ---- B19 ------- AL0766X

Engine -----Model-------Year ------Application-------------Amp kW/HP ----SysMf --Plug Conf. - Reman Alt.
5.0L-V8 --- CL500 ------ 01-99 ---- Bosch 150A ---------- 150 ----------- BO ---- B19 --------- AL0768X
4.3L-V8 --- S430 ------- 01-00 ---- Bosch 150A ---------- 150 ----------- BO ---- B19 --------- AL0768X
5.0L-V8 --- S500 ------- 01-00 ---- Bosch 150A ---------- 150 ----------- BO ---- B19 --------- AL0768X

Engine -----Model-------Year ------Application------------Amp kW/HP ----SysMf ---Plug Conf. - Reman Alt..
5.5L-V8 --- ML55 ------ 01-00 ----- ALL 150A ------------ 150 ---------- BO ----- B19 --------- AL0785X
4.3L-V8 --- ML430 ----- 01-99 ----- Bosch 150A ---------- 150 ---------- BO ----- B19 --------- AL0785X

Voltage Regulator Plug Identification

Cross Reference
Bosch = Mercedes
AL0766X = 0-123-520-006
AL0785X = 0-123-520-012
AL0768X = 0-123-520-017

Which one of these will fit?
What modifications might I have to do to the pulley or plug or anything else?
Are the brackets from my alternator the same size as the 150A versions?

daveCT · #2 05-22-2005, 08:58 AM

if it doesnt make noises you just need a new volt reg , 20 bucks on ebay

or get it rebuilt at a local shop , 80 bucks

lino · #3 05-22-2005, 10:38 AM

I figured since my alternator is only 70A that I maybe an upgrade would be better option. I just asked someone who has one for sale on ebay and he said that the 150A won't work on my car, because the voltage regulator hook ups and operation is different, so is the physical size.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7974975537

Does anyone know if what he said is true?

Has anyone tried or even seen one of these:
http://www.hap.com/products/Alternators/Water/index.html

lawlopez · #4 05-22-2005, 10:46 AM

First find out if the alternator is defective.

Second find out if there is a load on the alternator
when the car is stopped and closed up (that is,
when it is closed up for the night). You would need
to measure the current through the battery for this.

Third have the battery checked to see if it is ok.

I wouldn't think that replacing the alternator
is going to help you any if the battery is bad or
there is a load that shouldn't be there on the
battery.

I would think that replacing the alternator with any
working alternator would fix the problem if the alternator
is bad, and I would think that replacing it with the OEM
would be best.

I do not see that replacing the alternator with a bigger one
would help except in some bizarre circumstances. Namely
if you are using more than the current alternator would provide when driving around or if you are discharging your battery
during the night and then only driving it a short way during the day.

I must admit I've only read your original email only once and might have missed something.

Ramblin · #5 05-22-2005, 10:41 AM

I have an 83 300CD and the original 45 amp alternator was not sufficient for my needs (big stereo) and with some research found that an early Saab 9000 115 amp alternator (AL129x) fit in with some minor alteration. It is by the way the same case style as your original. I had to convert the twin B+ terminals to a single ring terminal to adapt to the new configuration. It actually was a tight fit but that was mostly because of brand new fan belts I had installed. I am not sure this is what you want to do but it seems you are looking for alternatives to the original alternator.

lino · #6 05-22-2005, 11:49 AM

Quote:

Originally Posted by Ramblin

I have an 83 300CD and the original 45 amp alternator was not sufficient for my needs (big stereo) and with some research found that an early Saab 9000 115 amp alternator (AL129x) fit in with some minor alteration. It is by the way the same case style as your original. I had to convert the twin B+ terminals to a single ring terminal to adapt to the new configuration. It actually was a tight fit but that was mostly because of brand new fan belts I had installed. I am not sure this is what you want to do but it seems you are looking for alternatives to the original alternator.

According to my book, your Saab 9000 115 amp alternator (AL129x) came on the 1988-1990 model years. Standard that car came with an 80A. The one you have is the optional version. It has the same B19 Voltage Regulator Plug Identification as the Mercedes 150A. Your car has the same B15 that I have on my 300ce. Out of curiousity, why did you choose a Saab alternator and not another Mercedes? Other than converting the twin B+ terminals to a single ring terminal to adapt to the new configuration, what else did you have to do?

Ramblin · #7 05-22-2005, 12:48 PM

You also had to change over the pulley as on the Saab it was a single belt and mine was double...The issue with using Saab instead of Benz is that most Bosch alternators of a certain vintage are the same, it is the car that is different. Many actually have the same case it is the guts and voltage regulator that are different. I actually got the idea from this forum as a successful changeover to the higher amperage unit...

lino · #8 05-22-2005, 01:08 PM

I found a great thread by GSXR / Dave M. The upgrade is possible and he is the proof!

http://www.peachparts.com/shopforum/car-audio-multimedia/53236-installed-143a-alternator-my-w124-86-95e-class-photos-post444946.html

stevebfl · #9 05-22-2005, 01:27 PM

Anything is possible, but the no brainer is to replace the 70A with a 80A, that is used on a 90- 300E. I think the number is AL66x and it should even be a few pennies cheaper.

So you say a 15% increase isn't worth foolin with, well the rating is only a part of the story. The 80A alternator is a different design and puts out about 60A at idle while the 70A one puts out about 30.

Its a straight bolt up deal and if you aren't up to changing the connector ends a new harness can be bought from MB for around $50 last I checked. The harness goes from the alt to a connector buss by the battery, simple to change. We used to change the harness but recently we aquired proper terminals and just solder up the new ends. About the same time as changing the harness. If you don't get proper ends I would go for the factory harness.