Alternator Problems, what should I do?

[deerefanatic]

Hi all,

In december when my Alt went out I took it to a local alternator/starter repair shop and they put a new (aftermarket, not Bosch brand) voltage regulator on it. all is fine.......... New battery about 3 months ago......... Fast forward. Battery light comes on all at once on me. I order a new BOSCH brand voltage regulator from Rusty at *************** because my charging voltage is only about 12 volts............ New regulator on............ Still only developing 12.5 volts maximum traveling down the road. funny thing is, I can draw like 35 amps off of this 55 amp alt at 2400 rpm engine speed and it still runs along at 12.5 volts!

I'd like to upgrade alt size, so I definately want a 65 amp minimum! JC Whitney has remanned Delco gm alternators in 100 amp size for $110 (no core, nada. Bottom dollar price.) These are new remans. ($125 will get it in chrome! ) A new bosch remanned alt in 65 amp size is at least $150. So I am heavily leaning toward going with a gm alt and just making my own bracket.........

My question is, If I get a new 2-wire GM alternator and hook it up, will the charge light on my dash still work? That's the only concern I have.......... my metal-working skills are good enough that I'm not afraid to make my own alt bracket...........

Advice anyone? I'd love to stick with bosch, but unless I can get a 100 amp Bosch for less than $175, I can't justify it..........

[Jeremy5848]

Originally Posted by deerefanatic

My question is, If I get a new 2-wire GM alternator and hook it up, will the charge light on my dash still work?

The electrical diagram for my 1985 300D (W123) car showswhat I think you mean by a "2-wire" alternator. (Might be different for your car.) One wire is the wire from the idiot light and the other goes to the battery. Plus ground, of course. I assume the GM alternator has the regulator built in? It is probably similar to the alternator in my 1989 Oldsmobile. It should have the same two wires. As long as the trickle current through the idiot light is similar (I forget the correct technical term), it should work. If it doesm you can go into business making adapter brackets so we can all do the same thing!

[Hit Man X]

Al129X Bosch is what you want. It's 115A I believe.

[1985 300SD Sady]

Originally Posted by Hit Man X

Al129X Bosch is what you want. It's 115A I believe.

Yes, hes right. Bolts right in, but you will need to upgrade the wiring to handle all those excess amps.

Try car-part.com

Most of those junkyards ship, what you want will probably come out of a 1993 Saab 900. I got mine for $50 shipped. Search my name for my thread.

Also read the upgrade alternator master thread. Its called something like "Alternator - Bosch Al129X in a w123, and it works!"

[Hit Man X]

I'd have done that, but I just got a like new 80A for $10. Bosch reman. I'll get to it.