HEy, here is yet another alternator post. I tried searching the forum and found nothing on this yet so I thought I'd post.

I went out to the junkyard to find one of the AL129X alternators from a SAAB. I found a Saab with an alternator and started ripping it out. However, it had no markings and looked old. I grabbed it anyway, after fighting the saab for it. (I EARNED that alternator) Kept going, but with no luck. I found another Saab but the alternator had already been robbed. Disappointed, I kept going. No Mercedeses to be found at all that day, I was feeling very sad. No more Saabs either.

Well, I was about to give up hope when I came across a 1987 BMW 535. I looked and there was a nice Bosch alternator with a V-belt. Looked about the same as the unmarked saab in my hand. I ripped it out, and it was rated 90A. I took it home with me instead of the saab alternator. For seventeen bucks I can afford this little experiment.

This looks like it will fit. A quick search gave me the part #AL49X. May be a good alternative, I will report back later this week when I install it. Looks very much like the stock alternator, but has more air holes on the back like the AL129X. If this works, it may be a good one for people who can't get their hands on that elusive saab alternator.

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'79 240D 4 speed manual 105k miles

Awesome! I am going to keep my eyes open for one of those (either the saab or a bmw) when I go to the u-pick next....


Does it have the same type of plug connector on it? Or does it need modification to the post/nut style?

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

i pulled one of thoes first for my 116. it will fit i believe.

pawosd- i think they are the post kind. not a hard switch over.

i was trying to make a write up on the 116 with pics but i can't get the pics off the camera right now.

__________________
-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto

Yes, the alternator has the post connectors, but I am not sure that's a bad thing at all. If some heavier cable is installed, that will help by having less voltage drop, and energy used up via heat because of the resistance. With 90A available, you may need the heavier cable. I intend to redo all the wiring from battery, to starter, to alternator. May help some of my cold weather starting, if the cranking speed is better.

Anyway: the alternator has two main connections. Both are screw (post) terminals. The big one, or the B+ connection is the main power out. This needs to go to the starter (and therefore to the battery). The other one is a smaller connection labeled D+ that goes to the smaller existing wire (blue, I believe) for the dash light. It may also energize the field coils, I'm not sure if that is internal or through this wire. The case of the alternator is the ground, so make sure it has good clean connection to the bracket.

I do hope this works on W123, this alternator did not seem to be rare. I believe it may be on some VW's also. The older BMW's that had it (I saw a few) even have the correct V-belt pulley already on them like the one I have.

I saw a couple of BMW's that had a very similar looking alternator, but with an air duct inlet in the top of them that came from the front of the car. Cooling, I suppose. May have been higher amp alternators, that may bolt up well. I didn't get one for fear of the duct causing mounting issues. For a brave soul, it might be worth looking into.

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'79 240D 4 speed manual 105k miles

i installed some massive cables on mine. i went from B+ to the terminal block under my battery.

the D+ i put a small wire on that will plug into the blue dash wire. all works well.

wth the 115A alt i have 14.4V at the battery at idle.

__________________
-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto

Wow! 14.4v at idle! I get about 14 with headlights/radio on. About 13.5 with the blower on also, which isn't bad. And as soon as I bring the engine over 1000rpm I get full 14.4 with most things turned on. I'm going to look into that upgrade someday....however, I put on a brand new 65A back in July....and I intend to get my money's worth out of it first. It seems to handle everything ok, a little low at idle, but quite a bit better than my worn out 55A that I had before....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

yeah.. there were a few tmes after i finished installing the engine that i would get in after driving at night for like 40 mins. go to fire it up and everything is dead. get out check the battery cable the positive is not touching the terminal at all, re connect it and it fires right up.

i can drive with no battery at night with this alt, and have everything run that i want to like the stereo, fan and lights.

it is definaely an upgrade i reccomend

__________________
-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto