Alternator for ' 86 300 E

[Sabik]

Would anybody know if there is any difference between a 70A or a 80A alternator, besides the difference in power? Would it be a problem if i got the 80A even if i needed the 70, or vice versa. Any difference in the connectors or anything like that. From what i know, i need the 80, cuz i ahve power windows and sun-roof. Atleast, thats wat some people have told me. One more question, any idea how much a used one should cost?

[flyonwall9]

Why not take the one you have and have it rebuilt. Sure is less money than new and if its your old part you already know what kind of shape its in. Also, depending on the problem with it it may only cost a few dollars to fix. I know mine needed new brushes, 12 dollars and I was back driving and only tool I needed was a screwdriver. Didn't even have to take it off the car.

Sabik - your car uses the 70 amp alternator. Later years used the the 80 amp unit (I believe >1990). The wiring harness is different for the two alternators, so they aren't readily interchangeable. As with anything, you could make the 80 amp alternator work, but just keep in mind that you even though you get more maximum current out of the 80 amp unit, your current-at-idle will suffer somewhat (could be a problem idling with stereo, lights and ac on). So you will be getting more power, but it will be at a higher engine-speed.

The other important consideration is what flyonwall9 brought up -- Are you sure your unit needs to be replaced? My alternator wasn't charging, so I brought my car to a shop and they quoted my $150 for a rebuild. I decided I would try my luck with a set of new brushes even though mine didn't look old, and three years later it's still working.
Best $12 I ever spent on my car.

Peter
1988 420sel
1988 300e
2001 X5
1999 S70 AWD
1997 960 Wagon
1996 850
Arriving soon: 2002 530i

[csnow]

Try this place:

$76.95 Net cost with 3 Year warranty.
You can even get $15 back for the core, if you feel like shipping it back.

Was cheaper than most of the used units I priced.

They come nice and clean. Mine has been going strong for years.

http://autoexpress.safeshopper.com/532/2320.htm?136

[Mike Murrell]

To add to Peter's remarks.....

Pull and examine your brushes first. New ones are about 1/2 inch in length.
If yours are significantly less, a new set could give you added boost.

How to do it:

- Elevate front of car. Ramps are nice.
- Brushes in your case come off the bottom of the alternator. Two(2) phillips screws hold them in. Remove and exmaine. If worn, buy new ones and plop them back in.

It takes longer to setup for this job than it does to remove and replace the brushes. Very easy task.

[stevebfl]

As to the original question, I would never replace the 70 amp alternator with a 70 amp alternator. They are POS. The difference between the 70 and the 80 amp is that the 70 puts out about 20 amps at idle whereas the 80 puts out about 60 amps at idle. The difference is more like as if you replaced the 70 with a 210 as the most important time has the 80amp tripling the current output.

This matters because the original alternator is the continuous source of battery problems in cars that use the AC and idle a lot. At idle with the AC and fans on the 70amp alternator is about 20 amps in the hole.

The other miracle is that the 80 amp costs me less than the 70 (only a couple bucks...BUT!). One will have to replace the harness MB # 124 543 45 26. It costs $57 list from MB and is simple to replace as it just goes from the alternator to the connector close to the battery.

WE now convert the old harness but this should only be done with suitable connectors soldered in place. A couple yellow crimp-on connectors IS NOT SUITABLE.

[fish4stripers]

Never realized brushes were so easy to replace.

If I ever attempted this, where can you buy them? Go to a starter/alternator place and just buy parts off of them?

Any place online?

Thanks,Jeff

[Mike Murrell]

mercedesshop parts site probably sells them. you can also buy them locally from european parts suppliers. check local yellow pages

[Sabik]

Seems like the only problem I had was with my voltage regulator. The brushes were worn out pretty bad, and since the one I had came as one single component I couldn't just replace the brushes, so I had to order another one. Cost me $20 from AutoZone. Like you guys said, it's less than an hours work and you save a pot load of money if you do it yourself. Good Year had given me an estimate of $337, and all it cost me in total is 30 bucks including the shipping. Just need to find the right screwdriver and rachet and you should be all set. Again, thanks for your advise guys.

[Zeus]

I'd echo Steve's comments about upgrading to the 80A. His advice paid off for me.

My 70A stock alternator finally failed after many regulator replacements and years of service and I decided to get the newer 80A unit. BIG difference. The one thing I noticed right off the bat was no more flickering dash lights at idle. I could even turn the AC on at idle and the lights wouldn't dim - something that always happened before.

It's a simple conversion. The alternator itself bolts right into place, same belt, etc. Rather than buy the upgraded wiring harness, I just soldered on some connections myself (the 80A Bosch unit I bought had bolt-on connections).

Simple job, big pay-off.

[brewtoo]

Who is that made those alternators, Bosch?

They should be commended for making it so supremely easy and economical to replace the brushes/regulator! Probably the easiest job on the whole car, except maybe putting air in the tires.

[Impala]

I used to have a 89 260E, now a 95 E320. According to the owner's manual

89: 260E, 300E/300CE all have 70A alternator
95: E320 has 90A, and E420 has 110A

Is the 80A alternator for another model year? Will the 90A or even 110A alternators just as easy to retrofit for the older 70A one?