replacing the alternator--does brand matter?
 

looks like Lola needs an alternator.:furious2: Is the autozone replacement OK (lifetime warranty), or should I drop the extra cash and get a rebuilt Bosch or Denso one?:smhair:

i am sure others may disagree, but i always use bosch, have yet to have any issue, we have installed hundreds in the mercedes specialty shop where i work, i am hard pressed to remember one ever returning for warranty issues.

Are you sure you need an alternator or do you just need the easily replaceable voltage regulator that is screwed into the back of the alternator? Cost is under $40. However, I agree with Carson - if you need an alternator, I'd sure get a Bosch.

how do i test that?
 

wil the voltage test tell me if the alternator is bad, versus the voltage regulator?

I haven't bought a rebuilt in decades. The life-time warranty means you get to bring back forever. I get my starters and alternators rebuilt locally, with perfect results and a price usually cheaper than the over the counter part.

Just replace the voltage regulator and see if that fixes the problem (they're cheap). If you do need an alternator, keep the voltage regulator as a spare.

If you do end up replacing the alternator, get the correct bosch part. I once got stuck on a weekend and had a local shop put in a McParts alternator (probably NAPA), I ended up going through two of them in a month before I finally gave up and put in a bosch (after getting stuck in chicago a week later).

where is the voltage regulator?
 

none of the guys at autozone could point to it, and i still can't find a manual for this thing--not even on this site.:bigcry: very frustrating.

found it! Gonna replace and see what happens!
 

gotta get those coveralls!

It screws into the alternator and includes the burshes, it looks like this:

http://catalog.worldpac.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1CQ0J3JZ422V10EU4I&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1984&product=F4010-30110&application=000272327

I'm surprised the "guys at autozone" could find the engine.

You can replace the voltage regulator in about 10 minutes with the alternator in the car. It's at the bottom, rear of the alternator.

If you do need to replace the alternator go with a Bosch. I bought a rebuilt one off of Fleabay that lasted a year and that was it. Bought a new Bosch and it's been in there for 3 years now.

Cheers,

Bill

before you go buy just the regulator, you should remove your original one and see how worn the brushes are, if they arent very worn the regulator may not be the issue, but on the same token if they are worn look inside at the brass slip rings on the armature and make sure they arent excessivly worn or have deep groves, if they are they will prematurely wear the new brushes and you will basically consume regulators, it may be cheaper in the long run just to replace the entire unit and be done with it.

Fwiw
 

I just went through a series of charging problems on two W123 cars (84 and 85 300TD). Between the two cars I have removed or installed alternators no less than a dozen times in the last few months. I've gotten pretty effiecent at it, too.

First, my opinion is DO NOT buy an alternator from AutoZone, they are very low quality. I went through several "lifetime warranty" alternators with bad rectifiers, a bad voltage regulator and my favorite was when the case screws backed out and got caught in the pulley seizing it and melting the belts. But hey, I can jst keep pulling the thing out and taking it back. Oh what fun. If you're going to buy a rebuilt, spend the extra 50 bucks and buy a quality part.

Second, how do you know its the alternator or voltage regulator. i.e. what are the cars symptoms?

Does the battery hold a charge? A fully charged battery should read 12.3 - 12.5 volts after a night of rest.

Does the battery indicator light on the instrument cluster light up prior to starting? If not (and the bulb itself is not faulty), then the alternator is not getting a proper "priming charge" and will be unable to function as an electromagnet. My 84 had a break in the wire between the light and teh alternator. I replaced both the alternator and battery (swapped from the 85) and it still wouldn't charge. Ran a new wire and it charges fine.

Does the battery indicator light on the instrument cluster not go out when its started? Could be the alternator or voltage regulator.

Does the battery indicator light on the instrument cluster glow dimly at idle and go out when you rev the engine? Probably worn brushes, replace the voltage regulator.

If I've got something wrong here someone please correct me.

Count another vote against AutoZone alternators - I went through three in a month before getting one that worked. That one was actually the single-belt model, that I pulled the pulleys off of and replaced with the dual-belt setup off the old alt.

Sure you can take it back under warranty, but you have to ask, at what point is your time worth the difference in price?

I replaced the regulator when the battery light glowed at low rpm. Solved. On same car later the alt was screeching, as in a bearing going bad. Went to Advance Auto, they carry worldwide remans, decided against it, then the fella behind the counter suggested a indy parts store, they got me a Bosch (that's what they told me, can't tell by looking) reman. Had to swap out double pulley, wrong diameter. I am now parting out that car. Said alt is sitting in my garage.

ok, here is a correction.
a fully charged battery at rest will show 12.7 volts. (probably more like 12.65 or so) if it's less than that, the battery is not holding correct charge due to plate/electrolyte issues.
here is a nice article about car batteries.
http://www.repairfaq.org/ELE/F_Car_Battery.html
check this info out about charging voltages...
http://www.landiss.com/battery.htm
John