Alternator - More Info

[ChrisInNashville]

OK, I go into AutoZone with my Haynes manual and say that 'I'm stupid' and 'I want to buy all the tools dicussed here'.   They say 'we'll do that for you' - Yeah!   So I go get the car and here are the results from there computer:

Battery output 11.7 to 12.5 volts and 9.5 amps.   The diagnosis:  a bad diode in the alternator.

So here are the questions:
1) Given that I'm a newby, can I take on the alternator change or should I get Hans, my trustworthy mechanic, to do this?
2) AutoZone can sell me a reman alternator for about $95.   Should I go with that?   Should I buy new (is that an option)?  

As always, I really value your insight.

[Cees Klumper]

New is expensive (something like Euro 450 here) so the remanufactured price sounds very good to me. I would go with that if your alternator is currently not functioning right. Just make sure they give you the same thing you are trading in.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello,
Removal of the alternator is fairly easy, depending on our model W113 and your mechanical experience. Some basic tools are required.

If you have a W113 with AC the alternator is right on top and may take only ten minutes to remove. Otherwise plan on spending a little more time and some of it under the car.

Don't forget to disconnect the battery first. There are only two attachments holding the alternator on. The long horizontal bolt at the bottom bracket connection and the short horizontal bolt attaching the adjuster rod to the alternator.

These cars have external voltage regulators which can go bad also.

You can have your alternator checked when it is off or have it checked by someone while still in the car. If there is a problem with the regulator it can be diagnosed also.

We can get into this testing, but unless you at least have a voltmeter and ampmeter you will not be able to do it yourself.

As long as the remanufactured alternator is the correct original Bosch it may be worth a try from Autozone. Rebuilding alternators is not rocket science. The price is right and it is not that difficult to change out. What kind of warranty? let us know how it works out.

You can also find a rebuilder in your area to rebuild your original unit.

 



Joe Alexander
Blacklick, Ohio

[Shvegel]

Also there is a junction block under the alternator that can get corroded(at least there is one one my 1970 280).
  Even if your car is not restoration material I would strongly suggest finding a rebuilder in your hometown or nearby. These are fairly common units but when you lose the original it is gone forever.

[Bob G ✝︎]

Do you have a 35 watt or 55 watt alternator. Is the your regulator build into the alternator or on the right hand side of the fender well inside the engine bay. I ask this because you need to know what to buy and ask for. If the alternator is on the top with Air Conditioning it is fairly easy to remove. You will have to turn down the ajustment nut on the top that looks like a long threaded rod to give some slack to the belt and then remove the two nuts one on top side of the alternator and one on the bottom to remove the unite.
Once you have accomplished this bring it to an auto parts store that deals in Bosch rebuilt unites. All ways check what kind of plug you have on the back of the alternator to remine you to get the right one.
Early alternators were 35 watt and can be up graded to 55 watt with or with out a build in regualtor. You may have to get a different plug if you do this up grade other wise just replace or have rebuilt what you have.
Cost should be about $125.00 at most. Remember to replace your alternator built while you have the unite off.


Bob Geco

Bob Geco

[graphic66]

I have a 66 230SL with AC and the alternator is below the AC unit. It is a real knucklebuster to remove and/or adjust the belt. I have not seen the reverse with the ac compressor below the AC. If your alternator is below, start by removing the horn, and from there it's pretty much basic mechanics. While your in there get some new belts and check you tranny cooling lines if you have an automatic tranny. My car must have had some alternator work attempted as it was missing that horn and the alternator wasn't charging good. Oh well one more trip out to the parts car and all was well.

[ChrisInNashville]

My trusty mechanic, Hans, says that I can replace the alternator myself, but clarified that the AutoZone reman is not a bosche, so he'll get me what I need.   More to follow soon...wish me luck