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Discussion Starter #1
My 1989 2.6 190E began to get dimmer last night on the highway. I pulled it into a gas station and put a voltmeter on the battery, it was reading 9.0volts. I left it to idle for about 5 minutes, during which time the voltage continued to drop to 8.5, and the car died. I suspect the alternator. However, when I pulled the voltage regulator off, I noticed that the brushes were worn down to about 1/4inch. And, one of them was black on the top, the other was chrome colred, like it's been making contact, the black topped one proabaly wasn't making contact with anything.

How do I know if I need the alternator or the voltage regulator?

Sean
 

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1989 190e 2.0l
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I've just bought a 190e myself and am new here but you've just answered your own question.
If one of the brushes isn't shiny on the end then it isn't contacting and thus can't work.
By coincidence i pulled mine out this morning to check on it and mine must be a tiny part of a mm from failure too.
a photo of it is at this url
http://members.iinet.net.au/~farmerjim/log/log.html
 

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'96 sl500, 87 300td
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You should be able to purchase brushes from the dealer and install yourself. Have done that on a 123 and 115 diesels.
 

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Discussion Starter #4
My voltage regulator looks like the one posted on the URL, but one of the tops was completely black. I'll assume I need a voltage regulator. But, I guess I'm still a little unclear about things.

How do you know when the alternator is bad?

Thanks
Sean
 

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1989 190e 2.0l
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I replaced the brushes today in my regulator. They only cost AU$5.25 and even came with new springs. How much did the whole regulator cost?
I must confess i had a bad bugger of a time desoldering the old brushes because they were crimped good and tight as well. I now have a nicely burnt thumb from the soldering iron slipping.
Do yourself a favour and replace the brushes in your old regulator sometime, then keep it as a spare.
I seriously doubt if it has any other problem.
 
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