the 300sd has had a charging problem for sum time. ive never really had the time to look for it until this weekend. turns out the brushes were worn out. i cleaned the unit up, lubed the bearings and installed a new voltage regulator assy.

picture shows new and used. notice the difference in the brush sizes

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have no worries.....President Obama swears "If you like your gun, you can keep it

funny you should mention this.

After a hot spell over 100*F, I couldn't start my car one day, thought it was the battery.

After some diagnostics, I found it was the VR.

Now, the one I took out had an adjustment screw on the inside, while the replacement did not. The old one had full length brushes on it... seemed early to fail.

Does anyone know if the adjustment could revive the voltage regulator's function?

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Yes, the MB alternators must be made of kryptonite. At about 250,000 miles, give or take I had to replace the VR due to worn brushes. The amazing thing was that the rest of the alternator was still and is still in good shape with the car now at 320,000 miles. Amazing.

9 times out of 10, when the alternator light comes on for most any car it means that the brushes are worn out.

that's just the thing, my light didn't come on.... and I know its works b/c I've left it unplugged before.

This leads me to believe it was charging... but insufficiently... hence the adjustment.

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You're probably correct. It was charging enough to keep the light off.

yea everything else still looked good. resealed the p/s pump, and most of the engine too. i am now officially leak free

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have no worries.....President Obama swears "If you like your gun, you can keep it

I have a problem where my battery keeps going dead...the auto parts store tested it and found that it's putting out 900 CCA. When we tested the system with my car running, it showed that my alternator was putting out low....I just put this thing in less than 6 months ago.

When I drive at night, my alternator light shines very very dim, but only if the headlights are on. With the headlights off, no alternator light.

I've cleaned the battery posts and reconnected the cables, I also re-did the Negative connection to the body.

I'm next going to try tightening the belt, as it looks to be a bit loose, but it's been working fine until just the last month.

Any ideas outside of this?

Thanks!

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1998 W202 C230 - The money pit of late.
1984 W126 300SD (356,800 miles) Gone to the wrenchapart
1984 W123 300D Gone to the wrenchapart
1972 W108 280SE 3.5 (sold but not forgotten)
1986 Buick Grand National 3.8l Turbo (86k miles)
1966 Glassic Model 'A' Replica http://www.glassicannex.org

http://banners.wunderground.com/weat...Round_Rock.gif

it could be worn brushes. what was the output at idle with the lights on? also check the pigtail on the back of the alt. i had problems with that recently too. if you can give us an output reading at idle as well as a reading with the engine revved it would help. have you tried metering it yet?

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have no worries.....President Obama swears "If you like your gun, you can keep it

Depending on what replacement the alt is, it wouldn't surprise me you need a new VR, they're relatively cheap and easy to inspect/change out.
The belt should have a half inch to one inch of travel in the middle between two pulleys, too tight can cause a premature bearing failure, much more expensive to correct than just keeping properly tightened belts.

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83 SD

84 CD

Anyone know of a place to get a VR quickly? Like where I don't have to wait for shipping? Thanks.

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Current cars:
2000 ML55 AMG, 174k miles
2003 C240 T-Modell, 202k miles
1995 S320, 207k Miles

bap carries the bosch. but you pay about 20 dollars more.

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have no worries.....President Obama swears "If you like your gun, you can keep it