Voltage Regulator again??? 1987 300TD

[jonbobshinigin]

In four years this is the forth regulator. The one in the car when I got it went bad, replaced with KAE before I knew any better. One year later I'm dpi gig again but this time with a genuine Bosch unit. Had the original alternator rebuilt six months ago (local trusted guy who also added some diodes) which at the time I put a new Bosch unit in. Now my battery light comes on yesterday and I just stopped by auto parts store and they tell me battery is fine and the regulator is bad!

I removed it and the brushed seem fine, and are adequate in length. However, the part that the brushes contact (rotor?) seemed like a pretty good channel has been worn into it.

Why does my car keep eating Voltage Regs?

[compress ignite]

The Two Separate "Copper Looking" rings on the Shaft of the Alternator,
That the Brushes "Ride" on making contact.(Slip Rings are all one Part)

If they are worn Too much (You can catch a Fingernail in Them, USUALLY
means REPLACE.)
That's what's Chewing up your Brushes.

Thing is they have to be Soldered in with "95/5" silver solder and then
"Trued Up" on a Lathe.

If everything ELSE is G.T.G. (GOOD TO GO) an Alternator Shop should be
able to install and True your new Slip Rings.

Get the BOSCH part Number off your Alternator (It's on the Black Plastic Back Cover)

And call these guys about a new set of S.R. s

http://www.wagneralt.com/

(909)465-1950

[jonbobshinigin]

Thanks so much. Yeh, I can visually feel the lip...but my brushes really don't look that worn so I'm kind of confused! Might the regulator have failed me? As I idle, the light is dim, while accelerating, it becomes brighter.

[compress ignite]

Check the Grounds (Engine to Chassis) ,Etc.

Heck, check ALL your charging system wiring for continuity.

Somebody [?]Ran a BIG cable
(As big as the Positive Feed Cable from the Alternator)
from the Battery Negative to the Alternator Support/Holder and fixed ALL his Problems.
These Alts are grounded through the Alt Support THROUGH the Block.

Mercedes Didn't spend a Nickle Extra on Larger Amperage Wire than they HAD TO; 20 + Years Ago.

I Believe Something MAY be wrong with your Rectifier/Diode pack.

A quick trip by Advance with a hookup of their Charging system tester WHILE
the Car is running will tell a lot.

[compress ignite]

Fall back on my Original pick up of your Slip Rings...
If the Grooves (They're not Grooves but Rectangular Channels) Worn in the
Slip Rings are OFFSET at all from the Brushes you MAY not get Good "Contact".

Something sure seems to be "Killing" regulators.

Dim "Battery" bulb @ Idle that Brightens With R.P.M.s
(I can't remember what that's indicative of (Besides my old age),BUT it's a specific symptom)

[jonbobshinigin]

As I said, the auto store hooked up to it running and it showed the regulator to be the issue. When I had the alt rebuilt, he setup an additional place for me to ground to the vehicle, which I did. The bulb is the same as the last 5 years and this rebuild has been fine for 6 months till now.

[Air&Road]

I've had great success with voltage regulator replacement with the grooves in the slip rings being as much as 1/8" deep. That said, your local alternator shop can easily replace them and turn to size on a lathe. It's everyday work for those guys.

Hope this helps,
Larry

[jonbobshinigin]

The guy who rebuilt it is convinced that it is a trio/rectifier or something like that. He is gonna check it out for me. It is still charging with no I'll effects thusfar. I've not put a meter on it, I'll try that today.

[jonbobshinigin]

Voltimeter shows 12.9 while idling. I have a trip 1.5 hours away I'm leaving for on Sun night...and my alternator guy says I wont make it. However, I have been running my car for two days like this for over 100 miles with AC and lights at night. He can't get to it until I ge back on Tues or Wed.

Am I going to damage anything? Can I make this trip at night?

[sixto]

Do you have any high current draw accessories? Dual SPAL fans? 5000 watt stereo? Aircraft landing lights? Hydrogen generator?

Sixto
87 300D

[vstech]

if the battery is fully charged, and the power output is 12.9, you should be able to make a trip like that. I'd take an additional battery with me if I had to go, but I've got 20 some cars... wall mart has 1200amp jump boxes that could extend your trip or get you out of a jamb if you had to shut off the car...

[jonbobshinigin]

I have no doubts that I can make the trip, my issue is being sure I'm not damaging anything by driving it in this condition.

[Air&Road]

I'm a little suspect if it's only reading 12.9 Volts across the battery when idling. I would expect to see 13.4 or so. You need to rev it up a little and see if you get more than 12.9. If you don't, the alternator is probably not charging. Not a good situation when faced with a significantly long drive ahead of you.

Larry

[jonbobshinigin]

Okay... I have it set up in the cabin. Cruising at 40-50 mph with AC off = 13.25v steady.
Once I turned AC on, it slowly went down to 13.10 or so. Then in the mid 12s once I stopped at a light.

[John Carroll]

Last week had my alternator rebuilt by an old line Indy shop. Returned same as 12.9 V was max at 2000RPM and idiot light came on at idle (12.3V). Shop said that the regulator was defective from stock and tried another with same result. They tried installing 'my' new regulator in another known good alternator putting out 13,8V and voltage was reduced to 12.9V. Simple fact: there is a defective batch of regulators from stock 'out there'. Shop called supplier and they are in process of replacing the inventory this coming week. Have to presume these defective regulators are outsourced to defective Mfg.in defective Chinese sweat shops.