On a 1983 240D with 183K with an alternator not recharging the battery, what has most likely gone bad?
(1) The brushes?
(2) Regulator?
Since the car has power everything, I'm assuming its the 75 amp model, in which case, it would be worth diagnosing instead of just replacing.

You've probably already asked yourself this but: is a 17 year old alternator with that many miles on it really worth (in terms of reliability) spending money on?
Harvey

I do not have anything to contribute to the subject, but:
I find it funny that MBZ owners get upset when a part fails after 180K+ miles. :D
If this were another make of car this would be the 2nd or 3rd alternator to fail, after so many miles.

Mark.

[This message has been edited by mark300d (edited 06-14-2000).]

The brushes are in the regulator. Pull the reulator (held on with two screws on the back of the alternator) and inspect the brushes. If shorter that about 1/4 inch this is probably the problem. Often this problem will result in the Alt light going out but not sufficient amps being put out to charge battery. It is an inexpensive part and worth giving a try.

Also, on the 240 it is not unusual that a slightly loose belt will give the same problem. Because of the routing, not a great deal of belt touches the pulleys and the result is a slipping belt that will not allow battery to be charged.

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Bob1

I recently had a huge electrical problem that was corrected by simply replacing the regulator on my 240's alternator.

The regulator costs less than $40.00 and installs in minutes with a flat-head screwdriver. You can use the original bolts to replace the part, but I recommend changing them with cap-head or hex-head bolts from your local parts store. The standard, round-head mounting screws are a pain to negotiate if you do not have great tools, small hands, or patience. Also, if you are planning on keeping the car for many more years.... You may need to replace them again (after another 180K).

Good Luck,

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William
76 240D - 550K miles
78 300D - 200K+ miles

Earlier (300DT & 300SD) cars used 55A alternators & later ones used 65A. They're interchangable. 240D's used 55A ones.
Many times pre-glow relays stick & use all possible charge from alternator!!

[This message has been edited by M.B.DOC (edited 06-15-2000).]

On my 81 300D a few days ago, the prob. was loose/broken wire(s) at the plug on the back of the alternator.

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Wilton Strickland
Goldsboro, NC
91 350 SDL. 81 300D

Carrameow,

As the last post indicates, this may be your problem. Remove the connector from the alternator, and pry the plastic cover off. Use an ohmmeter to ensure that all three lugs are still tightly connected to the wires. If not, I had very good luck soldering one back on, and it still works perfect.

I remember when I was a teenager and would go crying to my Dad about something I had been troubleshooting to no avail. I would tell him that I had checked everything. His response would be, "If you haven't found the problem, you haven't checked everything", or he would say "The problem will be found at the one thing that you haven't checked yet"

My dad's a born troubleshooter, and I think back to his wisdom when I start getting stumped. That's not to say that I never get stumped, but I don't think it happens near as often now.

Good luck,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Remove the regulator from the back of the alternator (usually two screws and no wires) and inspect the two spring loaded friction contact brushes. They do wear down eventually.
I think 180,000 miles is low mileage for a MB alternator.
A replacement regulator is maybe around $75.

I just had charging problem with my '84 300D. After checking the obvious easies (belts, battery, etc.) I removed the alternator, a 55 amp unit. The bearings were ok, the diodes were good, the voltage regulator was bad. I priced a replacement voltage reg. at the local german shop, $79. At NAPA $41. I called Autozone & they did not sell a regulator, but did sell a remanufactured 55amp alternator, $95 with a lifetime warranty. As I intend to keep the car a while, I opted to spend a couple extra bucks and installed the lifetime warranty reman. So far, so good!

Just a note here of my experience with starters and alternators on these cars.

I've been through many of both, and my experience has been that you're money ahead in the long run to get Bosch certified rebuilt starters and alternators for these cars.

One Mercedes owners experiences does not make enough data to draw meaningful statistics, but that's been my experience.

Hope this helps someone,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles