Can one extend an alternator's life by merely changing out the Voltage regulator/brush pack? I have 215K on mine and I am driving X-country next month with my 87 300D and its the only component I am nervous about. I realize that many times the brushes go on alternators while they are still good. On the Mazda RX7's you could put new brushes in easily. The Volt Regulators also dont last. The last items, the stator and rotor(& bearings), are the Big Items. But they are just windings and magnets and not particularly fragile--if they remain stable for 500K, all you would have to do is change out the Volt Reg and Brushes and you would be fine.
Of course it isnt that EZ. Sometimes when you change out the VR Brush Pack, your Alternator is still dead..

Anyone got any input?

I have replaced the voltage regulator twice; both times it gave the alternator an extra 2 years of life. I can get them for $20 locally, and they are simple to change.
If you pull out your old one and the brushes are worn down, you can bet it needs replacement. I suppose there are other things which can go wrong with them....

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Think Alternative Energy!
300CD '80 (now gone but not forgotten...)

If I were driving across the country with a 17 year old alt, I would have it rebuilt. I wouldn't care if it stopped charging, with a diesel you can work around that. I would worry about the bearings going bad in the middle of no where and then you are stuck. Thats the only problem with a serp belt setup one thing seizes and you are in trouble.

I would also replace the water pump if it is original and keep the old one for a spare.

Also find a serp belt that is shorter so you can bypass something if you have to.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Everything else is new, the water pump, etc. --If the PS Pump goes, it usually shows leakage first; i.e , doesnt fail catastrophically and I can change that out on the road--I always carry an extra sepentine

The reason I am saying this is because the bearings on my alt went bad fairly fast last month. One day they started to make noise and got worse very fast from their. Within 300 miles.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

When I bought my 300CD last July, the main negotation point was that there were no volts coming from the alternator. I got the price down by a GRAND, knowing that I could replace the regulator / brush pack for about $20.

Smart boy got fooled. Replaced the pack, no volts. Whimpered for a few minutes, then took the car to Orem Auto Electric. They pulled it, rebuilt it (stator winding was open), remounted it. I was watching the meter when they started it up. 15 ... 14 ... 13 ... 12 ... 10 ... 8. I hollered at 10.

They whimpered for a few minutes, then pulled it again, and built it again (regulator left town). Owner of the place started growling, and tech went and applied the charger to the battery. After reinstall, they asked me to leave it overnight, so as to charge the battery all the way.

It works now. Charge the battery before you change the regulator.

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Alan the Radio Guy
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Amateur Radio Station N7CEU
1985 300CD 199,000 and still rolling

That might be a costly move. The last water pump that I bought was $35, with a $75 core charge. That's a pretty expensive spare.

I just bought one for $85, I'd rather have one sitting in the trunk then trying to get my hands on one in the middle of no where. How good can a 17 year old pump be?

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

[QUOTE
Of course it isnt that EZ. Sometimes when you change out the VR Brush Pack, your Alternator is still dead..
QUOTE]


I started having radio problems (powering on and off) while the defroster was blasting, lights were on, wipers going and rear defrost on. I suspected
brushes (I refused to believe it was the alternator). Dranied the battery once and needed a jump. Changed the brushes and noted the ones I took out (after I snapped one of those POS little slotted screws ) didn't look uneven or too worn. Verdict; no charge-a de batery, with new brushes. So I say nope, if she's gonna die new VR won't breathe any extended life into it. Although I hoped it would


Pete M

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1999 E300DT (131,800) 154,000 Black on Black SOLD

2006 CLK 500 coupe Capri Blue on Grey (zoom,zoom)
47,000mi

04 VW TDI Passat 80,000mi
(Techno)

How to eliminate oil dependency through market-driven approaches.
“We could cut oil use in half by 2025, and by 2040, oil use could be zero,”
The Sound of Diesel Speed
Ode to MB

I finished putting on my new alternator on my 300sd today. Mine is a 1982 with 255k miles. The original alternator was rebuilt 7 mos. ago at a shop out of town when I got stranded. It just stranded me again. Guess what it was? Bad brush pack which is also your voltage regulator.

I was told conclusively that any other brush pack than BOSCH will not last. New brush pack at Mercedes dealer is $65. It sells for about $45 elsewhere. Just make sure it is BOSCH.

I replaced my alternator with a remanufactured BOSCH. Total cost $160 and it is warrantied for one year and comes with free roadside assistance for a year if it fails or battery dies. Good anywhere in the country.

The new alternator for my car at the dealer was $600. It came from Germany. Well guess what? On the box of the factory rebuild Bosch I paid $160 for? It was rebuilt in Germany too.

Now I have a spare alternator if I don't turn in the core for the $75 charge.

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1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

You'll get to a stage when the slip rings in the alternater hget to badly worn they'll eat brushes and youll need to replace them. Also its a good idea to replace the bearings, they're cheap anyway.

When car batteries get really flat they pull ALOT of current when you start to charge them, thats what probably blew your regulator.

German KAE regulator has extra long brushes, $27.00 delivered to the door.


P.M.

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1999 E300DT (131,800) 154,000 Black on Black SOLD

2006 CLK 500 coupe Capri Blue on Grey (zoom,zoom)
47,000mi

04 VW TDI Passat 80,000mi
(Techno)

How to eliminate oil dependency through market-driven approaches.
“We could cut oil use in half by 2025, and by 2040, oil use could be zero,”
The Sound of Diesel Speed
Ode to MB

I agree with this. Bosch seems to be good about wearing the slip rings down. I would say you could get about one replacement of the brushes before you need to replace the slip rings and bearings.

well, someone here needs to say If it ain't broke, don't fix it! That being said, if you are really concerned about it, removing the brush pack and inspecting it prior to a very long trip makes sense. From this you can get a lot of free information about the condition of the brushes and the rotor contacts. You can loosen your belt and check for noise and play. You reduce the risk of breaking something unintentionally. If you find the brushes are pretty worn but the rotor looks OK, put the new brush set in. If the bearings are really falling apart, you'll find it. Bring a set of basic tools with you anyway. Chances are, if something fails along the way, it will be something you didn't think of.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Once on a business trip, I had to drive from NJ to Tennessee, I figured I could use the "mileage" reimbursement to buy some stuff when I got back.I was so nervous, i actually brought a Floor Jack, jackstands, all my metrics, a DVM and some spare parts...it brings back laughs, because I was at the hotel and bored one night, because the town was so small, and all my workmates were at the Stripper bar, so I went down to the Parking lot and jacked my car up and did some work on it..I also remember thinking facetiously, geez maybe i should even bring a spare engine...