Some of you will recall that I was stranded in Toledo around Christmas time. Turned out that it was a voltage regulator (brushes shot & system not charging).

Today (45 days later), I developed the same symptoms as the battery light came on. Upon checking with a voltmeter, I noticed 12.8 with car off and 12.5 with it running!

I sprayed the contact points on the alternator to no avail. Next I took out the voltage regulator even though it was new. One of the brushes was barely showing while the other was long and new. I figured it got stuck in there but upon examination, it had worn down already.

I looked up into the alternator and noticed that the rearward track (that the brush rubs on) was not smooth like the forward one. It had a rut in it running longwards.

QUESTION: Am I right in assuming that the alternator needs rebuilding because of it chewing up the VR brush? Or can I just try the easy road again hoping to find a better alignment.

DISTURBING: Both instances seemed to have happend after a prolonged period at idle (30 minutes or so). That bothers me because one of the perks of a diesel is letting it run.....

Help??

Don

__________________
DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

Don,

When one brush wears faster than the other, it is time to rebuild the machine. That you can feel the rotor damage is a clear indication that there is a mechanical problem that is eating your brushes, and damaging the rotor. The mechanical problem can arise from internal unbalance in the electrical configuration of the machine (diode failure) and one of the brushes gets hot enough to make a dimple in the copper conductor on the rotor when the car stops. Of course, bearing wear or foriegn material in the area can cause the same problems. Once it happens, you have to turn the surface, and correct the original problem.

I would be inclined to get one of the rebuilt, 65 amp models from FastLane. They cost about the same a local rebuild around here, and you are more likely to get something that has had the diode ring and the rest of the electrical features checked out. The work for you to change them is the same, so it will turn out to be a decision based on cost and timeliness. Good Luck, and I hope this helps. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim:

Thanks for the confirmation. Any special instructions on taking out the alt? Couple of the bolts look like a tight fit up in there. I just finished the starter last week and was hoping for a month off from crisis maintainence to tackle some of the more exciting upgrades. Oh well...

Thanks again,

Don

__________________
DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

Don,

I believe you have the arrangement with the alternator attached to a special bolt that goes through the support bracket. You tighten the belt by turning a nut like feature on the bracket that the bolt is threaded into.

There was a recent thread on this subject from someone who still had grease under their fingernails from doing the job. If you can find that, you will be better served than by my recollection. But here it is anyway.

The mount is arranged so the alternator rotates about one of the fasteners, and the other one slides in a slot to lock the assembly when you have adjusted the tension on the belt. I believe the sliding one is connected to the adjusting bolt. There may be another bolt somewhere, but I don't think so. It would also have to be able to slide and I do not recall two such devices.

You have to loosen both of these sets of fasteners (bolts with washers and nuts, all 17mm or 19mm, I believe) to adjust the belt tightening feature all the way in the loosening direction. Take the belt off at this point, and remove the two fasteners. Unplug the wires going to the alternator, and I believe the alternator is yours to take away. It is not that easy as I recall, just because nothing ever is. I remember the adjusting bolt being pretty tightly captured and deforming my bracket somewhat by getting things out of sequence. Once it is free of the adjusting nut though, you can just spring it out of the recess it sits in (the hole in the bracket that is not threaded will catch the end of the bolt so it won't slide out from its position of being aligned with that hole. It has to be able to come forward to get that locking bolt arrangement out. You will see what I am talking about when you get going). It is a half hour job, even with some special man made challenges to get the old one out, and about the same to get the new one in.

I recall a spacer piece, like a section of tube that goes over one of the bolts. It can get glued in place by dirt and grime, and then come out when you are jerking the alternator around to get it out, and not looking for parts to fall off the bottom. Not a good feeling when you go to put things back and realize a part is missing and you know you do not know where it is. I found it behind a tire, where it rolled.

Installation, believe it or not is easier than taking one out. Partly because by now you really know how the parts go together, and because you understand the sequence of how to get them to fit. All stuff you tend forget after a few years......

Hope that helps, and good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim:

Thanks for the extended directions because most of these jobs are my first and I need all the pointers I can get.
Be sure that your words will be printed to paper, soiled and oiled and added to my growing book. I value that book many more times than the manual which grows dusty from neglect.

TXBill:

Thanks for the words as well. I'm glad that beast isn't as heavy as the starter.

Don

__________________
DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

It has been my experience that when a regulator or brushes go out, it does not alert you with the "idiot light". Wish it did!

I believe the light pops on if the one of the diodes goes out.
I have replaced this diode ring and made the alt work again.
I find these alternators easy to disassemble and combine parts to gain a useful example.

But, if your alt is a major PITA to get in and out-get a good rebuild.
If price is an issue, you might have some good luck at a yard finding a recent genuine Bosch rebuild.

__________________
Ed
1981 300CD (Benzina)
1968 250 S (Gina) 266,000 miles!
1983 Alfa Romeo GTV6 (Guido)
1976 Jaguar XJS-saved a V-12 from the chevy curse, what a great engine!
1988 Cadillac Eldorado (better car than you might think!)
1988 Yamaha Venture (better than a Wing!)
1977 Suzuki GS750B
1976 Yamaha XS 650 (sold)
1991 Suzuki GSX1100G (Shafty Gixser)
1981 Yamaha VX920RH (Euro "Virago")
Solex Moped
1975 Dodge P/U camper


"Time spent in the company of a cat, a beer, and this forum, is not time wasted!"

240 ED,

I have read that the brushes fail without making the dash light come on. My experience has been that driving a night the red warning light starts to glow a deep red, not the bright red it shows when you put the key in the "ignition" slot and turn it to the glow position. If I turn the lights off the glow dies and when I turn them back on it comes back. Of course when I shut the car off it is too late, and the battery is unlikely to start the car in the cold.

Don,

On my car the alternator is just below a vapor separator can that is mounted to the intake manifold. This thing gets its vapor from the engine valve cover blow-by vent, and has a drain line to dribble any liquid oil in the vapor back to the oil pan and another connection to feed the vapors to the intake manifold. The rubber connections on the tubing get old and crack, and then leak some disgusting stuff that looks like a small dog on an unhealthy diet left something on top of the alternator. The point is, you may want to degrease the engine before you start this job. The most unpleasant part of any work on these things for me is getting my hands clean afterwards. If I was a dentist I would be in real trouble because hardly a month goes by when I am not greased up from tinkering. When I did the engine mounts and the starter, I was about the filthiest I have ever been. Good Luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Same happened to my 81 300D. Alt light glowing dimly, etc. Replaced reg/brushes unit. Several months later, same thing. This time local alt/starter guy rebuilt the unit w/Bosch stuff. Cost of rebuild was about $65, including remove/re-install.

Just yanked the alt. out today. What a piece of junk setup that was. After 2.5 hours I started to get really ticked off. Had every bolt off from here to Kansas and the thing was still wedged in such a way that you couldn't release enough tension to get the belts off. Finally pryed them off and hopefully didn't damage them. I can't believe anyone designed such a stupid deal. Perhaps its my gray market machine coming back to bite me. Never have done the other MB that I have so I can't compare.

Not looking forward to reinstalling because there is virtually no maneuvering room up there.

Don

__________________
DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

Don,

I remember getting the belt off being an issue too. I rolled the engine over with the starter after I wedged the belt over the edge of the pulley. Took a couple of shots but it worked. Today I would roll the engine by turning the power steering pump pulley nut. It is very convenient, and you can do it slowly enough to keep the belt heading off the alternator pulley. I do not think it has anything to do with grey market variations, it is just a pain to get the belt off. I actually think getting it back on is a little easier, and using the power steering pump pulley.....there have been cautions against this as the potential to put a bending moment on the shaft of the power steering pump exists and that could cause an expensive part replacement. I have done it a few times now and if you are carefull I think you can avoid damage. The pulley nut is so accessible.

Good luck, and sorry I did not warn you about the limited travel of the set up. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

It just went out on my 87 SDL at 275,000, and of course 150 miles from home.

First indication of problem: dim red anti-skid light, climate contro went to default warm air. At this point BATT was down but diesel was running.


HELPFULL HINT if it happens to you:

I removed the voltage reg. (very easy to get to on the SDL) and noticed barely any brushes with one dull brush. I pull on it with a pair of pliers and got it out another 1/4 inch. I believe I stretched the spring behind the brush because it still had positive return pressure and it was out another 1/4 inch. With a jump start after replacing the temp-repaired voltage regulator, I was back on the road.

Jim:

Thanks for the added advice. Am attempting to put it in tonight and gearing up for the battle. I'm going to get my game face on and go for it.
I'll note the caution with the PS nut and consider that. $95 for the rebuild but that included the guy replacing the damaged brush on the voltage regulator. Would have cost me an additional $39. My rebuild place is a bit expensive but it is basically new now.
I sure do appreciate all the help. Man, my hands are simply not coming clean these days. 3 baths in fast orange to no avail.

Don

__________________
DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

Don,

That Diesel grease has to be the toughest stuff to get off. I have noticed that the stuff that was made with Mobil 1 comes off a bit easier than the Syntech 5W-50 I was using before Mobil put 15W-50 on the market. I have yet to see if there is a difference with hand cleaning with the grease made with Delvac 1. But I know what you mean. I have made presentations at work with hands that looked like I stole them from dead bodies and had them transplanted to my wrists. Lucky I had a suit on as I usually get that stuff all the way up and past my elbows. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Just got done at 1:30 a.m. The worst part for me was that I had the alternator back in within 10 minutes but it took hours to line up that upper bolt. I've rebuilt a couple of engines in my earlier days but nothing this frustrating. I'm thinking about going and watching the dealer do one just for entertainment sake.

Car runs great and the volts are right at 13.8 ...... very rewarding.

Gave myself a number of baths (face and hands and arms) but its not coming off. Scrubbed my hands practically raw.

Thanks again for the help.

Don

__________________
DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

One more thing: if you remove the alt. pulley, be sure to torque it down to spec when reinstalling. I didn't, it came off at 65 mph, and I had to drive 50+ miles with no alt or water pump! Note: two years later, car is still running fine- gotta love diesels.