Dear Dieslers,

When I bought my 240D a few weeks ago, I knew it to have some sort of problem in the charging system. I put a new battery in it, and it starts fine now, but the charging voltage is low (12.2 - 12.5 V, even with engine revved). I replaced the voltage regulator, as many have recommended, but I predicted as I pulled the old one out, with it's perfectly long and unworn posts (brushes?), that it was not at fault. Indeed, when we fired it up with the new VR, the voltage was the same. Some have recommended taking the old alternator to an alternator shop to have it rebuilt, but I haven't found one nearby that has a good reputation. Now I think I'd like to replace the alternator. I'd like to put a 65 amp model in, and I don't know which one to choose.

The Denso and Bosch versions ($210 and $165, respectively) seem okay, but maybe a bit expensive? I've seen some other remanufactured ones out there for around $100. And how about this one on ebay ($50 + shipping):

http://cgi.ebay.com/ebaymotors/MERCEDES-BOSCH-ALTERNATOR-DIESEL-240D-300D-450SL1975-85_W0QQcmdZViewItemQQcategoryZ33573QQihZ003QQitemZ130124030067QQrdZ1QQsspagenameZWDVW

Does that seem like a bad idea?

Any advice would be greatly appreciated.

-Ravi

__________________
When I bought the 1983 240D with 250K miles, my father joked: "So, finally, a Mercedes-Benz in the family."

Facing a similar issue on my 77 300d. Are the replacements you are looking at the ones with the internal regulator? It seems to me that there is an advantage in keeping the external regulator since it can be changed without replacing the whole alternator.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Kerry,

I find the internal/external terminology to be a bit confusing. In my car, the voltage regulator is screwed to the rear-facing circular end of the alternator, i.e. the end of the alternator opposite the belt. On the other hand, the brushes extend into the alternator and abut the rotating slip rings, inside the alternator.

Is this "internal" or "external"?

In this setup, you definitely do not have to remove the alternator to replace the voltage regulator. It was very easy to replace: one jack-stand + 5 minutes for me, and I'm a total amateur. I used a stubby phillips head screwdriver, which was good for the narrow clearance behind the alternator.

The alternators I'm looking at all have the same appearance as the one in my car. They have the voltage regulator screwed to the housing of the alternator.

Do you think the cheap alternator on ebay is worth a try?

-Ravi

__________________
When I bought the 1983 240D with 250K miles, my father joked: "So, finally, a Mercedes-Benz in the family."

Also, does anyone know of a good DIY page on alternator replacement, esp. for a 240D? I know the basic steps, but I'd love to see some pictures.

-Ravi

__________________
When I bought the 1983 240D with 250K miles, my father joked: "So, finally, a Mercedes-Benz in the family."

The vendors of the rebuilt ebay alternators and starters in california usually have perfect feedback. You cannot even get that with more expensive ones. Worth the so called risk in my opinion.
Or there is a package of a rebuilt starter and an alternator combined for slightly under 100.00. Again the company has tremendous feedback. A lot of poor alternator and starter rebuilds come out of mexico to here. These are not them.

Barry,

Thanks for your input. I'd noticed the feedback and thought it looked pretty encouraging. I ordered a 65 amp reman for $50 + $20 shipping.

-Ravi

__________________
When I bought the 1983 240D with 250K miles, my father joked: "So, finally, a Mercedes-Benz in the family."

I may do the same thing. I took ours to be external regulators. I may be wrong. I was looking here at 'Buy Parts' and that's where I came across the internal/external issue.

I did it.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I bought an AL129x 115amp alternator rebuild fro California Alternator & Starter.. They primarily sell via eBay, but I bought it direct from them, so they cut me a deal (no eBay fees! ) for $100 with free shipping.

Very knowledgeable and the alternator seems pretty stout and works good. I asked one of the people and they said they disassemble, clean, replace all wear parts (bearings, slip rings, diodes, voltage regulators) and reassemble / test them. 1 Year unlimited miles warranty. FWIW, the bearings in my unit were definately new as they were actually slightly stiff yet....

A+ folks!!

__________________
-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

There is no core charge or core return required with these California companies. So you might also land up with a spare good regulator from your old unit before tossing it.
Since they install new slip rings their rebuilts should last for at least two regulators. Basically brush wear effects on the slip rings is the issue plus the slip rings remaining diameter if only machined. This was my primary concern at their prices.
If they were just trueing up the old slip rings. A small amount is fine but these old alternators in general have gone so many miles the wear is usually too heavy for that to be a good fix. Another concern was the brand of voltage regulators used in their rebuilds. Some poor brands of aftermarket ones drop out pretty early.
I finally decided with their feedback they knew and cared enough to buy fairly good aftermarket parts and probably checked the electrical balance of the alternator coils unlike the junk I have seen out of mexico where they do not seem to even bother.
Plus the mexican reuse of parts that are notorious failures on bosch stuff. Like used and not even rebuilt solinoids on their rebuilt starters for example. The mexican stuff is just looking for trouble in my opinion. Vended under far too many different labels in the USA and Canada unfortunatly.
I think the value for money component is excellent with the california rebuilders. Again their package of a starter and alternator for under a hundred dollars for 123 diesels struck me as exceptional value in todays market.
If you drive long distances a spare pair in the trunk with extra belts,filters etc does not strike me as stupid with a 25 plus year old car. Just try to buy a reasonable priced alternator or starter with good quality out on the road. Even if quickly available and the first one works its probably a mexican rebuilt because the margin is higher. Especially alternators.

For the "what it's worth" category. If you have the ability to R/R an alternator from your vehicle - you have the ability to rebuild it yourself at a fraction of the cost. They are not complex and the parts are inexpensive.

__________________
BENZ THERE DONE THAThttp://www.peachparts.com/shopforum/...c/progress.gif
15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)

Deere, Barry, thanks for the tips on CA-rebuilds. They seem like a good thing to know about. And I agree that having a spare alt. in the trunk probably isn't a bad idea.

TX, since I'm not going to have to return my current alternator, maybe I should rebuild it. How would a guy go about learning how to do such a thing? Is it in a book somewhere? Or do I have to seek out an alternator-rebuilding hermit in the swamp somewhere?

-Ravi

__________________
When I bought the 1983 240D with 250K miles, my father joked: "So, finally, a Mercedes-Benz in the family."

Here is a link to Bosch repair. While specific to Land Rovers the concept is the same.http://www.rangerovers.net/repairdetails/electrical/boschaltrepair.htm
While most of us know the simplicity of replacing the brush pack - bearings and diodes are the rest of the story. Many years ago I took an alternator to the local 1 man alternator shop. He said it would take him thirty minutes if I wanted to wait on it. He allowed me to watch him test, inspect, and crack it open to replace the necessary part. After that I decided it wasn't necessary to send them out anymore.

__________________
BENZ THERE DONE THAThttp://www.peachparts.com/shopforum/...c/progress.gif
15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)

Practical self rebuilding depends on availability of good parts reasonably. Just digging in and finding the fault might be practical for the averge guy if he is interested. Certainly a sound used alternator should never be replaced just for faulty bearings. These are available at most bearing houses.
These older mercedes bosch alternators are usually high milage with severely worn slip rings. An individual may have some trouble in this area. Older volkswagon products display the same problems. Several good instructional guides are probably on ebay. Never hurts to try. The comfort level of different individuals will vary. On the otherhand when you are not confident you are learning.

Guys,

I replaced the alternator yesterday, and it went very smoothly. The PO replaced the alternator half a year ago, but the alternator I pulled out showed significant wear: the body and fan are rusty, the pulley is warped and rusted. I'm not sure where he got the replacement, but now it's no wonder that it needed to be replaced again so soon. The CA alternator I got looked beautiful, and now it outputs a nice 14 V when idling.

Thank you all for your help and advice.

-Ravi

__________________
When I bought the 1983 240D with 250K miles, my father joked: "So, finally, a Mercedes-Benz in the family."