Recent Alternator Work?
 

I got stranded near Toledo coming back from PA en route to Michigan yesterday. The car was running fine but lost the ability to charge the battery. Therefore, no wipers, lights, etc and with the incoming snowstorm (and darkness), my wife did want to risk it. Dropped it off at my cousins and worked a bit trying to get the alternator off. We eventually caught a ride by my brother but the car is still there.

Has anyone done this recently? What bolts are necessary and which ones can I avoid? Do I need to remove that tensioner bolt etc?

Thanks,

Don

Iwould always try a voltage regulator first as it can be done in less than 10 minutes. Only a screwdriver is needed. Also after starting try un-plugging the glow relay as they sometimes stick & take ALL of the power the alternator can produce!! Good LUCK & happy New Year!

re:alternator
 

I agree with M.B.Doc- My '80 300SD (299,000k) had exactly the same symptoms. After talking the local mechanic out of pulling the alternator for possible rebuild (MUCHO $$), I got him to check the brushes in the voltage regulator - 10 minutes and $30Cdn later, I was on the road, with everything working better than since the day I first bought the car. Good Luck!:D

I've had 2 Bosch alternators fail in 2 of my 300D's. What I have found is, if your battery light is NEVER ON, while driving or when turning the key to glow the car, the it is NOT the voltage regulator.

1. Loosen the bottom "pivot" bolt on the alternator
2. unwind that tensioning screw
3. Take out the bottom bolt and the top pivoting screw
4. Remove and replace

Its about $150 with a $75 core charge. I have two in my basement I never sent back..

The first time I did it, it was a little tough. Then the second one I managed to bang out in about a half hour.

Ditch the Bosch it is sh..t Go get the cheapest 55 amp Delco-Remy $29.00 , and put it on , you'll never stop thanking me. No external voltage regulator no fuss no muss. Any child could rig up a mount and interpret the schematics. And when that wears out ( NEVER) you can fix it.

Might check for a loose or broken wire too.

Hi Don

I agree with changeing the regulator. You can do it with the alt still in the car. To check, see if you getting 13.8 volts at the battery. If you are not, change the regulator. You can easily snag one off of any Bosch alternator in the junkyard, doesn't have to MB. Could be BMW, Audi, VW, Peugeot, etc.

All you need is a flat screwdriver. Here is what you do.
On the back side of the alt, you will find an electrical plug, pull it out so it out of the way.
If you use a mirror and a flashlight, you will see a round black thing with two wings, one on either side with a slotted screw in it.
Back out the screws- catch them before they fall in the snow:( and pull the regulator out. It sort of tilts out, you'll see.

To install the new one, the brushes will be longer so when you tilt it into the opening, you might have to push it a tad to get one screw started. Screw that screw almost all the way in, then swivel the other ear over the screw hole. When you swivel it, you will feel the spring tension on the new brushes resisting. It's okay. Run the screw home and that is it Brother!!!

Hey Presto, you should be getting 13.8 volts to the battery or more if batterey is discharged.

Thanks a bunch for the help so far. I was off-track a bit thinking that the grey market regulator might be different. Based upon all your data and a comparison with my 84, I think I'm back on track.
Will be popping off the plug on the back of the alternator tonight. Will post my results but I suspect the regulator as the battery light is flickering.

Don

I'm having a similar problem in that my battery light turns on late and slowly gets brighter and doesn't go out. Snagging a Bosch alternator from a Euro car is a brilliant ideal 240 Ed! But will any Bosch do, is there not different sizes and amp ratings? 240 Ed have you tried your idea in practice? If it does work I could save some real money if my alternator really is toast.

And diesel don keep us informed.

The regulator regulates the voltage, not the amps. You should be getting 13.8 volts when the engine is running about 1100rpm and above. You won't get any more volts at higher rpms.
There are two common Bosch alternators of two different amp ratings. One is bigger than the other as I remember, but quite rare except in say a big Audi or MB probably.

The regulators are all the same. I have interchanged regulators many times. Some look a little different because they are from different manufacturers, but they all mount up the same. Look for the longest brushes you can find, and grab more than one!

The alternators have different mounts, depending on the car.
What I have also done on these alternators, is take them apart and swith the mount sections and bolt them up again. You have to sort of try it. It's not hard! You take out the two long skinny bolts on either side of the alt which holds it together like a sandwich. Tap it lightly to separate, and see if things will go together and match up. You can also change out the bearings! Take one to your local King Bearing store and match it up! about $7-$15 for two! I paid $7 about 10 years ago.

With Pick and PUll prices so cheap, you can experiment with stuff like this--I hope you have access to this type of yard!!!!!!!!

Thanks!
 

The truth is that you guys are awesome! I took out the voltage regulator and the brushes were trashed. After my fourth store, I found a new one for $39. Reinstalled it and tried out my new voltage meter and 13.78, 13.79 and 13.80. A very cool digital toy.

I'm back up with all three diesels. What are the odds that I'll get a couple of weeks off from mechanic world?

Thanks for all the help along the way.

Don

I have found that usually it's the brushes that are worn down and the regulator itself is fine. Just buy a set of brushes, and solder them in. Total Cost around $3.00.

I found the brushes at a local auto parts place. I think it was NAPA.

Joe

That is a great idea. Wish I would have tried that first! Anyway, one can hardly argue with $39 compared to taking it in.

Thanks again,

Don

It's been awhile but I think I soldered the leads such that the brushes can't get out of the track. Adjust the length and solder to keep the brushes in. Once the assembly is in the alternator, all tension is removed from the leads.

If you can solder, just buy the brushes and put them in. If you can't or don't want to mess with it, buy the regulator assembly.

I thought I was the only one that noticed that if the brushes fail, you don't get the battery dummy light, at least one bright enough to see during the day.

My brush fix has gone 65000 miles and it's still working fine. Total cost about $3.00.

Joe

My brush job has gone 100,000+ miles and 10 years but I wouldn't surprised I will need a new set soon.

P E H