Alternator? And is this something I can do? - Page 2 - PeachParts Mercedes-Benz Forum

rs899 · #16 08-24-2011, 12:23 PM

It's just getting to the 2 screws (see post #11) on the back of your alternator. That's IF it's not charging at 13+ volts ....

imagesinthewind · #17 08-24-2011, 12:27 PM

Remind me (okay teach me) how to tell if it's charging at 13+ volts?

I once arched between my wedding ring and a screwdriver while working on my
VW bug engine. Ring burned through my finger to the bone. Got white on my hand and there was no way to get the ring off since it was burned into my skin.
The scar is interesting. . . covered by my new ring.

rs899 · #18 08-24-2011, 12:29 PM

Take your voltmeter and adjust it so that it reads DC volts on a scale close to but above 12 volts. Touch the red (+) lead to the positive and the black (-) to the negative terminal. Read voltage. Do this with the car off and then with it running at a fast idle and tell us what you got.

imagesinthewind · #19 08-24-2011, 01:26 PM

Okay, doesn't seem too good.
Car off, the meter reads 12.73, a regular idle reads 12.34 and fast idle reads 12.57.

Is that volt reg or alternator?

BTW, I LOVE YOU GUYS!!!!! LOL!

rs899 · #20 08-24-2011, 02:05 PM

Most likely it is the regulator/brush assembly which is IN the alternator (see post #11). The rest of the unit is pretty robust and you can usually replace the regulator/brush 2 or 3 times before you have any other problems. See if you can get to those 2 screws and get it out and take a look at it.

Zulfiqar · #21 08-24-2011, 02:12 PM

by those readings your voltage regulator is bad. the windings are not even exciting to produce any sort of generation.

replace the regulator with a new item, and retest. If not working, then measure the voltage at the bulb connection wire, it should be 14.0 V - if not apply a test lamp to it with its tail on positive. It should kickstart the alternator. If still no juice, then removal and tear down or another item is your answer.

had a VW diesel that had a similar 90A alternator that would not charge, a new regulator fixed that, and replacing it was deady easy as my car was 1.6 TD with A/C - the alternator was the highest mounted item.

imagesinthewind · #22 08-24-2011, 02:37 PM

Quote:

Originally Posted by rs899

Most likely it is the regulator/brush assembly which is IN the alternator (see post #11). The rest of the unit is pretty robust and you can usually replace the regulator/brush 2 or 3 times before you have any other problems. See if you can get to those 2 screws and get it out and take a look at it.

So, shinny under the car and remove the volt reg. Okay I can do that, but later. Think I can do it without jacking the car up? I'm claustrophobic under 5000 pounds. Thanks!

rs899 · #23 08-24-2011, 02:39 PM

^^ may be more accessible from the top

imagesinthewind · #24 08-24-2011, 02:51 PM

do I disconnect both sides of the battery or just ground?
it is an easy get from the top.
I just dont want to take the chance of arching myself again.

EDIT:
On line has it for $40-ish.
Advance no longer has it.
NAPA has one at the warehouse for $78.

How bad is it to charge the battery after using it for a couple days while waiting for Fastlane to deliver?

toomany MBZ · #25 08-24-2011, 02:57 PM

I don't disconnect the battery at all, but to answer your question, simply remove one of the cables, you break the circuit.

vstech · #26 08-24-2011, 03:20 PM

advance has the regulator for around 15.00... made in germany box with a made in china regulator in it.

Hey , you can support our wonderful site and buy it here!

our site has the internal regulator for 28

and the external one that mounts on some fenders... depending on which alternator you have in your car... for $44

rs899 · #27 08-24-2011, 03:29 PM

The nice thing about our cars is that they are 100% mechanical once you start them- no electronics. If you charge it, start it , don't use the A/C or lights, chances are you can get a few starts (quick ones) out of it before you drain the battery. So if you want to press your luck a bit, you can do without it for a bit if you conserve the electrons.

imagesinthewind · #28 08-24-2011, 05:23 PM

I ordered the internal one, it looks like the one on my car. . .now to hope it comes fast.

imagesinthewind · #29 08-29-2011, 07:12 PM

So, I got the volt reg today (Peachparts is SOOO fast to my house!!) and installed today.
I unhooked the neg on the battery so I didn't have to worry about arching myself while under the car. I did get under the car for this, though I could reach it from the top, I didn't have good room to get to screws out from there.
I checked the volt on the battery before I started and the meter read 12.03 at idle.

Here is the old and the new:

I drove the car for about 2miles around the hood and rechecked the battery, it read 13.30 the first time I stopped and checked. I drove the same block again and checked again and the battery hadn't changed. Do I need to recharge the battery so it's fully charged? Will driving 60 miles at highway speeds charge the battery for me?

Thanks!

rs899 · #30 08-29-2011, 07:37 PM

As long as it's charging ( at 13.3 )you should be OK. Good job.