Hilarious part of the "long bolt" w/ 13mm fancy collared nut is that it combines several weak links at one application. Ears on the bracket bend and snap. The threaded long skinny dowel always bends out of shape. And it pulls or loosens the alternator in skewed fashion at one end only, with zero leverage at moving the rear portion of the alternator. Even if you actually try using this ridiculous adjust nut method to tighten belt tension you're better off leveraging the alternator from the engine block at the same time.

But whatever you do gotta loosen 3 x 17mm nuts'n bolts first. Then if you want to play with the absurd 13mm adjust nut it's up to you. And dont even think about removing the alternator with the goofy 13mm adjust nut/long bolt in place. With the crazy "L" bolt installed it's actually easier to remove the alternator and its bracket together at the same time. Quite the hassle compared with just pulling a few 17mm bolts and sliding the alternator out its bracket.

And the 13mm adjust nut is reponsible for misalligned alternators, bent bracket tracks where the alternator slides and general sloppiness at maintaining belt tension. It's easily the most frequently cursed nut'n bolt combo on the w123. Dunno why anybody bothers with it, i really dont. Without this crazy device in place, you just loosen the 17mm bolts then *manually* leverage the alt to tighten the belts and then retighten the 17mm's - easy as that. And no fumbling and guesswork with the feeble threaded dowel and 13mm combo that will in fact bend your alternator bracket out of shape.

I agree that when used improperly or aggressively that bolt combo really can wreak havoc on parts. but what usually causes it's demise is misuse. properly lubed and not over tightened. the thing works. most times it's used to tighten an old belt to stop a squeaking belt that is way past it's prime. with a new belt, and proper tightening, it is fine. I can think of hundreds of ways to improve on the thing, but it does work.
Why did the power steering pump get such a nice tentioner, and the alt get such a sucky one? ... design not MB's fault? ok, then why is the A/C adjuster so good? who knows?
John

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Poorly engineered from the git-go, the alt belt tensioner. Worst case I've seen is where the adjust nut had skewed the alternator at an angle, the bracket was cracked at the track and alt housing had worn oval where the bolt runs through it. All of this I blame on the "L" bolt pulling the alternator by one corner only.

Gentlefolks,

In my opinion "PB Blaster" is the absolute best penetrant that one can purchase easilly.....I went to sea for 25 years, and "PB Blaster" works on old rusty salt water soaked 25 yo steel stuff......way better than Liquid Wrench that most are familiar with.......can looks like it's "snake oil", lotsa testimonials and stuff.....but it truely works well!!

However the absolute best penetrant that I have ever found is "Kroil".....Kroil can be found at good "gun shops", and sometimes at independant auto parts stores......Kroil will work when PB Blaster won't.....

Lest we forget....a little heat goes a long way as well....but not on electrical stuff......penetrant, heat, tap,tap, penetrant, heat, tap, tap, wrench it.....heating a bolt helps with capillary action to draw the penetrant up into the threads....tapping with a small hammer helps loosten rust.....

SB

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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Here's an update on the issue:

I ordered a voltage regulator from Fastlane and it arrived on Friday. I installed it and the problem still existed. My battery would show 12.4 volts or so before I started the car and then with it running, it would show 11.5 volts or so. If I put the headlights on, it would steadily decrease to about 9 volts or so. I cleaned the terminals and connectors really well, as well as the ground connection to the body. No change.

I decided to take the car to Autozone in the morning to have them do their system test. I pulled the battery and put it on a trickle charger overnight so that it would be ready for the test. I put the battery back in in the morning and ran my usual tests. And guess what? Everything was functioning properly. The battery read 12.5 volts before I started it (same as always), but showed 14 volts with the car running.

So....explanations? I took it to Autozone anyway and both the battery and alternator passed the tests. I've checked it every time I've run the car since then and everything is fine. I don't get it. I've always had trouble with electrical problems. The only thing that occurred between the last "failed" test of mine and the first "passed" test of mine was the overnight trickle charge. But the battery was showing 12.5 volts before I charged it. And even if it were low, shouldn't the alternator have been charging it up?

By the way, it's only been a week since I got this car (my first Mercedes) and I love it and am going out this afternoon to look at a '98 E320 wagon. What have you guys done to me???

-Flop

Oh, I never did tighten my belt because I can't get any of the nuts to budge. I've sprayed them with PB Buster multiple times and they still won't move at all.

-Flop

The difference between a generator and an alternator is an alternator must be supplied with voltage to "excite" the field winding to then produce charging voltage whereas a generator does not. The advantage the alternator has is that is will charge at low RPM's whereas a generator requires more RPM to increase charging rate. My thought is the battery was too weak to excite the field to then start charging. Trickle charging brought the battery up enough to "excite" or turn on the alternator. Jump starting an alternator equipped vehicle with a discharged battery can damage the alternator. Jump starting a generator car does not present this issue. I work at a new car dealership. We jump start cars weekly, if not daily. Whenever I jump start, I leave the jumper battery connected for a few min. to not stress the alternator and to excite the field to start the charging process within the alternator. An alternator "alternates" voltage from 110 to approx. 14.5 volts hence the name.

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.

I don't like to nit-pick, but I have to correct this a little.
The alternator actually generates alternating current, much like you use out of the outlet in your house. The diodes inside rectify that to direct current that the car uses(and that can be used to charge the battery), and the regulator limits it to the ~14 volts that the charging system uses.


Now if I could only figure out what it is about my MB that is playing games in the charging system, despite knowing that the alternator works, I'd be happy too!

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...

my boat doesnt leave the dock without pb blaster.
I just cant figure out an ole seaman in WVA so old he was deposited there after Noah's flood
And is sandpaper good enough on a polished belt for another year or 2????


Sigh I was hoping to hit 400000 miles by New Year but mabe by Valentines Day now 397892 and counting

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commercial fisherman diesel in my blood in my boats trucks and Dear old Dad has had me drivin them since i got my first license in 1968
1986 300 SDL 427654
1999 Chevy Crew Cab Dually 225423
1986 300 SDL 287000 Dad's
1987 190 Turbo 158000 Mom's (my inheritance)

Think of an altrnator as all of what you said, and a balancing act.

if the alternator is making any kind of voltage it's good. if it's NOT making ~14.4v then it's 95% likely you need a voltage regulator. the other 10% is belts or bearings. Bad belts won't allow the alt. to make high load charges, like when you have your AC on, it'll slip as more load is put on the alternator and your battery will die. if the bearings are bad, you will hear a horendous noise under load (if you're outside the car), and with belts off, it'll feel grainy when you spin the alternator by hand. ANY axial play in the shaft when you jiggle the pulley is a sign of failing bearings...

But those are just my observations.

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RIP: 80 300SD
RIP: 79 450SEL
2002 E430 4matic (212,000km)
2002 ML500 'sport'

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FACEBOOK: PANZER450

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Hello All

Most rechargeable batteries, car batteries included, will grow " dendrites " or " hairs " between the positive and negative areas of the battery.

Particles line up and try to bridge the gap between the oppositely charged area.

Kinda like those weird little cobwebs grow in the corners of your house when there are no spiders.


This is one of the reasons batteries loose there ability to hold a charge.

When a battery that has grown these " dendrites " is charged with sufficient amperage, the dendrites dissipate and the battery works better.

I have used this idea to rehab old batteries myself.

This can be EXTREMELY !!! DANGEROUS !!!

If you use too much amperage you will explode the battery.

Do not try higher amperage chargers unless you understand how this idea works.



Battery magic number 2

A rechargeable battery with multiple cells. ( a 12 volt car battery has 6 cells ) can have one cell not working as well as the others.

If you charge the battery fully you can equalize the charge over all the cells making the battery work better.

Auto parts stores sell chargers that will " equalize charge " a battery.

Basically they charge the battery to around 16 volts for a set period of time.

Again this can be VERY DANGEROUS !!!

Batteries can produce explosive gasses when being charged.

Please be careful and understand how to do this fully before you try it.

Thank You All

Until next time I bid you peace and happiness.
RichC

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When the power of love overcomes the love of power the world will know peace.
Jimi Hendrix