which reman alternator? - PeachParts Mercedes-Benz Forum

Jack None · #1 10-06-2014, 12:12 PM

My alternator seized and I need to buy a replacement. The McAuto stores have remanned units for about 90 bucks, remanned Bosch units are available for around 140 bucks. What are your experiences with these options?

Also, is there a way to get the alternator out of the bracket without removing the difficult-to-access top bolt next to the engine?

This alternator was 30 years old and due for replacement anyway, but I wonder if I messed it up when I replaced my water pump 5000 miles ago. I slacked the alternator to get the belts off, then retightened. I wonder if I sent the bearings to an early demise by either getting coolant in the unit or by overtightening the belt.

Jack None · #2 10-06-2014, 12:25 PM

Ha, just read the earlier thread about reman starters.

I could order the Bosch, but I wouldn't be able to have it tested before buying. If I bought from McParts at least I could have them test it before I walked out.

I will also see if there is someone local who could rebuild mine in a reasonable amount of time. It wasn't charging great, though, either. I assume a competent rebuilder could fix both problems, weak charging and seized bearings?

JamesDean · #3 10-06-2014, 12:54 PM

Weak charging could have been a result of the poor condition bearings. It could have also been caused by worn out voltage regulator or even too much load on the system (which is possible in the factory configuration).

Would you be opposed to upgrading the alternator? Since you have it out you might as well look into the possibility of installing a higher output unit. I've got one on my 300SD and it works quite well.

I've had good luck with rebuilt alternators from AutoZone. Last time I went through Advance Auto Parts I went through 3 of them before getting a long lasting one.

Jack None · #4 10-06-2014, 03:02 PM

Thanks for the response, JamesDean.

Does a slightly larger unit fit in the bracket?

JamesDean · #5 10-06-2014, 03:11 PM

Yep.

Here is a thread discussion the AL129X alternator:
"Alternator" 115 Amp Bosch AL129X works in 123s!

I installed one in our 420SEL and 300SD (can't find the photos)
420SEL: http://imgur.com/a/wP7GX

Dan Stokes · #6 10-06-2014, 03:45 PM

I've had excellent results from our local rebuilder and I'll wager you have one in your area, too. They KNOW they'll have to deal with you if the do a crappy job and they definitely don't want bad word of mouth. Our local guys are just a tad more $$ than the Big Box stores and, in my estimation, worth it.

Around here it's Coastal Rebuilders in Wilmington, NC but I bet you have someone, too. Usual turn-around is 1-2 days unless odd parts are required (they had to order something for mine and I think it took another day).

Dan

SD Blue · #7 10-07-2014, 10:38 AM

It is much easier to remove the alternator and adjusting bracket as a unit rather than trying to separate the alternator from the bracket while still in the car.

mach4 · #8 10-07-2014, 10:43 AM

^^X2. Definitely the way to do it.

PARSHOOT1 · #9 10-07-2014, 07:33 PM

2x Dan Stokes comment.....find a good local re-builder. And if you don't a recommendation for a local shop under the MB section of Pelican check the BMW or Porsche sections. They'll probably have a rec.

Mxfrank · #10 10-07-2014, 08:26 PM

The problem with upgrading the alternator is that you should also upgrade the wiring harness. While your car won't draw 115A ordinarily, an unusual condition, like a flat dead battery could draw the full output. If you have a v-belt driven alternator, you really should covert to a serp belt for anything over 100A. this isn't always easy.

The fallacy is that 65A is inadequate for a Diesel. It's not. The only reason you would need more is if you've added something like a 1000W radio or a light bar. A 123 has no electrical ignition system, no electrical fuel pump, barely relies on the electric aux fan, has no ECU, no airbags, in fact, almost nothing that uses lots of power. You have A/C, which may draw 10 amps with the fan on high, exterior lights, which might draw 14A on high beam, a puny radio, and a scattering of interior lamps. If you throw every switch, I bet you'd barely crack 30A. The glow plugs and starter pull quite a bit, but from the battery. If your alternator has 35A of headspace, then you'd recharge the battery in about five minutes after a cold start.

spdrun · #11 10-07-2014, 09:08 PM

Does A/C automatically run the aux. radiator blower when the compressor is kicked on? That might eat an additional 20A.

Also, at what engine RPM does the stock alt put out 65A? I wonder if some of the people who complain about it being inadequate do a lot of stop and go driving in summer.

Jack None · #12 10-09-2014, 02:31 PM

Alright. I found a neat place in downtown LA -- in business since 1962 -- with a reman replacement. So that's good.

But I'm still scratching my head about getting the old alt out. I haven't been able to break the driver side top bolt free, because the stub of the passenger side top bolt, and the turbo intake hitting the handle of my tool, aren't giving me enough room. It's barely one ratchet click worth of space, so my breaker just flexes and runs out of space.

If I could get the passenger side top bolt out (the one with the delicate threaded adjuster rod coming out of its head) I think I'd have it. But I haven't even been able to get the adjuster nut off, because the threaded rod starts to bow. So I'm not sure how to get the passenger side bolt out. Some folks report being able to take that bolt off and remove the alt without removing the driver side bolt, because (for example) they didn't have room to back it out after loosening it.

What would you advise?

SD Blue · #13 10-09-2014, 02:57 PM

Quote:

Originally Posted by Jack None

Alright. I found a neat place in downtown LA -- in business since 1962 -- with a reman replacement. So that's good.

But I'm still scratching my head about getting the old alt out. I haven't been able to break the driver side top bolt free, because the stub of the passenger side top bolt, and the turbo intake hitting the handle of my tool, aren't giving me enough room. It's barely one ratchet click worth of space, so my breaker just flexes and runs out of space.

If I could get the passenger side top bolt out (the one with the delicate threaded adjuster rod coming out of its head) I think I'd have it. But I haven't even been able to get the adjuster nut off, because the threaded rod starts to bow. So I'm not sure how to get the passenger side bolt out. Some folks report being able to take that bolt off and remove the alt without removing the driver side bolt, because (for example) they didn't have room to back it out after loosening it.

What would you advise?

Read post #7. It is considerably easier to remove the alternator and adjusting bracket as a unit then separate them after they are out of the car.

Trying to separate them while in the car usually ends up with a damaged ~$70 adjuster bolt.

pawoSD · #14 10-09-2014, 03:44 PM

Try idling a stock 617 vehicle with a 65A alternator on a freezing cold day in the evening with the blower on high, headlights, fog lights, radio, rear window defrost, etc...and you will see the load FAR exceeds the 65A output especially at idle. The stock alternator is very inadequate for those situations. I installed an 80A and it just barely cuts it in those conditions, it will hold about 13.1V at idle with those items on. The 65a and 55a will fall to about 10-11volts and drain the battery.

Quote:

Originally Posted by Mxfrank

The problem with upgrading the alternator is that you should also upgrade the wiring harness. While your car won't draw 115A ordinarily, an unusual condition, like a flat dead battery could draw the full output. If you have a v-belt driven alternator, you really should covert to a serp belt for anything over 100A. this isn't always easy.

The fallacy is that 65A is inadequate for a Diesel. It's not. The only reason you would need more is if you've added something like a 1000W radio or a light bar. A 123 has no electrical ignition system, no electrical fuel pump, barely relies on the electric aux fan, has no ECU, no airbags, in fact, almost nothing that uses lots of power. You have A/C, which may draw 10 amps with the fan on high, exterior lights, which might draw 14A on high beam, a puny radio, and a scattering of interior lamps. If you throw every switch, I bet you'd barely crack 30A. The glow plugs and starter pull quite a bit, but from the battery. If your alternator has 35A of headspace, then you'd recharge the battery in about five minutes after a cold start.

oldsinner111 · #15 10-09-2014, 03:46 PM

I use advanced auto parts alternators,and starters.Run for many years no problem.