Existing externally regulated alternator is dying, so help me decide on a replacement:

Same 10DN: Rebuilt one at Autozone with lifetime warranty is cheap but was clocked at 12:00 so positive terminal interferes with rear bracket. How do you reposition it without brushes popping out, etc.?

Upgrade to 10SI: Guess I could bypass the VR and change the connector as described in other posts. Pretty sure the positive terminal is in the right place, but not sure if really easier/better than reclocking the 10DN.

Upgrade to 12SI: Fan does not look "right" compared to the 10DN or 10SI. No big sound system or other power hogs so extra amps not really needed.

Would like to keep idiot light functional so no real interest in a 1 wire solution.

 

Just remove the four long thin screws that hold the case halves together, rotate the case halves with respect to one another, and replace the screws.

... And with no extra power needs, I'd vote for the original replacement -
It's a simple plug-in, no hassles, and your car will still be original.

If the system's worked well for this many years, why change it all around?

Also - are you sure you need a new alternator, and not new diodes or brushes?
All of those parts, and the bearings, if they're bad, are easily available, and are even cheaper than buying a rebuilt.

- Eric

 

What are you running now? If it's an AC car you're probably 63A? I replaced my 37A last year with a 63A because I'm adding power options. The alt has the DN, not SI connector too so it was direct plug in. The alt is a good rebuilt AC Delco for the same price as an aftermarket. Don't care about the stamping date on the case - the part looks stock. I kept my original alt because there was nothing wrong with it. Have you considered just rebuilding yours?

 

Thanks Eric and was I hoping it was that easy to change the position on the 10DN. I'll bet it's just diodes but for $50 and a lifetime warranty I'll replace it all without opening the case.

 

Who gives lifetime warranty on electrical??

 

Advance Auto and NAPA do.

I'm on my third Advance Auto Lifetime Warranty Starter and my third NAPA Lifetime Warranty alternator in my Grand Cherokee.

On the one hand, top-of-the-line new units might have given me more than a year of service per unit , but on the other hand, these were cheap, and they're not too hard to change when they inevitably go.

- Eric

 

Does the new one have a pulley on it? Some do some don't.
I would pull your old one apart and check the brushes. Cheap and easy to fix if your alt still looks good.

 

A whole year of service from a new part? Well knock me over and call me Nancy. I buy quality parts, install them once and I'm done. Bought a replacement BOSCH alt for my wifes Saturn back in 07. Original lasted 11 years. The bosch has been in 4 years and still going strong. Installed new brake calipers, rotors and pads in 08. 35K later they're still going strong - no letdowns. Like you, our climate is just brutal at times and parts have to be good to last.

Changing out alts or starters once a year? Are you nuts? No wonder they give you warranty - you need it for the cheesy quality you're getting. Otherwise they wouldn't be selling anything. Good thing you like to work with tools

 

Hey, if I can get a part for $100 that is guaranteed forever, versus a part with a limited guarantee that costs $300, I'm goin' cheap!
My work is free - if I'm not fixing one thing on my day off, I'm fixing another - and I'll take a $200 discount anytime.



- Eric

 

Warranties and guarantees are only worth so much. FWIW the bosch alt I bought cost me around 65.00 and has a 3 yr guarantee. That's past and I haven't had to touch it. I expect it will go another 8 + years because bosch makes good parts. Not sure if we're comparing apples to oranges because even the alt I replaced in my 98 cost less than 100.00 and it was new, not rebuilt. I'm surprised you would choose vehicles (grande cherokee) that have high cost replacement parts.

Goin cheap? Stacey David said it best on Gearz - "You get what you pay for" and he was referring to the choice of chinesium vs good old American made quality parts/tools.

 

Well, so as not to tempt the fates, let's just say that the number of miles on that car are far more than any normal person would expect it would sustain with just a few incidental parts failures .

- Eric

 

I agree with Nancy. Advance also sells better quality parts like Bosch and Delco, but they do not have a lifetime guarantee. That should tell you something. Better keep the reciept and hope you don't break down very far from home or in bad weather. I own an alternator rebuilding shop. Advance moved in next door to me. I know what the lifetime electrical parts are made of, It makes me shudder. Advance moved in 12 years ago, they vowed to put me out of business. I now have a lot of advance customers that got tired of doing the job 2 or 3 times. Advance now sends me customers when Advance can't figure it out or are confused which is often. I love it when they install a battery backwards. Advance has been good for business. Be nice to the Advance guy because it is not a lifetime guarantee---It is a LIMITED lifetime guarantee. Read the fine print. They are only obligated to replace once over a lifetime. They may just refund your money and not replace the part at their disgression.

 

I thought there was more to the story.

So, just out of curiosity what goes into a 'better rebuilt' alt compared to the stuff Advance is selling? I prefer to have quality in my car because I need it to be reliable ALL the time.

 

Start with the quality of the parts used. This is not to say aftermarket components are all inferior. Some parts are better than OE. The better parts cost more. Example bearings--I can buy a bearing for $1.00 or one for $3.00 The difference the composition of the metal different steel. tollerances manufacturing methods and quality control. With the $1.00 bearing it may be a sloppy fit or noisy right out of the box new. The 3rd cheepo bearing may fit and be quiet, but I still have a cheepo bearing. I prefer to use the $3.00 bearing and do it once knowing I have a quality part in there. Plastic VS steel for some parts. Loose rivets VS screws and bolts for attaching parts. Not a good thing with a loose rivet on electrical connections. Add up all the individual parts in an alternator and you have a lot of possible failure points. Starter bushings Different materials. Cheap ones are brittle and wear FAST. Good ones are softer and are oil impregnated. they secrete oil when hot. They will outlast the cheap ones 3to1 easily. Solenoids Lower grade of copper inside for contacts, and the cheap ones have 100 turns of wire the good ones have 130 or more turns. That is a BIG difference. There would be a whole lot less hot start problems if the good solenoids were used. Guess which parts are in the low cost alternators and starters. Last is craftsmanship and pride. Go ahead and buy the Chineesium one every year for your proud American made car and keep the Chineese economy booming, jobs over seas and americans broke. Soon quality will be a thing of the past. It has already happened with the regulators for the old generators. It is almost impossible to buy a really good one now. Is that all you ask? no there is a lot more, but my fingers are getting tired. Pick a part and I will be glad to show you the difference in price of cheep VS quality. I know we like to think all men are created equal, but all starters and alternators ain't.

 

Mark, I am getting a sneaky suspicion that the starter I bought from you is going to outlive ME!

 

Only if you are over 60. Sorry about the rant.

 

Eric, I understand your reasoning. I know from your posts you are a good mechanic. I rebuild for a living. My customers would hang me if they had to replace the part every year. I can't afford to sell inferior parts and work for free. I had a customer on Monday with a return alternator from a VW golf. He complained it only lasted 5 years. He asked me how long it should last. I replied well your car is 10 years old and the original lasted 5 years and the rebuilt lasted 5 years so I guess about 5 years. Actually the rebuilt would have lasted longer, but he had an oil leak which saturated the inside of the alt causing the copper slip rings to burn. The oil causes the brushes to arc and wear prematurely. There was no copper left. He also admitted there were more miles on the rebuilt than the original. So there you have it. Advance does sell the better parts, but they give the customer what they want (a low cost product) and then the customers bad mouth them saying they sell junk. Like Allan said you get what you pay for.

 

Key part right there....most people say they want quality, but their actions speak volumes

I run into this all the time in my business....not all products are the same...Home Cheapo is the same as some of the Auto Parts stores...sell inferior products at a cheaper price...some people get it, others don't.

 

Mark, I'm not arguing with you at all.
You are absolutely right, and there is no question that a high-quality rebuild is far better than a crappy one.
I'm only saying that in my particular case of running a number of high-mileage vehicles for minimum investment, I'm happy to spend five to ten minutes every year replacing an alternator in exchange for the assurance that I only had to pay the small price of entry once (and, yes, I am friends with my parts counter guy ).

On the other side of things, the alternator in my BMW went out a few months ago (only had 160,000 miles on the &*$% thing...), and I took it apart, found the bearings to be sound, located a Hella brush / regulator set for $40 at the one local store that could get me one, and just changed that. I also kept the old one because it's obvious that the only thing wrong with it is that the brushes are worn, and when I get time I'll figure out how to open it up and change them, and where to get a new set, and I'll keep that one on the shelf to use in another 160,000 miles .

- Eric

 

Only 160K what a shame. Maybe you should complain to BMW but then again they might want it back to see why it lasted so long. A lot of later model alternators have some darn nice technology that allows them to last a lot longer and put out higher amperage. The technology also allows for longer battery life and even bearing life for other components like pumps on the same belt. On some models the pulley alone can cost upward of $80.00. It is amazing what they can do with the new technology, but it can also cause problems. Last week another rebuilder not far from me called to say he had a Volvo that he bought an alternator for from a parts store. The alt bolted right up plugged right in and charged, but the lite stayed on. he took it back for another one and the same thing happened. The problem was it had the wrong regulator in it. The reg wasn't communicating with the computer. I gave him the correct reg and all is well. The alt is computer controlled and reads a digital signal from the alt. The computer will moniter the battery state of charge the temperature electrical load and engine load and control the alt accordingly. I recomend anyone buying an alt for later model cars keep the old one until you are sure the replacement works. Nippondenso makes an alternator with square wire. This allows them to pack more wire into the stator to make a higher output alt of the same size as a round wire alt. That is so simple it makes me mad I didn't think about it 100 years ago. Now the cheap alts will most likley not have the right pulley on them. I guess it isn't a big deal unless you take into consideration the alt won't last as long nor will the belt the idler pulley bearings the belt tensioner water pump Ps pump and noise level. This makes the extra $ for a quality part seem like the less expensive way to go. What year model and engine is your BMW?

 

Eric. how were the slip rings? Grooved out? If you want I can send you brushes for the reg. Maybe even the slip rings if needed. The brushes are free for you, but the slip rings may cost a few $. Actually, you could probably make brushes from another car work if you sand them down to fit provided the lead is long enough. Mark

 

Mark, the stock alternator in my 78 Pinto lasted 150575 miles until the brushes wore out. I bought a set from the corner store for 5 bucks and had it all fixed up, in about an hour... Not sure how the charging system is designed on this car but the last battery lasted over 7 years!
Starter is original, never removed! When it does die, I will send it to you for a rebuild...

 

Yeah. It was a French-made alternator.
A German alternator should last "a thousand years," no?
Although, now that I think about it, it did last a bit over twelve years, which is about how long their "thousand year" products have lasted in the past.

I will admit I was a bit surprised when I took the belt off and spun the shaft - it was very gratifying.

Arrrrrgh!!! Stop! Brain hurts! Brain hurts!!!!


It's a '98 318ti with an M44.
The alternator is one of those with the commutator outside of the case in back.

Yup, they were a bit grooved.
The new carrier didn't line up exactly where the other one had been, so the new brushes rode on the high part for a while - I'd imagine they've worn in by now, the voltage has been fine the whole time.

Well, gosh, thanks!
I could measure the old brushes - I just haven't peeled off the adhesive / insulating gunk and unsoldered the leads yet.
I think ideally, it would be better to run the original regulator, because the darn brushes would wear less than they will with the current step-off.

I'll have to PM you...

Thanks!

- Eric

 

Bought a rebuilt 61A 10DN from O'Reilly with their lifetime warranty at lunch and will put it in tonight.

Would have gone the rebuilt route if I had the original core, but the one I pulled was a non-Delco oddball from who-knows-where. Case looked like a 10SI but had the parallel connector with the external regulator still hooked up.

 

You did good. That is an expensive alternator. No replacement brushes are listed for that. i am sure you could make them from another brush. The OE reg costs around $40 and a good aftermarket one is about $10 less. The OE should be a better fit. as you see. I think your alt is a pretty straight forward alt with no exotic pulley or controls. No slip ring replacement listed either. That would be an in house repair. There are a couple of ways to do it. Neither one very easy. You may as well run it like it is as long as you can.

 

Thanks - that was what I figured.

I bought the more expensive Hella regulator for $40 because I didn't want to mess around with eBay crap (have to remove half the engine to get to the alternator ) - they didn't list a Bosch regulator, and the alternator itself is a Valeo (French, as I mentioned), which wasn't listed either.

I figured I'd just remove the old brushes and measure them, then find others the same size (how many sizes can there be?).
I'll let you know whenever I get around to measuring them, and see if you've got a listing for that size.

As for the commutator, I thought of cutting it on a lathe, but I didn't think the risk of going through the metal was worth it, seeing as how it worked anyway the way it was.

Thanks again for your offer, Mark!

- Eric

 

Dane let us know how it works out. The case you took off was only made for a year or two. it looks like a 10SI but is a 10DN I think 71 and 72 were the only years that style was used.

 

Eric, since you have a lathe, you may be able to repair the slip rings yourself. A little tedius, but you can do it. If the time comes I will talk to you about it.

 

Thanks, I'll remember that, if it comes to it. I figure that since the surfaces are smooth and concentric (and since I cleaned them with ScotchBrite and lacquer thinner before I put it back together) it should bed in well enough to not cause any problems.
I've turned commutators on other motors before - the interrupted ones where you've got to carefully clean out the insulators in between the segments afterwards - and it was very straightforward.

- Eric

 

Would that case be the same for all the 71/72 alts (37/55/61/63 amps)?

 

No some 71 and 72 alts were internal regulated 10SI The 1st 10SI was made in 1968 probably for use in the 69 production year. 69 also had the early style 10DN external reg. As far as all 71 and 72 10DN cases being the same case (10SI type) I am not sure, but I will look into it and let you know what I find. The difference in the back part of the case is minor. If you look where the plug is inserted into the alt, you will find a small round prong or tab on the 10SI and there will be no prong on the 10DN. So you can make a 10DN case from a 10SI case by removing the prong, but not vise versa. I will try to put up some pics tomorrow. I will show 3 different 10DN alts and show the difference betweebn the late 10DN case and the 10SI case.

 

Rebuilt alternator installed and working well. 14.2 volts across the battery at idle. We'll see how it does long term.

The one I pulled was an oddball, maybe from Tuff Stuff since I saw some reciepts from the previous owner. No numbers anywhere or "Delco" in the casting. Voltage was all over the place and went through 2 VR's, then voltage dropped and GEN light came one. Good riddance...

 

Thats great. There is nothing like a quick fix.

 

The first is a 10DN for trucks
The 2nd is a 10DN everyone has seen. This one is actually a 105 amp factory made 10DN It has factory matching stator and rotor not up graded with 100 amp stator and 94 amp rotor like you see advertized . It is for sale if anyone is interested.
The 3rd one is the later 10DN style that looks like a 10SI. Look close where the plug goes in and see the little round tab is not there like it is in the last pic which is a 10SI The 10SI uses this to support the plug.

I found 1971 dated alts with the early style and the late style 10DN. The only 72 alts I found for 10DN were the late style.

4 more coming

 

the rest

I did my first 10DN to 10SI conversion in1975. I wish then I knew how many people would be doing it. I'd be rich by now.

 

Both of mine look exactly like the 3rd pic (first set). Now I have to ask. (mostly because I'm not an electrical guy). If both cases are the same, what determines the Amps the alt will put out? Is it the windings on the stator or the diodes used or something else entirely?

 

amps are determined by the stator and rotor