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Thread: Alternator woes

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    Alternator woes

    Hello all. Excited to make my first post on this site!

    I do believe my Alternator is done or at least really dirty and not working. I have studied up on this issue (on another site) and believe my van passes the smell test:

    power steering pump leaking
    Very dirty alternator (sand, dirt,mud)
    Believe ALT is OEM and never replaced
    Battery has charge, but cannot start engine without a jump start

    What to do now: Do I remove alternator and clean it, then test?
    Buy new or refurbished Alt (denso)? Grab one at salvage yard?
    Is it best to replace power steering pump as well, if leaking?

    I am willing to pay to get a good one. Any info will help.

  2. #2
    Administrator timsrv's Avatar
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    Re: Alternator woes

    Hello and welcome to the site! FWIW, it's okay to mention www.toyotavanpeople.com here. I assure you the censorship between them and us is a one way street. I guess what works best for you will depend on your mechanical ability, your willingness to get your hands dirty, and your resources.

    In my opinion a damaged but original alternator is better than a working rebuilt one (the exception being an alternator rebuilt by Denso). The original alternators can usually be repaired for a fraction of the cost and will typically last longer than the "lifetime" rebuilds you find at the auto parts houses. If however you need something fast and don't have the ability to repair then a rebuilt one might work better for you. If you go the rebuilt/remanufactured route, I would just pay the core charge and save your original (perhaps you could fix it later and keep it as a spare).

    I understand the challenge of repair without the correct equipment. Unless you have a bench tester all you can do is disassemble, clean, perform a visual inspection, repair/replace as required (any obvious defects), and re-assemble. Once you think you got it fixed you can take it to an auto electric business for testing on a machine. Most auto parts houses also have the bench testing machines, but finding a sales guy competent enough to run it might be a problem. Some of your more reputable places like Napa have better trained counter guys and you'd have a better chance there.

    Before I got my bench tester that's how I did it. It's hardly worth making an investment like that for a single alternator repair, so taking it in for testing is probably the way to go. I got my tester because over a 10 year period I had collected 8 failed alternators . After repairing them I sold them for $40 each, so that helped pay for the machine (it's really more of a toy for me).

    Based on what you said I'm guessing it's just your brushes that have failed and the rest of the alternator could be fine. Brushes that fail due to power steering leaks are usually pretty obvious so I'd at least take the tin cover off the case and check those before going and replacing the entire thing. Whatever you decide, by all means repair the power steering leaks before putting an alternator back in there. For information on the common power steering pump leaks CLICK HERE.

    As for alternator removal here are a couple of good threads where this is discussed:

    https://www.toyotavantech.com/forum/...or-ILLUSTRATED!

    https://www.toyotavantech.com/forum/...atively-easily....

    Once your alternator is removed inspect the harness and replace if questionable. The round harness that plugs into the back of the alternator (with 3 small wires going to it) tends to get broken wires in it. Often times the wires will look good on the outside but the conductors inside can be compromised. CLICK HERE for more information on the alternator harness.

    Once out it's fairly easy to disassemble the alternator. Here are some pictures of what you can expect to find:

    These are your alternator brushes




    These are your brushes on ATF (power steering fluid)


    Alternator brushes are Toyota Part #27370-35060 and sell for about $15 - $30 (depending on the dealer). Another thing to check (2nd most common failure) is the diode assembly. Here is a messed up one off of a remanufactured alternator:


    If you look closely you can see several of the diode stems have desoldered themselves from the assembly. This is partly due to a low temp solder the rebuilder improperly used and partly due to the alternator being overworked (owner tried to use it to recharge a dead battery). I don't have a factory Denso diode assembly handy for pictures, but those are identifiable by a gray plastic coating Denso uses to protect from moisture. Even if your diode assembly looks good it doesn't mean it is. There are several diodes here but it only takes one to fail and you're dead in the water. Sometimes diodes short. A shorted diode will allow electricity to travel both ways. An alternator with a shorted diode will often still charge okay but will also discharge when not in use. The easiest way to test for this is before you remove the alternator. Go to the little plastic "+" box (under & slightly forward of your air intake tube) & open it up.





    Being careful not to touch your tools on any other metal surfaces remove the 10mm nut from the stud. Now remove the eye terminals from the post & touch them together. If they spark or arc, then you have a shorted diode and the diode assembly will need to be replaced. Protect these wires from touching any metal surfaces & before going any further disconnect the battery! Removing the alternator with the battery still connected can be very exciting .

    Even if the diode assembly passes the above test and it looks good, it could still have an "open" diode. An open diode is one that will not conduct electricity in either direction. Testing for an open diode is easy IF at least one side of the diode is disconnected. Unfortunately since these are soldered with a high temp solder disconnecting them for testing is not an option. The only way I know how to test for this is to put the diode assembly into an otherwise good alternator and run a bench test on it. If the output voltage is low or not even there then the diode assembly is bad and should be replaced. I haven't priced diode assemblies, but frankly I wouldn't want a remanufactured one and I probably couldn't afford a new Denso one. For this reason I shop for them at the pick & pull salvage yards. It's actually pretty easy and inexpensive to find good Denso diode assemblies at the yard. Keep in mind that Denso made variations of this same alternator for many vehicles. There are many vehicles from this era that use internally identical alternators. The cases and mount configurations are often different but the internals are the same. This is good news because it gives you several vehicles to choose from. I've found several Toyotas and several Hondas (among others) to be 100% compatible (other than the cases). Just look at the connection locations on the back side and make sure the round regulator plug is a match.

    Another big advantage to this is these alternators are usually in good shape. Even if they have a bunch of miles on them they have most likely had a relatively easy life (cool environment and no ATF leaking onto them). I've pulled several apart with over 200k miles on them and found them to be original equipment and only in need of brushes. Another awesome thing is ease of removal. I always look for the transverse mounted engines that have the alternators mounted on the front side of the engine. These can be removed in just a few minutes. Most pick & pulls around here will charge $19.95 for the complete alternator, but I've found they will usually sell me the diode assembly for about $5. They will often just give them to me for free if I'm making a bigger purchase .

    Voltage regulators are the 3rd most failed component on these alternators. Here is a picture of one (left side of picture sitting on box):


    Like the diode assemblies, the only way I know to test these is by putting into an otherwise good alternator and running it on the bench tester. I've purchased these new from www.rockauto.com for around $20 on their close-out sales (Standard part#VR-405), but I actually feel a bit more comfortable with the used Denso ones from the pick & pulls. Again, they will usually charge me anywhere from $0 - $5 each.

    There are other parts inside the alternator that can fail, but these are the 3 big ones. It's been my experience that bearings, windings, etc will often go beyond 300k miles so why compromise reliability by replacing with a remanufactured unit? Here's a little video I made while playing with my alternator tester. Enjoy Tim


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    Re: Alternator woes

    Tim you are awesome, thank you sir!

    My alternator is out. It was my first attempt and only took about 40 minutes, some cursing and a deep breath. I followed llamavan's instructions found here: https://www.toyotavantech.com/forum/showthread.php?90-Change-your-alternator-ILLUSTRATED!&p=360#post360

    My next step is to examine brushes for potential damage. How do I pry the case open? It is really dirty, no wonder it stopped working properly!

    If I need to buy a new/refurbished one what is the model I am looking for?
    There are three sets of numbers on the alternator, two sets that include a hyphen (xx-xx) but some of the numbers on the sticker have been ripped off. The third set reads U145288.

    I will try posting pictures later.
    Last edited by momentum; 03-04-2011 at 05:36 PM.

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    Re: Alternator woes

    No need for prying and technically speaking you won't even need to open the case. Everything you need to access is right there under the tin cover on the back side.

    Take off these 4 nuts and pull the black plastic stand-off from the stud.


    Remove the tin cover.


    Remove these two screws.


    Remove brush assembly and then remove these 3 screws.


    Remove regulator assembly.


    Remove these 4 screws.


    Remove diode assembly.


    Here is a factory Denso diode assembly. Note the gray coating as mentioned in my previous post (as far as I know, Denso is the only one that does this).




    Here is the alternator with all 3 of the common failed parts removed. It takes less than 5 minutes to remove all 3 of these components.


    As for part numbers there are so many remanufacturers of alternators out there I would guess there's dozens of part numbers for these. If you go reman just have them look it up by application. An OEM Denso rebuild is Denso part #210-0272 or #210-0115. Toyota's part number for a Denso rebuild is 27060-72171-84. In my experience the Denso rebuilds are very reliable units (as compared to other rebuilds I have used). Tim

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    Re: Alternator woes

    Name:  TV.dirty.ALT.jpg
Views: 5671
Size:  75.3 KB

    Perhaps this picture is an insult to TV lovers or maybe a testimonial to how resilient these machines are. Nonetheless, this is a picture of my alternator before I cleaned it. Yes, I drive in snow sand and mud. Yes, I have a power steering leak. NO, As far as I know it does not work. I will get it bench tested soon. I am trying to get this all sorted out and back on the road ASAP. Just wanted to share this picture with you.


    I have inspected the three most likely problem areas addressed above. The brushes are intact and look fine. The Diode assembly appears to have intact solder and very similar to the picture presented here. I am unsure about the Voltage Regulator, I suppose a bench test will answer this part. I will keep you updated, with the hope that this info can help expedite future people's problems and questions.
    Last edited by momentum; 03-08-2011 at 04:24 PM.

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    Re: Alternator woes

    UPDATE:

    After cleaning my alternator, I took it to be bench tested. Good news is it tested fine (14.7?). I also tested the battery, which is also fine. So I tried to jump the van and drive it to get a diagnostic done...

    The van will start with a jump start, but if the jumper cables are disconnected, the van immediately dies. Dash light that remain on 1) Charge Engine 2) radiator

    Now what? Am I missing something. Any help would be great...

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    Re: Alternator woes

    Quote Originally Posted by momentum View Post
    UPDATE:

    ...if the jumper cables are disconnected, the van immediately dies...
    That sure sounds like your battery is a problem... or perhaps your terminal connections are very loose. How did you test your battery?

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    Re: Alternator woes

    Quote Originally Posted by Dogfish View Post
    That sure sounds like your battery is a problem... or perhaps your terminal connections are very loose. How did you test your battery?

    Thanks for the reminder Dogfish! I forgot to tighten the Battery terminal connections before jumping it...I tightened the battery and it finally turned over after a couple minutes. I then drove it for a little over a half hour and then turned it off. The van will not start without a jump. I took the battery to a battery shop and it was tested with a hand held battery analyzer. The guy stated it was a little weak, but certainly within specs.

    Back to the forums I suppose.

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    Re: Alternator woes

    That doesn't make sense. Dead batteries cannot be accurately evaluated. If the battery were not dead then the van wouldn't need a jump to start. It sounds to me like you have a dead or junk battery and also have a charge system problem. If your alternator tests good then the next likely thing is the alternator harness. Did you check that as instructed earlier? If not, remove it from the van and test the wires for continuity. Do a visual on the smaller wires where they go inside the round 3 position plug. If there are any questionable connections replace the harness. They are still available through Toyota. Good luck. Tim

    PS: Based on what you've said so far it doesn't sound like a fusible link problem, but at this point I think you should inspect those too.........just in case. Here is a good thread that talks about those in detail: https://www.toyotavantech.com/forum/...le-link-thread

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    Re: Alternator woes

    I'm with Tim. Hand held things don't test batteries. Loads do. Why not just turn on your high beams when stopped. Lights dim? Do they dim down after a minute? A few minutes?
    Yes? Junk battery.

    Bad harness? Very common. My 2wd is okay but my 4wd harness is bypassed like a crazy Christmas tree (hey, I was on the road, I had too, leave me alone!)

    I've never revisited the repair but I should.

    Fusible link? Perhaps so corroded only a perfect battery can push thru enough juice to crank the engine?
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    Re: Alternator woes

    Yeah, I'm a bit old school so I try not to knock things I don't know about. I see these guys at some battery places and shops using these little hand-held load testers and I have serious doubts that these things can do the job. Back when I was getting my training I was taught to test batteries by 1st checking specific gravity with a battery hydrometer or refractometer. This test is to verify "state of charge" and to also verify all cells are within 10% of each other. If the state of charge is less than 75%, then further tests will not be conclusive until the battery is fully charged. If you have one cell that's more than 10% off of the others then the battery is junk. Sometimes batteries with this condition can be brought back using an "equalization charge" (basically a controlled overcharge), but in my experience it usually doesn't work. Even when it does it will only buy you a limited amount of time.

    After battery is fully charged (assuming it can now pass the specific gravity test), it gets a load test. I use a "carbon pile load tester". It's a big box (about 20" X 20" X 6") with a couple of analog gauges on the top and a big black knob in the middle. The proper load for your battery will depend on it's rated capacity. Automotive batteries get 1/2 of rated cold cranking amps and this load is applied for 15 seconds. For an average size van battery that usually works out to about 250A. In order to pass the test the battery must maintain at least 9 3/4 volts for the duration. When load is removed the battery gets 15 seconds of recovery time. Sometime before that 15 seconds runs out voltage should return to at least 12 1/2 volts. If your battery cannot meet these requirements then it's weak or it's shot.

    As for the alternator harness, I've seen this exact failure several times. Here's a picture of my handiwork after having this issue while away from home:


    I did this with materials I had on board my work van while in a parking lot. I drove it like this for several months before replacing my harness. Tim

    PS: There are cheaper carbon pile load testers available (more expensive ones too) than the one I linked to above. Here's a cheap one: http://www.amazon.com/Carbon-Tester-...sin=B00FGCG5DS. But for that price I'd have some doubts as to how well it would work and/or hold up. Tim

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    Re: Alternator woes

    Ya. Good points Tim. Love the alt wiring harness repair. Beauty!
    I guess it goes without saying that my 'lights on' test is a waste of time if the alt harness or alt is not charging the bat.
    I do usually put the bat on my home charger first THEN do an examination under load.
    I don't have the specialized equipment but Toyota thoughtfully equipped the van with thirsty headlamps. A person can get a pretty good idea of battery health while parked in front of the house, splayed in a lawn chair, drinking a beer and watching all four bulbs glowing away for a while. Or 'going away' if the battery is junk.
    Arghhh. Har Har Har. It's a pirate's life for me!

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    Re: Alternator woes

    Yeah, that could work. Assuming that the combined load of all 4 headlights is about 20A (just a guess), a good grp 24 battery could power these for almost 4 hrs before going completely dead. If you do the math (again, assuming the load is 20A) 7 minutes with all 4 headlights would be about equivelent to 15 seconds of a 250A load. So if your battery voltage stays above 10 volts for the duration & returns to 12 1/2 volts within 15 seconds of turning the lights off, then I'd have to say the battery is still okay. Tim

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    Re: Alternator woes

    Today I finally got my new replacement parts from Toyota. I installed a new alternator wiring harness and FL 1.25B fusible link. Glad I got that over with, but the van is still acting up. I took the battery to O'Reilly and the battery was tested with a hand held device and "passed", amps and volts seem fine. I was told the battery was fine, and if it was "bad" the tester would have recommended the battery be tested on another machine...

    The van will not start under its own power! If I do buy a new battery and still the van won't start, what next? I will try the headlight test as well...

    Starter?

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    Re: Alternator woes

    Are you saying it won't crank over? If the battery is charged but the starter does nothing that indicates a starter or starter circuit issue. Here's a thread where that is covered. Tim

    https://www.toyotavantech.com/forum/...witch-question.

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    Re: Alternator woes

    Just wanted to let everyone know the van is back on the road and running like a champ. I replaced the battery, wiring harness and fuseable link. Thanks for the detailed help, I could not have done it with out ya! cheers

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    Re: Alternator woes

    That's awesome! What did you find out regarding the starter circuit?

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    Re: Alternator woes

    Ok folks, I've got an alternator pickle. Mine went, as was expected, due to power steering fluid running amok. I pulled it out and not only were the brushes shot but the fella at the alternator shop said the post running up the the core had only moments of life left in it. No one in this next of the woods had anything to rebuild it themselves and so, for what it would cost me anyway, I ordered a remanufactured job, which I just got in today (Denso reman, looked fine to me).

    But it doesn't fit. The holder for the bottom bolt is somehow too narrow. And now I've got my grease and frustration all over the reman. Am I missing something or did they get me the wrong alternator? The number on the alternator is A8193, which in a google search seemed to align with my van, a 1986 cargo. I double checked my van serial number just to be sure that mine was sold as an 86 (yes, I have a "G" in my code).

    Any help or experience on this one would be wonderful. Tim? Llamavan? I'm tempted to set the darn thing alight... As much as I love it.

  19. #19
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    Re: Alternator woes

    If it looks the same and it's a Denso, then it should fit. The factory alternator mount has a bushing in it that will slide to accommodate alternators that may be a bit smaller. I'm guessing your old alternator was smaller in this mount area and the bushing just needs to be knocked back to a position to accommodate your new alternator. Here's a picture, you can see the bushing in the front end of the mount. Tim


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    Re: Alternator woes

    Tim, you are a gentleman and a scholar. Thanks for the quick response. This was one of my suspicions but the bushing wasn't moving with my initial, um, persuasions. I will attempt further, and perhaps more intelligent, coaxing tomorrow when I get a chance. Thanks for the pic etc. I'll post my news.

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