SkOrPn

Hello everyone, my name is Rod and Im happy to meet you all.

I have been a Lexus owner for approximately 5 years now, but amazingly my car has never left my family. My father purchased this car in 94 and drove it everyday to work until roughly 2001 or so (then he purchased a 2001 Lexus and also a BMW lol), then my brother purchased it from him and he was extremely good with its maintenance, although drove it hard and was forced to put in a new Tranny less than a year before I got it. Then in summer 2006 he got the urge to buy a new Altima, and just days before his new car urge I blew up my Dodge spirits V6, lol, so luckily with 180k and in fairly descent shape I got the car for only $2k. I love her but Im not doing so good with maintenance lately I admit. I am discovering that this car has one hell of a will power to live and makes me want to help her live longer. Recently, I lost my job due to health reasons and been living on a fixed and very low income and all of a sudden all the things that need fixing are happening during this poor phase of mine, it figures. Driver door stopped working but that was fixed with new plastic clips, a loud popping sound in the right front suspension when I accelerate or decelerate, but even worse is my Alternator has finally givin out at 230k miles and well I can not afford to replace it, so I purchased a new regulator and brush holder from the start shop here for pretty cheap, much cheaper than I expected it to cost, and much much cheaper then a new reman alt even from the Zone.

BUT, my question is, although this alternator looks like a blind man could repair (yes it looks like I can repair this thing in my sleep), I am not sure why the shop only sold me a Regulator and Brushes. Is it because the bearings need special tools and they just assumed I do not have them? And why didnt he sell me new diodes? Are the diodes part of the regulator or brush assembly, and therefor not needed seperately? The parts he sold me look identical to mine and also look high quality in appearance. Although the bearings dont make any sound and feel really good when turning the pulley, I can only assume that bearing replacement should be left to the pros because of special tools, presses etc??? Is that why he only gave me a reg and brushes? He specifically told me that's all I would need to get it going right away. Is he correct?

Autozone and tripple AAA (don't ask) tested my alternator and said my Diodes are bad, but the alternator was putting out 14.5v. When I step on the brakes or turn on the radio, the lights dim even with a new 750 CCA battery. After a full charge, it only takes a few weeks/months for my battery to be dead again, and I have to remove it and put it on my charger again. This is my 3rd battery in the last 5 years, but the last 2, which were much nicer than what I got from my brother only lasted a year before going bad. So I assume the Alt is killing them with AC current? This last battery is only a few months old now but has already gone dead and I had to charge it again. I just dont want to kill this battery like I did the last one.

Don't all this mean I need new diodes? And if so, where are they located? In the regulator OR inside the Alternator itself? And can they be purchased online somewhere, or do I need to call the start shop back and tell him I need new diodes also?

1994 ES300
The tag on the alt says:
Toyota 27060-20010
ND 101211-5620 (not sure if that last zero belongs there or not).

I plan on pulling the alt immediately after posting this, cleaning it up with CRC Lectra-Motive Alternator cleaner and a brush, but will not start the actual repair until I get some advice from you Lexus experts

Thanks for any knowledge/tips you are willing to share. I appreciate it....

Rod


EDIT:

Ok, Alternator is out. Oh boy, I almost can't believe how easy that was to pull. The only problem I had was my lower back getting pissed off after just a few minutes, haha. 15 minutes for both the Battery and Alternator removal, washing up of my hands and putting away the tools. Thank you Lexus...

I will wait for replies before cleaning it up and repairing it. Thanks

LeX2K

I'm not sure exactly what you're asking exactly, but I doubt the diodes are part of a rebuild kit.

All alternators have diodes, when they burn out they most likely short out and basically turn into a solid wire in terms of conduction. When this happens, the alternator does not output enough current. You can test the diodes with a multi-meter, and they can be replaced by using a high wattage soldering iron. But when replacing these diodes, care has to be taken or too much heat will damage or destroy them.

A simple alternator test is to turn on all the accessories in the car that you can, lights, rear defroster, fan, etc. everything. Then test the battery voltage. At idle, it should be about 12.6 volts and above. Rev the engine, and you should see 13.0+ volts. A good alternator will at least be able to keep the battery from draining even with everything on. If you don't see this, the alternator is not doing its job. An alternator can and will put out 14 volts with a bad diode, it just won't output the full current it's rated at.

edit - to answer your question of where to buy the diodes, any place that rebuilds starters, alternators etc. would have them. They might even be able to test and repair your unit for a reasonable cost. Otherwise, another good source is a salvage yard, you can dismantle the alternator and just take the diode plate. The bearings are typically pressed on, you need at least a good vice and some sockets etc. to press them on and off, although the job can be difficult. Keep in mind that many bearings can be repacked, just pry off the cover/seal, clean, and repack with grease.

SkOrPn

Most excellent reply. Yes I have been researching and apparently a new rectifier will cost me $50, so I guess I may be SOL. I have expensive soldering equipment that will do the job if I knew what to do. Looks like I should have sold something on ebay to try and make the extra money I needed to just get a reman from the zone. The new rectifier is $50+ S&H it looks like and instead of 8-40 ampere diodes, it contains 8-50 ampere diodes (Not exactly sure what that means to me, but it looks like a direct bolt-in replacement). The only difference is mine is Part# INR402P and the replacement is INR402.

So, just great, looks like trying to save money will cost me in the long run. No wonder they say its better to just buy a reman. The diode trio rectifier thingy looks aweful and I seriously doubt its any good. A few of the diodes almost look like the have exploded/cracked open from heat etc. The brushes didnt even push out at all, lol, just stayed where they were haha. I guess I better do some more reading and see if I can use my Fluke meter to test these diodes myself. I have two soldering irons, a cheap 40 watt from the shack and a nice weller 60 watt that adjusts up to 850f. I have all kinds of new tips ready to be put into service if need be.

I will call around to a few U-Pull Its and see if I can find an alt to take parts off of. Also, I think I will just go back to the Start Shop and bring my rectifier with me and ask him to tell me if its any good and if he has one that wont cost me my arm and leg... lol, Thanks again...

Rod

EEngineer

what an essay....too tired to ready everything, but it seems either ur alternator is going beserk and charging the batteries until they explode, or u have a bad ground somehow.

LeX2K

If it was me, I would replace the entire unit with one from a salvage yard. Even if you repair the diode assembly, there could be something else wrong with the alternator. And yes check for corroded or bad ground lugs.

BTW, a bad rectifier makes it really hard on a battery, they die quickly.

BK4293

If you do go with a remanufactured alt on a budget, go to Pepboys. They will sell you the Bosch altenator, price match Autozone and give you another 5% off after price matching....

Oh yeah, I'm just that cheap, and you're right, I was amazed how fast and easy the altenator is to change.

SkOrPn

Yeah I used to be the commercial manager at Pepboys for 6 years in Santa Fe NM, so Im familiar with their practices, but rusty knowing what brands they sell (along with very forgetful). Bosch huh, and I take it its better than what the zone sells as a brand? hmm interesting.

Well I just finished rebuilding it myself and I think it will work just fine. Only need enough time out of it to help me find work, then once Im back on my feet Im dropping a professionally built 130amp into her just for the hell of it. On a side note, the Start Shop tech said I should keep my old Toyota supplied regulator as a backup as he believes its probably a better one than the one I got from the bay.

Yeah, still thinking to myself what a nice spot for an alternator as I got myself a lower back that does not like it when I am hunched over for extended periods. It made sense though considering the alternator bracket is used for the belt tension adjustment, which needs to be located conveniently I would think.

Thanks for the info guys, Im off now to get this thing tested. Wish me luck please. Oh and by the way, my Rectifier was not only bad it was super bad and the start shop said its been like that a long time, but thankfully he sold me one that looked new (claimed it was used) for only $10 (online shops wanted $50 for a new one). It was just more convenient for me to charge the battery then to get the alternator fixed (lets hope she feels better after this), lol... I need to work on that lazy side of me a bit more.

Best Regards
Rod

SkOrPn

UPDATE:

Well, looks like I goofed up trying to rebuild my own Alternator. I thought it was a simple matter of just throwing on a new regulator and brushes, or at least the brushes. But apparently not only was my brushes bad, so was the Bridge Rectifier/Diodes. After putting it all together I had two different Autozones tell me it was bad both with different results. The Start Shop tested it and they gave me accurate results, their method said that everything was working up to par except for the Stator/Windings and was only putting out 12.5 V at full bench load. And upon closer inspection you can see many of the windings burnt to a crisp. So a total of $55 was spent on parts so far and Im still lacking one of the most important parts, the Stator. On the car she turns out 14.5 V until an accessory is turned on, then she drops to 13.2, then when a second accessory is turned on it drops further to 12.5 and then seems to remain at the 12.3 - 12.5 v range. I have already cleaned it up and it looks and feels like brand new, so now if I can pull a stator from a U-Pull IT junk yard, and or buy a used one from a start shop type business for cheap, I might be able to sell it as a like-new-rebuilt alternator for the same price I put into it. Well see I guess.

In the meantime a new reman 130 AMP is on the way. lol

SkOrPn

UPDATE 2:

Well Ok, I just finished installing the shiny new 130 amp Alternator and it is doing the exact same thing as the old 80 amp Alternator. My current meter results are:

Fresh charge on new battery. When connected and car off battery voltage is 13.00v. When I turn on the car voltage rises to 13.63 (old alt was 14.5), when I rev car to 2000 rpm there is not much change, maybe 13.8 tops, when I turn on accessories (headlights, AC, Fans, Defroster) voltage drops to 12.4v and stabilizes there. Revving to 2000 rpm brings voltage back up to 13.6 to 13.7 area, and then idling brings voltage back to 12.4 and stabilizes. I was told I needed at least 13.8 to maintain a battery charge. Is this a symptom of a weak Regulator maybe?

Now, my old original Toyota alternator would put out 14.5v when car was idling, but then drop to 12.0v when ANY accessory came on. I now have two Alternators and neither are giving me the Voltage I need to maintain a proper charge when any accessory comes on. The old Alt also has a new bridge rectifier, new brushes and a new regulator. The ONLY thing currently bad on my OLD toyota 80 amp alt is the stator windings are toast. The new alternator is a 130 AMP model and everything looks brand new and shiney, even the windings look new. So, should I try using my old toyota regulator (the one that put out 14.5 v) or maybe even the new reg that is still in my old alternator? with TWO new bridge rectifiers, 2 new brush assemblies and two known to be good Regulators, I now feel that I should be able to get this working unless something else is wrong with the car.

Is there anything else I should check? Im thinking of replacing the battery cables, but not sure yet since they look good in appearance. Any tips would be appreciated in the way of trouble shooting. Taking new alternator to the Start Shop to have it tested in the meantime.

EDIT: Well, the Alternator supplier just emailed me back and said those voltages are perfectly OK, because I have a 130 AMP Alternator. LOL, maybe I don't know much about this stuff, but it seems to me that Voltage is more important when trying to push current into a battery. If the supplied V is the same and the V already present in the battery than there is no electrical pressure to keep the battery topped off? Or am I wrong? He has not replied yet, but Im curious if I should try my old toyota regulator since it was supplying 14.5 v?

lastguy

what a pity no photo posted, interesting DIY.
the large the diode, the less drop at high current. I don't know whey they use 8 diodes, a bridge needs four, and parallel is no good.

SkOrPn

This thread was never meant to be a DIY. I was simply asking about rebuild parts and if I needed diodes for rebuilding my old Alt. However, this problem was solved by a new reman 130amp Alternator that is working just fine since last August. Even though it does not seem to put out proper voltage the car has not had a single problem starting since and the battery stays fully charged. The local Start Shop tested it and said its putting out about 125AMP at full load and said it benched just fine. So, this thread is solved.