AE92 MAP 4AGZE Alternator Rebuild

[inertia]

Posted this on twincam, thought it might help some people here also
twincam link: http://www.twincam.info/index.php?sh...=0#entry355758

Well I've been noticing that, over the past month or so, driving with my headlights, heater and stereo on is causing the voltage to slowly but surely drop to the point where if I indicate the dashlights dim, all other warning lights, the opposite indicator, the highbeam indicator and the rear window demister indicator all light up in sequence with the indicator flashing...

So I've checked the battery and it seems fine, there are no leaks in the system and the electrical connections appear to be clean... time to look at the alternator/regulator. Following the Haynes manual and checking the voltage with the car off, then engine on, then engine and accessories on confirmed that the voltage was dropping the more the system was loaded up and holding the revs higher did not up the voltage. It still sat below 12v and dropped to 11.4v after a while.

With a little bit of cursing because I seemed to have either lost or loaned out my offset ring spanner set... I managed to get the idler pulley off and then unbolted the alternator.

So here it is, the AE92 MAP 4AGZE Denso unit.

Part Numbers
Toyota: 27060-16131
Denso: 100211-33(0 or 8 or 9)1
Stamped: 12K



Time to pull the back cover off and have a look at the bushes, regulator and rectifier... the rear cover is held on by a 3 little 8mm nuts and then you must remove the two 10mm nuts off the side terminal B I believe) that hold the insulator and the cable on. The rear cover then jiggles off to expose the back, which as you can see sports a cracked and filthy rectifier, a filthy regulator and the brush holder under its rubber cover.



I will warn you all now, these little phillips head screws are so damned rusty/corroded that they are very brittle and utmost care must be taken to remove them, I had to belt a screw drive into the rust and luckily they gripped and came out, one of them got halfway then refused to budge, multigrips were used to remove it fully. I suppose you could use innox or WD40 etc to soak in before attempting to remove them.

All components off the back.



As you can see the insides are quite dirty, as you would expect after years of driving, and one year with no bottom plastic covers on... the alternator on the gze is quite low so is possibly more prone to picking up road grime than a unit that is mounted high in the engine bay...

Slip rings appear to be in reasonable condition, will be confirming this once I pull the alternator apart fully, they may just need to be hit with some sandpaper or a hit with the dremel..



I google'd a bit on rebuilding the alternator, however have received most advice from Old Corollas on toymods (thanks Stewart!)
I also have the Autoshop101 technical articles printed, the relevant article for diagnosing the alternator is available here:

http://www.autoshop101.com/forms/h8.pdf

I followed this document and everything appears ok except the rectifier, the diode P terminal closest to the B terminal is not giving the expected resistance behavior.

After checking my local Autobarn, Repco and Bursons I rang Bill at Autopro in Campbellfield (top bloke) who directed me to a company called Ashdown Ingram, they deal in DENSO parts etc.

This morning I went in there armed with all the part numbers off the plaque on my alternator (listed above). The dude there was very helpful, I believe he used the DENSO number (the middle one). The total cost for new bearings, regulator, rectifier and brush holder with brushes was $149.

Here is some new versus old pics. The new parts all appear to be distributed by OEX Rotating Electrical Components (PARTS FACTORY) in Brisbane.

Regulator DENSO part# 126000-0700. This is an actual DENSO part, made in Japan.
OEX part# RGX2018 Regulator N/Denso 12v TOYOTA.


Rectifier TRANSPO part# INR720 324D U.S REC NIP 98mm. This is assembled in USA.
OEX part# RFX2003 Rectifier LGE N/Denso.


Brush Holder UNIPOINT part# UNI0611631. NFI where this is made.
OEX part# 13-70300 RPL N/D Brush Holder.


Bearings (two of them).
NSK part# B15-69T12DDWNCXCM WR3M 511. This is made in Japan.
OEX part# BEX2003.

WTW part# 6302RS. This is made in Japan. WRONG PART!!!
OEX part# BEX2007.

The bearing it is supposed to replace is unavailable locally

Bearing Wholesalers Part# =DDG15462RDDCM.
Toyota Part# 27310B
ID = 15mm
OD = 26mm
Width = 46mm

Toyota can get it from Japan and it costs about $80.



Screws:
Most of these are 4mm. They vary in length so you can probably get a pack of 35mm and cut them down.

Toyota part#'s for the screws and other bits:
4x 90099-00170 = Front Bearing Retainer plate screws
7x 90099-00959 = Rectifier Terminals & Brush Holder/Regulator
4x27389063020 = Rubber insulators for Stator Wires.
7x 90099-05172 = Nuts to hold back cover on and the two halves of the alternator together
1x 27387-70170 = Terminal Insulator

That's it for now, basically I'll be pulling the alternator apart completely, giving everything a good degrease and clean and letting it dry for a few days, will also hit the casing with the dremel to remove the grime, then the re-assembly will take place.

[inertia]

Ok,

First off thanks to Jezza(rallystanza) for some genious work with a steering wheel puller and some spare bolts to press the rotor out of the rear housing/bearing and for knocking the front bearing out .


Started off by giving the various bits and pieces another round of degreasing and a wipe down with some scourers... tried the dremel with a SS brush but it was not the best at the job.

Here's a few before pics of the dirty bits.

[inertia]

Here's the old rear stuffed rear bearing and the little bearing retainer that is well and truly screwed from smacking the bearing out of the casing... I used a socked on the underside of the rear casing to support it whilst hitting the bearing out from the outside with a long socket extension and a hammerski.



Then Kooka decided to lob over my shoulder to see what I was doing, so I got mum out to give it some mince meat .



Currawong didn't want to miss out on a feed so down it hopped too...



So after degreasing and scouring I took the bits inside and gave em a good session with the hairdryer and under the heat lights in the bathroom .



Note how I have sanded the rotor shafts so that they'll go into the bearing easier... I also sanded inside where the bearings sit in each of the halves of the casing...



Here is the wrong WTW bearing that Ashdown supplied... for the front


Here is the bearing it is supposed to replace!

[inertia]

I lubed up the outer of the bearings to help them go in... I also heated up the casing with a heatgun for a good 15mins before knocking the bearings in gently with the help of a long extension and appropriately sized socket (OD of the bearing so it contacts the metal and not the seal..)

Heatgun FTW!


Front Bearing In.


I used an appropriate Outer Diameter socket and extension to help knock these in...


New Front Bearing Retainer installed $7


Rear Bearing In


I then proceeded to f##k up the installation of the rotor into the rear housing by killing my newly purchased rear bearing retainer by not making sure he was over the shaft before belting it in with a hammer... this then took 15mins to pull the rotor out and then straighten up the retainer with a pair of pliers and the use of an appropriate sized socket and hammerski...

Rear bearing retainer McFucked then McFixed $5


But all was well and it went in fine the next time!

[inertia]

The front just slid in easy as, no hammering needed and I then bolted the two halves together. Care is taken the pre-insert the stator wires through their holes before doing this!! Their rubber insulators were re-installed (new ones are $9 each... no thanks!)




Next I installed the electrics... I bought new small screws from toyota at $1ea... needed 7 of em...


When putting in the brush pack you need to use a small screw driver or something to depress the brushes into the pack and then guide them into the slip ring grooves...

Rear cover is then put back on...



It is smooth as silk now and very tight .

Final pics to come once I install it on the car and test the voltages... unless it doesn't work and then you might see it thrown out of a moving vehicle at 100kmh!!!

[BradW]

Very good write up. The only suggestion I would make would have been to have the slip rings on the rotor machined flat. Any auto elec would be able to do this for you or if you have access to a lathe you could do it yourself. Machining the slip rings will help your new brushes last longer and help prevent them from breaking due to them running on an uneven surface.

[inertia]

Thanks mate, will see how they go, I did give them a light sanding but that's about it.

I got the alternator on the car tonight and drove for about 45minutes, no more major voltage drop, was running fine with the heater on full blower, stereo and headlights.

Idling with heater on full, high beams and stereo it was rock solid at 14.56v.

My battery is over 3 years old, I might replace just to have confidence in the electrics for the next few years...

[JBs]

Awesome write up I will be bookmarking this so I can overhaul my spare Alternator in the near future.
Cheers

+Rep

Edit: Must spread love.

[Rallystanza]

Good stuff there Fergus.

Will definately help when i rebuilt mine too.

Rep for j00

[inertia]

Cheers Jez, least we'll know how now
And where to get the bits cheap...

Good thing about doing this myself is that I know every component has been replaced, save the front bearing / rotor / stator and casing, which tested fine.

[Vios-GT_07]

+ rep

thread bookmarked.. i'll do this just to try it, when the alternator decides to give way.. there's signs my alternator and distributor are on their way out

[inertia]

This morning on the way to work the voltage indicator in my SX Cluster dropped to below half way and all the warning lights came on whenever I indicated!!!

Guess there's more gremlins than the alternator, perhaps I do need to replace this 3+ year old battery as well... hope that is all as the alternator definately had problems according to the alternator test document linked in my first thread.. .