Alternator Diagnosis, Removal, Rebuild, and Installation Guide

[IndestructibleYaris]

DIAGNOSIS

Usually the battery light, w/ or w/o PS light, ABS, BRAKE light all coming on at once or the battery light flickering means the alternator usually is going bad. Some of these symptoms could also be corroded or loose wiring/main cables.

The yaris alternator is a very well built and user-servicable unit, but it will not last forever. Mine became faulty at 345,000 miles with a blown diode, and the brushes were almost completely worn to nothing.

The battery light is triggered by low voltage, excessive AC voltage/current, or an open circuit in the excitor circuit.

Faulty Rectifier/diode pack/tridiode: Battery dies overnight, flickering battery light, burning smell. Has continuity from naked alternator positive post to ground and continuity from ground to positive alternator post. Check with diode setting on multimeter(arrow pointing against a wall symbol). You must remove battery wire from alternator for this test.

Faulty Voltage Regulator: Overvoltage. Burning smell. Odd alternator output (weak/dead/too strong). Battery holds voltage overnight.

Faulty Brushes: Battery light illuminated or flickering. Battery holds voltage overnight.

I reccomend ordering parts from China on ebay or amazon for the cost savings. I have not had an issue with chinese parts. The only downside is waiting for the parts to arrive. If you're strapped for time and don't have a spare method of transportation, this job isn't for you.

TOOLS
10mm socket or wrench
12mm Deep socket
14mm Deep and Shallow socket
Pick tool and pliers (for connectors)


STEPS

0. Unplug connectors by the alternator, Remove battery negative (10mm), remove the battery wire on the alternator positive post if not done already (10mm), oil it and take your time as the plastic is brittle, and unclip wiring hold downs for extra room and less frustration.

1. Remove alternator adjustment pinch bolt and slotted bracket from engine block. (12mm heads)

2. Remove AC bracket bolt to the left of the alternator pivot bolt, or just slide the bracket along the AC line towards you as far as you can.

3. Remove alternator pinch bolt. (14mm head)
This step was such a pain. I had to keep switching between a deep socket, shallow, and then a wrench, all while the socket slips off and is rounding over the head of the bolt.

4. OIL the bottom alternator ears thoroughly. It is still pinched to the bracket on the car by corrosion. Mine did not come easily at all. Gently lift alternator, taking care not to crush any connectors or wiring

INSTALLATION

Install is reverse of removal, with some added steps to make your life easier if you have a file and a metric tap and die set.

The threads in the engine block for the slotted bracket were very pristine and clean on my yaris. Yours may vary.

1. Tap lower alternator hinge nut
https://ibb.co/F3yP7b7

2. Use die over hinge bolt

3. Use die and tap through slotted bracket bolt, mounting stud, and top alternator ear

4. File approximately 10 strokes on the inner face of the lower alternator hinge nut, just enough to get all the rust off. This restores some clearance so the alternator will slide in a little easier

5. Use antisieze on all the threads when installing. A small lick is enough. My alternator battery post became stripped from a seized nut and the hinge bolt needed a wrench the whole way coming out. This is why anti seize is recommended.

6. Grease electrical connectors to prevent oxidation and dirt intrusion.

REBUILDING

I highly recommend rebuilding as a cost effective solution. This will take time with waiting for parts, but in my opinion is worth the effort, as you'll never have to buy an expensive, garbage "remanufactured" alternator again. Usually they won't pay any mind to the bearings or slip rings, and this may lead to a very premature failure, not to mention the stripped or overtorqued fasteners that you'll never get out if need be.

TOOLS
10mm deep socket
8mm deep socket
5.5mm socket (odd size, home depot sells them individually for 2$ each, or look for a 7/32 which is almost exactly the same size)
JIS screwdriver
Vise grips
Hammer
Bearing grease
Brake clean or any solvent
Pick tool
Flathead screwdriver
Spare m4 screws

PART NUMBERS

Brushes with holder: 1639-8213
Ebay title example from AMF Industrial: New Alternator Brush Holder for Sonata 2006 2007 Santa fe Sedona 130AMP

Rectifier (upgraded amp rating with extra diodes):
Couldn't find a part number but I just referenced the measurements on the image
https://ibb.co/BsVS19d
Cross reference
FIT FOR
2007-2009 Lexus RX350 V6 3.5L
2005-2014 Toyota Avalon V6 3.5L
2007-2014 Toyota Camry V6 3.5L
2009-2012 Toyota Venza V6 3.5L
2008-2013 Toyota Highlander V6 3.5L
2009-2012 Toyota RAV4 V6 3.5L

Use youtube as a reference. This is a denso alternator and is referred to as such. Search "Denso alternator rebuild" and reference Mike Lauer of rebuilder in a box. Great videos, but his rebuild kits are a little pricey.

For supplementation of his methods, look at other videos "toyota alternator rebuild". These alternators are also shared with Hondas, Hyundai, and many other cars too, with the only differences being the overall size, mounting, and the connector and stud placement. The internal construction is always the same.

Use a JIS screwdriver on this alternator, or you will strip out small screws, especially on the bearing retainer. If you have to drill any screws out they're m4 screws. Use a 5.5mm or 7/32 instead of the screwdriver whenever possible. Vise grips may be able to save you on the exposed voltage regulator but any other stripped screws need a 1/8" drill and a replacement screw.

The most intensive thing about rebuilding an alternator is the slip rings and the bearings. Both of mine were good but i wanted to breathe new life into the bearings, as every time I've done this (even on seized fan bearings) it allows the bearings to be reused and go on for decades. I wouldn't do this on any bearing that has play, as an alternator has very small tolerances that must remain good with healthy bearings.

The bearings can be exposed using just hand tools and a block of wood. I used a press because it's easier and a lot better for the bearings, and there's a much smaller chance that you'll mess something up.

The one bearing on the side of the slip rings has a friction fit collar that can be pried off with a screwdriver and reused. Reinstall this collar with a 12mm socket and light taps from a hammer. There is also a wavy washer that must be kept track of.

With the one bearing retainer removed and the other bearing on the shaft, remove the shields from the bearings with a pick. Scoop out as much dirt and old grease out as possible. Then clean the bearings with brake clean, spinning the bearings to clean as deep as possible. Pump grease onto the unshielded bearing. Reinstall shield, pushing excess grease through the bearing and spin bearing to verify the drag of grease reached the balls.

Once again, if all this is too much just send it to me and I'll get you done. It's therapeutic to me. If you're on a time crunch you can always buy a garbo alternator just to get you by while your alternator gets rebuilt, but i wouldn't trust anything from a big chain parts store.

I hope this helps anyone else on a tight budget or who just takes pride and has peace of mind with a well-loved machine. Thanks for reading

[remcafee]

to avoid rounding off the lower alternator bolt, i use a 0 degree offset wrench, or if you hsve a low profile ratchet that clears the water pump pulley that too, it drives me nuts everytime i see one of these come in at work with the alternator bolt rounded to hell

[IndestructibleYaris]

Originally Posted by remcafee

drives me nuts everytime i see one of these come in at work with the alternator bolt rounded to hell

I welded a huge nut over the old bolt and now it's a 16 or 17mm head! Somehow had room for a socket and both ends of a wrench. It'll never round over again haha