Toyota alternator fix on the cheap

When your alternator light comes on, you probably don’t have to buy a remanufactured alternator for $120.  90% of the time the problem is the brushes are worn out, and can be fixed for $3!

Brushes simply wear out over time, and are meant to be replaced.  When you pay $120 at AutoZone for a reman alternator, you’re basically paying for the alternator to be shipped to their alternator rebuilder partner, taken apart, cleaned, brushes replaced, possibly replace other parts that go bad less often like bearings and voltage regulator, and shipped back.  Plus a mark-up, of course!

Sometimes brushes wear out faster than normal when the bearings are bad.  If you find this procedure fixes your alternator only for a short time, you may need to replace the bearings next time.

Symptoms

Your alternator light comes on.  When mine first came on, it would turn off above 2500 RPMs.  When I pulled the alternator and took it to AutoZone to test, their machine spun it so fast that it tested good!  That was good, though, because it told me the voltage regulator was fine.

Tools

  • The tools required to remove and replace the alternator; for my ‘95 4Runner:
    • 10mm, 12mm and 14mm sockets, wrench and extension
    • pry bar, or something else to apply tension to belt
    • 1/16″ music wire, if your alternator connector tab is broken
    • a belt tension gauge, optional
  • New brushes:  part FAX88 from AutoZone toy-alternator 003.jpg
  • Tools to disassemble the alternator:
    • 8mm and 10mm nut drivers or sockets
    • philips screwdriver
  • Soldering iron and solder
  • Wire nippers

Remove the alternator

  • First, disconnect the battery!!! If you short the main alternator cable to ground while working, you’ll have a lot of extra trouble replacing the fusible link.  Ask me how I know!  toy-alternator 039.jpg
  • On my 4Runner, to make space to pull the alternator out, it’s easiest to remove the small air hoses where they connect to the air box in front of the alternator.
  • Loosen and remove the top and bottom alternator bolts.  The alternator will be free.  You disconnected the battery, right???
  • Remove the cap from the alternator main wire and unbolt the wire.  toy-alternator 028.jpg   toy-alternator 027.jpg
  • On the other alternator connector, push in the tab and pull the connector out.  If the tab breaks from heat and old age, don’t chew up the connector with pliers trying to get it out!  Just stick a piece of music wire (or something long, thin and stiff) into the hole in the connector and push it in as though it were the original tab.  Note the hole at the bottom below the middle wire:  toy-alternator 023.jpg  Insert a wire like this and press in the directon of the wire:  toy-alternator 024.jpg
  • On the 4Runner, the alternator should come out the front.

Repairing the alternator

Before you start, you should take the alternator to AutoZone for testing (and buying the new brushes).  They’ll test it for free, and tell you several things about it.  If the voltage regulator tests come back bad, you may need to replace that, too.  You should be able to buy that from an online or local alternator repair shop, but I’ve never done this.

  • Start heating up your soldering iron.
  • Remove the plastic insulator around the main wire terminal with a 10mm nut driver.    toy-alternator 021.jpg
  • Remove three 8mm nuts and the rear cover from the alternator.    toy-alternator 020.jpg   toy-alternator 019.jpg
  • Remove two screws that hold in the brush assembly with a philips screwdriver.    toy-alternator 017.jpg   toy-alternator 004.jpg  You can see the problem here, one brush has been worn down.    toy-alternator 010.jpg
  • Desolder ONE of the old brushes.  Leave the other in place so you know what position to solder the new brush into.  Don’t lose the spring.   toy-alternator 006.jpg
  • Install the new brush.  Pull it into the housing so that the brush-side end of the cable is about level with the other brush, maybe 1/16″ below the edge of the housing.    toy-alternator 009.jpg   toy-alternator 010.jpg I found it handy to wrap the lead around the assembly’s mount to hold the brush in the right place while soldering.    toy-alternator 007.jpg
  • Solder in place, then trim the lead so that none sticks out.    toy-alternator 008.jpg
  • Now do the other side.   toy-alternator 014.jpg  toy-alternator 013.jpg   toy-alternator 015.jpg
  • Put the brush assembly back together.
  • Install the brush assembly with the two screws.
  • Install the rear cover.
  • Install the main wire terminal insulator.
  • Done!  You just saved $120 by spending $3!

Replace the alternator

Replacement is the reverse of assembly.  One trick:

  • Use a pry bar between the alternator bracket and alternator to put tension on the belt while you tighten the lower nut.  toy-alternator 036.jpg  toy-alternator 034.jpg Pushing pretty hard on it easily got me over 80 lbs. tension; the Toyota FSM says a used belt should be at 100 +/- 20 lbs. (160 +/- 20 for new belt run <5 minutes).  toy-alternator 032.jpg

One Response to “Toyota alternator fix on the cheap”

  1. Jeffrey Bridge Says:

    What’s up! I haven’t heard from you in a decade. Let’s catch up sometime this decade.

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