This procedure was developed from and incorporates text from this excellent rebuilding article by Chris Hamann on the GNTTYPE web site. I owe Chris and GNTTYPE a big thanks for a great source.
Note: several procedures listed below refer to installing an alternator upgrade kit. A 200 amp upgrade kit is available from Turbobuicks.com. If you're just wanting to repair your alternator without a kit, these procedures cover checking the old components as well. The regulator is the one component that's not easily checked without specialized equipment. If everything else checks out OK and the alternator fails to function, you should replace it.
Here's what you should see in your upgrade kit: it includes a new regulator, a new brush assembly, rear bearing, and a new, heavier wound stator.
After you have it marked, remove the four 5/16" socket size bolts that
hold the alternator together. Next, take a hammer and lightly tap
on the front housing ear to pull the alternator apart. This usually
isn't a problem but like anything it can take a while. Set the front
portion (pulley end) aside later for component rebuild.
Now, as we
look into the regulator portion on the alternator, be sure to remove the
two brush springs. They usually are scattered inside the alternator
from removal. Using your 11/32" socket, remove the three bolts holding
the stator in place. Use a hammer to tap on the case while holding
the stator to remove it from the case. Set the stator aside for now.
Next, using your 1/4" socket remove the two bolts that hold the regulator and brush assembly into the case.
Note: The bolt that goes through the brushes is NOT insulated. The one on the other side IS. Be careful, switching these bolts around WILL blow the regulator IMMEDIATELY! Set the regulator/brush assembly aside for later.
Next, using the 7/16" socket, remove the main post from the rectifier
bridge. This just slides right out. Make sure that the insulation
piece is removed from the back side also. Next, using compressed
air blow out the rectifier bridge. Be careful, wear eye protection.
The diodes/rectifier bridge do not have to be removed unless necessary.
Place a paper towel/rag on your bench and set the alternator down
on it. Using your ohmmeter measure the resistance as follows: with
the meter on the 1000k scale, take the negative and place it where
the main post usually goes (the lower half of the rectifier bridge).
Take your positive and place it on 1 of the 3 posts. Go through all
three posts, one at a time and record the readings.
Note: You may have to touch the copper portion below the stud but be sure you are not contacting the 2 halves of the bridge. The resistance should be between 400-800 ohms.
Note: If you are replacing the rectifier bridge/diodes, be sure you get the screws in the right places.
Slide the terminal on the brush assembly over the matching terminal
on the regulator as seen below.
Install the regulator/brush assembly into the alternator, and be
sure to get the INSULATED bolt by the metal clip and the
NON-INSULATED bolt on the brush housing. Tighten down the 5/16" socket
size bolts.
Next, install the Main Battery post and tighten down using your 7/16" socket. Note: Be sure that the insulation piece on the main post isn't cracked and is in place. Sharp eyes will note that I didn't have the insulator in place in the pictures below; I had to take it back apart and put it in. Try and avoid that...
Using the ohmmeter, check the stator now. You should have continuity
through all three posts of the stator and NOTHING to ground.
Next, install the stator. Tighten down the 3 11/32" socket size bolts. Note: Be SURE that the stator wires ARE NOT contacting ANY other part of the rectifier assembly BUT the stud and copper pieces. Be really sure of this. Set the case aside.
Pick up the pulley end of the alternator now. Using your impact and
your 15/16" socket, remove the nut. The pulley and fan should slide
right off. Note: there are spacer washers between the fan and bearing
(smaller); fan and pulley (larger). Be sure to get these in the
CORRECT places. Otherwise your fan might be sticking out 1/4"
of an inch more than it should.
You will need to do it if you need to replace the front bearing (buy separately), to sand the commutators, or to polish the case, etc.
Now, you may need a press or a gear puller to press the rotor off of the housing. The pictures show a gear puller being used. Be sure to get the spacer off of the rotor shaft. If you don't have access to one a BRASS hammer will do.
Once you have the
rotor removed from the housing, using your 5/16" socket, remove the
three retaining bolts that hold the retainer in. Now, using your
punch, punch the bearing out of the housing. Oil the new bearing
and using a hammer tap it into the housing making sure it's flush.
Install the retainer and tighten the three 5/16 socket size bolts.
Next, using an ohmmeter, make sure you have continuity through
both slip rings (Where the brushes ride) and NOTHING to ground.
Place the rotor in a vise horizontally. Using a punch, remove the
small bearing on the shaft (Yes, there is a special puller for this,
but this works just fine!). Next, place the rotor in the vise
vertically. Using 80-120 emery cloth, sand the commutator
(the copper colored discs where the brushes ride). Now oil the
shaft and install
the bearing using a hammer. Make sure it's flush with the end of
the shaft. The picture below shows it just before driving it on
and flush.
Install the spacer onto the rotor shaft and oil
the shaft. Install the rotor into the housing; you may have
to tap it until it stops. Next, install the small spacer, fan,
larger spacer, pulley, flat washer and then the nut. Tighten the
nut with an impact.
Place the alternator on its' pulley.
Be sure to lube the small bearing and place the case over the the
rotor. Line up your scribe mark and using a hammer, tap the
housing on until it stops. Install the four 5/16" socket size bolts and
tighten down. Finally, remove the mechanics wire that holds the
brushes in.
You're done! You now have a gorgeous, upgraded alternator.
Candy canes are optional and may be hard to install.
