I read all the posts on 100 Amp alternators and didn't see what I wanted to see... how to get this done on the cheap, with no problems. All the $40,000+ cars have them, but I wonder: do those cars have windows that roll up and down fast and windshield wipers that zip across the windshield with ease when you really need them to? I'm doing a no excuses 1973 Pantera which I just got, so here's what I did:
NAPA has a 100 Amp Motorcraft alternator for about $150.00 including core charge. It was in stock, so I bought it. It's about 6" diameter and about 1" thicker than the stock alternator, so I knew it was going to be a tight squeeze. It ended up taking me a full weekend plus Monday evening to get it done, but this will save you some time.
1) while you're still clean and not sweating, take the NAPA Alternator (or 100 AMP Motorcraft wherever you get it from) apart. That's the 3/8" or 7/16" four bolts holding it together. I mean, you can leave the pulley on for now, but it's gonna come off later to put the smaller fan from the original alternator on, so lets focus on this 1st. Pull the 2 halves apart like an Oreo cookie and the alternator brushes will pop out, so do this under good light, I recommend the kitchen counter or table. Pull it apart and account for those little sptings, which should still be around (1" +/-).
2) My rebuilt Alternator showed rust on the windings and armature, and rust is FeO2, an insulator, I want to see Fe--, so electrons can pass through. Get your sand paper and sand the Armature (the thing which spins around with the rust on it), clean this thing, cause my NAPA box said "tested at 70 Amps" and I want 100 Amps, cause that's what it's sopposed to do, can do and will do, and if I'm gonna take this project down to the component level, it's gonna be right. Next lightly sandpaper the inside of the altenator casing to remove the rust there (this thing was rebuilt, why didn't they do this??? You want thing done right....) Next, get a mild acid, I used vinegar, and vipe down these areas you just sabndpapered...now they look shiny an will pass the amount of current thru that they were designed to.
3) Why did you just take apart the alternator and cause all this worry about the Warranty??? Because, you going to reassemble it a little differently. This is a major point. Put it back together with the two halves turned 180 degrees from how it was originally. See, when you go to install it, you will see what the problem was: the leads BAT, STA, FLD, GRD are way too close to the engine block, could short out, can not be reached to install, and the wires are too short to reach all that way, so this will make these lead wires easier to install, get less heat exposure and make them easy to install.
4) Reassembly. Been worrying about those springs on the brushes? Take that little ceramic device off and out of the alternator housing. My Ground brush was on the kitchen counter without a map to get home.... You can see it is a ground and so goes against the alternator housing, so put the circular part of the brush, the metal part the screw goes through against the housing of the alternator and the screw will hold it in place against the alternator housing in a minute. (Brush is a graphite rectangle about 1/3" long with a wire attached to it and a circular fitting at the other end) Go get a paper clip and straighten it out, or use a toothpick for this next step. Push the brushes back into the little ceramic housing and push your paperclip through the little hole to hold the brushes recessed against the spring tension while reassebling this gadget. Look down into the half of the alternator housing that does not have the pulley, where the brushes came from, and you'll see a tiny little hole that the other end of the paper clip is going to go into. So take this little ceramic package with the brushes held retained back against the springs and lower iit into the tiny little hole just offset from the center bushing. Remember to turn the halves so that the electrical leads are 180 degrees from the pivot mounting arm of the exterior alternator housing is located (Pivot it the term I am using for the 1/2" bolt that is closest to the crankshaft that is the last thing to be loosened or tightened when taking an alternator off or putting it on.) When you later take this reconfigured alternator to Auto-Zone to have them test it for you on their bench alternator set up, the guy is gonna twist THIS alternator around in his hand several times trying to figure out how to mount it on the bench test device, but once you tell him it's from your Pantera, he's just gonna make everybody else wait!!!
5) Get out an Allen Wrench that fits into the shaft of the alternator and get your Crescent Wrench out and take the pulley off the new NAPA 100 Amp "rebuilt" alternator.
6) Take the passenger seat out of your Pantera (I hate doing this, but there are some neat Allen Wrench tools sold at Auto Zone that have a little hexagonal ball at the end which allows you to turn the allen head bolt from an angle ($18.00), plus they didn't break when I used them for removing the alternator pulley...worth it!!!) Take off the firewall, etc.
7) Get some tape and make labels for the four (4) wires you are going to be removing from your old alternator. Lable them: BAT, GRD, FLD, STA, put these LABELS ON THE WIRES, and leave them there forever. Remove the old alternator. Notice how the new alternator has different electrical connections for the FLD and STA, sort of recessed into the alternator, (and attached to that little ceramic package with the brushes you were working on earlier) What this means, is I had to buy a little electrical connectors variety pack from Auto-Zone for $10.00. (I'll let you print this recipe out and put together your own shopping list!)
8) Remove the old alternator, remove the cooling fan attached to it just under the pulley, attach the smaller, old fan to the new 100 Amp alternator, but do not tighten the pulley on yet.
9) I had to do several test fits to see how things were going to fit before I cut any wires, and here's what I learned: I had to go to Home Depot and get a 5/8" splice made of brass and some hose clamps to lengthen the heater hoses to go over the top of the alternator, better get 2 hose barbs at $1.78 each and back to Auto-Zone for another 1 foot of the best 5/8" I.D. heater hose they got. I had to remove the dip stick bold and clamp to make room, but the alternator wat going to hold this stuff firmly in place, oh and the dip stick point of entry to the engine block was leaking, so I pulled it our a little way, cleaned it and gooped it up with Black Silicone sealer to reduce the oil spotting on the garage floor....
10) While at Auto-Zone (again) I had the old alternator tested (14.5 Amps) and the new on tested (18.5 Amps) This means I got it back together right, and a four lead alternator to go with my stock electrical system four lead set-up!! While at Auto-Zone buy a bunch of fan belts that are very close in size to the old fan belt size, ask the guy to let you go back there with him, tell him this is a Pantera "he's helping you with" you're gonna want them and will take most of them back later.
11) Put this new alternator in, push it as far as you can to the right to use the smallest belt you can, and put the belt around the pulley and then put the pulley onto the alternator, see, in a minute your gonna have to bang on you metal firewall cover to allow for some extra clearance, and it's not gonna be a problem with that fine leather covered firewall/bulkhead cover, but I got blisters from the hammer action....
12) Tighten everything back up, fire up the BEAST and go for a test drive, just seems to respond a little quicker with the throttle and starts up a little quicker too. Now that's what I call a side effect, YEAH!!!!
P.S. Next I gotta pull out the window motors and sand off the rust that is causing thes things to respond a little slower than my 2001 Toyota 4x4 windows (maybe a parts donor???, nah, gotta get to Auto Zone while the Pantera is on the operating table)
P.S.S. Need some brass gears for the windows project, so if someone's got some use one at a small discount, let me know soon please.
Original Post