Back when I bought my 40, I had a hunch that the generator wouldn't last too long. I was
correct! So, one day in Novmember, when I was visiting a local 4x4 shop, I tried to start my truck, and found a
dead battery. Pisser. I didn't know then what I was in for!
I knew that I would mount the alternator in the normal location, on the front, passenger side of the block. When I
test fitted the alt. bracket, I found that two of the coolant hoses, and the fuel line were in the way. Moving the
fuel line was easy enough, but the coolant hoses caused some problems. For the new coolant hoses, I went to the local
parts store, and found a couple hoses of the correct diameter, which also had a bunch of angles in them. I wasn't sure
of the exact angles I would need. I ended up cutting part of the metal "T" pipe so that I could match the new coolant
hoses. Basically, I had to move the top coolant hose lower, so that the alternator bracket wouldn't rub through it.
Once the hoses were modified, I started on the alternator. Originally, I was going to use a Toyota alternator I had
bought just after buying the truck. Those plans changed when I fried it trying to wire it. Hint #1: Don't bother with
an alternator you have laying around. Reasons to follow later...
I went to the local Pep Boys, and bought a internally regulated, rebuilt Delco Remy alternator, part # 7127MDP. It
cost about $45, including the core charge. Puts out 105 amps, more than enough power for me! This alternator isn't one
of the popular "one wire" alternators, but I was more interested in getting my 40 back on the road, than waiting for a
back ordered alternator.
I had to grind a little off the bottom of the alternator bracket, so that the fan blades on the alt. wouldn't rub.
Nothing major. I also had to grind a little off the mounting point on the alternator, so that it would mount to the
bracket. Nothing major there either. I used the original bolts, for now at least, but I'll probably replace them later.
On this alternator, the pulley is smaller than the original Toyota pulley. Pep Boys didn't need the Toyota pulley for
the core charge, so I had them remove it from the dead alternator. I'll install the Toyota pulley later.
The wiring was next. This alternator is wicked easy to wire! Here's how I wired it up:
Bottom line, make the swap easy, don't use an old alternator you have laying around. For about $60 total, I have a new
(rebuilt) alternator, which has more than enough juice for anything I'll have in this particular rig. Wiring was easy, and
I don't have an external voltage regulator to worry about any more.
Email me if you have any questions, or want some pictures of the installation.
Alternator Where it goes
---------- -------------
"B" post to + post on the battery
"1" post to switched side of the ignition cylinder
"2" post jumper wire to "B" post of the alternator
If you don't have the one wire alternator (like me), then you also have to solder a diode inline with the wire from the
"1 post on the alternator. If you don't install the diode, your engine won't shut off when you turn the key off. I
don't have the part # for the diode. Instead, I went to an alternator shop, told them what I was doing, and they sold me
the diode for a buck. Remember, the band on the diode should be pointing towards the alternator. After the diode was
soldered in, I shrink wrapped it. Rumor has it that you can buy an alternator plug from a GM dealer, but I stopped over
there twice, and got the same response, "why don't you head over to (insert local auto electrics shop here). They can hook
you up." I don't think you have to do the diode thing if you have the one wire, but I'm not sure. I used a 50 inch
v-belt, you may need a different size for your rig. Note that I also didn't wire in the ammeter in the instrument
cluster. I'm going to install some AutoMeter gauges in the near future, and will wire it then.