(Original thread: http://www.cb7tuner.com/vbb/showthre...648#post677648)
Summary of why this fixed my problem:
With multimeter on the battery, and car running, I had no more than about 12v, which means the alternator wasn't doing much (some maybe, not much). Overvoltage (more than about 13v) isn't a worn brushes problem, although very low or no alternator output could have instead been something else such as the regulator, diodes, crappy connections internally or externally etc. etc.
But the reason I tried new brushes first was partly because stuff on Hondas tends to wear out before they break --- although aftermarket rebuilt alternators might be a different story. That's why my car has its original alternator back on, even with 250,xxx miles, not an auto parts store rebuilt one.
I got a new set of brushes, courtesy of Monsignor phatdoughnut (thanks again!)
Cost: Somewhere between $10 and $30, depending on if you can find them locally in stock vs. ordering them over the Internet. Use a phone book for the former; Google for the latter. Major chain auto stores will not have alternator brushes. Shops that specialize in auto electrical parts and/or alternator/starter rebuilds are what you want <<< again, if you can find one.
Another option is to punt the whole operation and get a junkyard alternator. Highly recommended you stick with OEM Honda, and have it tested. Cost: approx. $35-$60 for one pulled from a car with less than 100,xxx. <<< Not a bad way to go, when you think about it!
(TypeG told me that how you can tell if it's OEM vs. rebuilt is that the back of the OEM unit is bare metal, rebuilt ones have painted backs.)
OK, here's what's involved:
Step 1) Remove alternator from car.
Step 2) Remove three 8mm nuts from back of alternator, remove the alternator's "B" post plastic insulator (12mm nut). The (B)attery post is the single post where you previously removed the cable that supplies 12v+ juice.
Step 3) Unscrew two screws holding in old brush set. Replace with new, being careful to install the new in the same way.
Step 4) There is no step 4 <<< sorry, an old Macintosh joke
Note 1) When viewed from the side, you'll see that one side is slightly taller/different. Sorry, I don't have that picture but you'll see it.
Note 2) You'll need something to hold back the brushes as you slip the assembly down over the rotor. In particular, you'll notice that there are 2 areas on the rotor, one area for each brush --- with a gap or groove in between. Without something to hold both brushes back sufficiently, the bottom brush will go into the groove, preventing the assembly from seating fully. I used a jigsaw blade, but even that was almost too thick to fit in there. A flatblade screwdriver is definitely too thick.
^^ Don't worry, when get into the project this will make sense.
Note 3) My new brush assembly was a tight fit. The plastic insulator that makes up the bulk of the assembly was slightly wider than the original (less than 1/8" bigger) and it kept catching and I couldn't figure out why. Just pushing a little more did the trick.
So here's the old and new. Note that the old was worn so much (car had 250,xxx miles) the brushes were down at the bottom of their circular wear indicators; you can see them easier on the new one. Another major clue that the old ones were worn was that the assembly easily slid in or out of the alternator, suggesting the brushes were just barely touching the rotor.
Summary of why this fixed my problem:
With multimeter on the battery, and car running, I had no more than about 12v, which means the alternator wasn't doing much (some maybe, not much). Overvoltage (more than about 13v) isn't a worn brushes problem, although very low or no alternator output could have instead been something else such as the regulator, diodes, crappy connections internally or externally etc. etc.
But the reason I tried new brushes first was partly because stuff on Hondas tends to wear out before they break --- although aftermarket rebuilt alternators might be a different story. That's why my car has its original alternator back on, even with 250,xxx miles, not an auto parts store rebuilt one.
I got a new set of brushes, courtesy of Monsignor phatdoughnut (thanks again!)
Cost: Somewhere between $10 and $30, depending on if you can find them locally in stock vs. ordering them over the Internet. Use a phone book for the former; Google for the latter. Major chain auto stores will not have alternator brushes. Shops that specialize in auto electrical parts and/or alternator/starter rebuilds are what you want <<< again, if you can find one.
Another option is to punt the whole operation and get a junkyard alternator. Highly recommended you stick with OEM Honda, and have it tested. Cost: approx. $35-$60 for one pulled from a car with less than 100,xxx. <<< Not a bad way to go, when you think about it!
(TypeG told me that how you can tell if it's OEM vs. rebuilt is that the back of the OEM unit is bare metal, rebuilt ones have painted backs.)
OK, here's what's involved:
Step 1) Remove alternator from car.
Step 2) Remove three 8mm nuts from back of alternator, remove the alternator's "B" post plastic insulator (12mm nut). The (B)attery post is the single post where you previously removed the cable that supplies 12v+ juice.
Step 3) Unscrew two screws holding in old brush set. Replace with new, being careful to install the new in the same way.
Step 4) There is no step 4 <<< sorry, an old Macintosh joke
Note 1) When viewed from the side, you'll see that one side is slightly taller/different. Sorry, I don't have that picture but you'll see it.
Note 2) You'll need something to hold back the brushes as you slip the assembly down over the rotor. In particular, you'll notice that there are 2 areas on the rotor, one area for each brush --- with a gap or groove in between. Without something to hold both brushes back sufficiently, the bottom brush will go into the groove, preventing the assembly from seating fully. I used a jigsaw blade, but even that was almost too thick to fit in there. A flatblade screwdriver is definitely too thick.
^^ Don't worry, when get into the project this will make sense.
Note 3) My new brush assembly was a tight fit. The plastic insulator that makes up the bulk of the assembly was slightly wider than the original (less than 1/8" bigger) and it kept catching and I couldn't figure out why. Just pushing a little more did the trick.
So here's the old and new. Note that the old was worn so much (car had 250,xxx miles) the brushes were down at the bottom of their circular wear indicators; you can see them easier on the new one. Another major clue that the old ones were worn was that the assembly easily slid in or out of the alternator, suggesting the brushes were just barely touching the rotor.
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