Decided to replace the brushes on my 200,000 mile alternator as a PM today. First I removed the adjusting bolt, locking bolt, nut and pivot bolt as per the FSM. Then removed the three 12mm bolts that hold the power steering reservoir in place and moved that forward and to the side. I was concerned that it might leak but it didn't. To get the alternator loose I had to lightly tap downwards at the upper pivot point using a brass drift and hammer. Couldn't wiggle the alternator out with the large oil filter I had just put on, so pulled the filter back off, and the alternator came right out. If using the small filter you might not have to do this step.
Got the back cover off no problem after removing the three 10mm nuts and one 10mm bolt and the 10mm nut and plastic insulator on the side. The two Phillips head screws holding the brush holder in place are soft and were in very tight. One of them started to deform so I backed off, got a better fitting #2 Dewalt Phillips bit on a handle (for downward pressure), put about 1/2 drop of PB Blaster on each screw, tapped on the screws with the bit in place, then applied steady pressure and they came loose.
The brushes were not as worn as I would have expected after so many miles; there is still about 3mm of usable brush length. To measure that I put the brush pack back in and made a light score mark on one brush then pulled the pack back out. The slip rings looks good, hardly any wear by feel, I just cleaned them up with some quick dry electronics cleaner on a paper towel and blew out the carbon dust with compressed air.
Holding the alternator up to my ear while spinning the pulley I could hear some very slight grinding, whirring, intermittent tick/click sounds like the bearings are getting dry and/or worn; there were different sounds at the front and the back. Now I'm thinking that I may just put the old brushes back in which could be good for at least 50,000 more miles instead of using the new brushes. I figure I'll either have to rebuild this one or get a remanufactured unit sometime before the old brushes wear out.
Got the back cover off no problem after removing the three 10mm nuts and one 10mm bolt and the 10mm nut and plastic insulator on the side. The two Phillips head screws holding the brush holder in place are soft and were in very tight. One of them started to deform so I backed off, got a better fitting #2 Dewalt Phillips bit on a handle (for downward pressure), put about 1/2 drop of PB Blaster on each screw, tapped on the screws with the bit in place, then applied steady pressure and they came loose.
The brushes were not as worn as I would have expected after so many miles; there is still about 3mm of usable brush length. To measure that I put the brush pack back in and made a light score mark on one brush then pulled the pack back out. The slip rings looks good, hardly any wear by feel, I just cleaned them up with some quick dry electronics cleaner on a paper towel and blew out the carbon dust with compressed air.
Holding the alternator up to my ear while spinning the pulley I could hear some very slight grinding, whirring, intermittent tick/click sounds like the bearings are getting dry and/or worn; there were different sounds at the front and the back. Now I'm thinking that I may just put the old brushes back in which could be good for at least 50,000 more miles instead of using the new brushes. I figure I'll either have to rebuild this one or get a remanufactured unit sometime before the old brushes wear out.
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