Alternator Rebuild

by Author Unknown

Most manuals don't tell you how to rebuild the alternator! Please read this whole posting first to decide if this is something you have the tools or time're only going to save about $40 per alternator. Also, I should define the 2 main parts of the alternator: The rotor is the "go-roundy" and the stator is the "standy-stilly".)

1. First, you need something to get the pulley nut off. I use my half inch impact wrench....ZZZZZZZing! Off pops the nut! The next easiest way is to loosen it in the bus...with the belt on and a rag lodged in the pulley (don't use a screw driver and mess up the pulley). There is some sort of wrench to hold the pulley, but I have never owned one.

2. Next, you need a bearing puller. I got the cheap JC Whitless set with all the pieces. On alternators, it works great! It has tapered plates (with cutouts) that clamp around the bearing and then the puller part threads into these. I first use this plate to get the pulley off. Slip the plate behind the pulley and locate the puller thrust screw on the end of the shaft (use the flat end insert to avoid damaging the end of the shaft). DO NOT HAMMER OFF THE PULLEY BY HITTING THE END OF THE SHAFT.

3. Next the long clamp screws and nuts have to come off...the three long jobs you see on the outside of the stator. I use a hand impact screwdriver I still have from my motorcycle days. You whack this thing with a hammer and the end turns! Make sure you take off the nuts on the back side, as well as the tin cover and the electrical connections underneath before you unscrew these.

4. With the clamp screws out, you can separate the front housing (pulley end) from the stator. I use a piece of wood to tap on the mounting supports until the rotor and housing come off of the stator as one unit. Now you use the puller to get the housing (with bearing) off the front of the rotor. Rig the puller backing plate behind the housing and pull it off the rotor just like you did with the pulley in step 2. Unscrew the bearing retainer inside the housing and take the bearing out. Use the puller to take the other bearing off the end with the collector (the collector is the double copper ring job on the opposite pulley end). BE CAREFUL NOT TO DAMAGE THE COLLECTOR. A scratched and nicked collector is our enemy.

5. Hang in there. The hard part is over....well almost. There is a brush holder in the back of the stator housing. It's usually white thermoset plastic. It has a couple screws holding it in and a spade terminal connecting it to the rectifier (diode) plate. You have to take off the rectifier plate to get it out. Once it is out, put it in a bag with the used bearings and go to your local electrical automotive place ( guys use FLAPS, I use LEAPs). Show all the stuff to the guy behind the counter. Make frequent references to how you did it all yourself. Smile proudly. He'll probably sell you the brushes for $2 and the bearings for $3 each. (Don't feel bad, he probably paid pennies for the brushes and under a buck for the bearings!) BTW, these parts are all common to many different cars (the bearings are probably the same on a chevy!)

6. Desolder the old brushes and resolder the new ones. Do them one at a time to duplicate exactly how they are located. Be careful not to wick the solder too far up the brush leads. When you are done, you will need to push the brush up through the holder until the end of the spiral spring is against the side of the brush. This holds the brushes in a lifted position for assembly (this is really a neat design!). It actually is easier if you do this trick before you solder the leads.

7. Put everything back did draw a diagram of where the washers, wires, and screws went, right? You can sand the collector with 400 grit paper and clean with contact cleaner (before you put the bearings on), if you want. If it looks clean, I let it go. If it's deeply rutted, the LEAP can turn it (about 8 bucks). For that matter, the LEAP can solder the brushes in for you too...but you're eroding your bottom line with each step he does. You can get the bearings on by pressing (the right way) or taping on with a block of wood. I use a big honking vise (horizontal press) with sockets for spacers.

Just before you close up the electrical connection end (opposite pulley), put a small screw driver or ice pick through the opening above the brush holder and snap down both brushes toward the collector. You should be able to see the spiral spring ends position themselves on the tops of the brushes. Button the rest of it up and put it back in the bus.

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