1989 S4 115 amp alternator rebuild - Need help with parts and procedure

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11-11-2011, 04:41 PM

#31

Bill Ball

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I'm glad now I didn't attempt to replace the slip-rings or the rectifier.

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11-11-2011, 05:12 PM

#32

waynestrutt

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Years ago ( 87 )I had problems with the alt in my 1980 928.I had the unit in and out so often I considered using wingnuts. On the bench it put out 14 +volts but installed would not turn off the alt.charging light unless rpm was over 4g.Regulater, brushes, diodes etc all replaced to no avail. I discovered that when tightening the mounting bolts, adversely affected the output. The PO also reported having had alt. problems and tall I could figure is that he repair shop when replacing diodes dropped a small pc of solder between the circuit board and a diode which shorted the output. Small and not in clear sight it took 3 months to find the problem.

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11-11-2011, 08:19 PM

#33

Hilton

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Quote:

Originally Posted by T_MaX

The Range Rover article that Bill references lists:

Rear-small: 6203 RS or 6203 2RS (rubber seal) 17mm ID x 40mm OD x 12mm W
Front-large: 6303 RS or 6303 2RS (rubber seal) 17mm ID x 47mm OD x 14mm W

I was hoping someone could verify these number.

For the Bosch alternator on my '89 S4 the bearings were:

Rear - 6201 2RS (original is C4 clearance)
Front - 6303 2RS (original is C3)

They should be the same for all 928's that use the Bosch alternator (85-95).