Before replacing the alternator on your 1996 Subaru Legacy, check the voltage output to make certain that the alternator is at fault and not the battery. Make sure the battery is fully charged, and check the voltage, which should be 12.75 volts or very close. Have a helper start the car while you watch the battery voltage (with a voltmeter). If the voltage remains above 10.5 volts, the battery is good. If it drops below 10.5 volts, replace the battery (a bad cell can harm the alternator).
Loosen the adjusting bolt on the top right of the alternator as you are facing it. Use a wrench to loosen the bolt. Push the alternator down to loosen the tension on the belt. Lift the belt off the alternator.
Disconnect the negative cable on the battery of the Subaru, using a wrench. Remove the large positive wire on the back of the alternator with a wrench. Pull the electrical connector out of the alternator. Remove the alternator adjusting bolt and the lower mounting bolt, using the appropriate socket. Lift the alternator out of the engine compartment.
Install the long mounting bolt in the new alternator. Install the alternator in place, then thread the lower bolt into support the alternator. Install the upper adjusting bolt finger-tight. Attach the battery positive wire to the back of the alternator, and tighten the nut with a wrench. Push the plastic electrical connector into its slot.
Tighten the lower mounting bolt just to the point that you can still rotate the alternator. Install the alternator belt, pull the alternator until the belt is tight and tighten the adjusting bolt. Tighten the lower mounting bolt. Attach the negative terminal to the battery.
