97 STS alternator frozen

The shaft and rotor dropped too far inside the housing and made the fan scrape against the housing making a hideous squeal. I took it off and took it to school and my instructor said that whoever rebuilt it did a piss poor job and thats y it failed.

I got a used one frm a friend of mine that won't maintain a steady voltage. The spec is 13V-16V but the actual floats between 13.2 and 13.5, sometimes 13.8. My question is does a bad regulator cause that or could the rectifier and the regulator be bad? I havn't taken the used one back off the motor yet to test it. Also when I start the car with the used one the voltage takes about 3 seconds to go up to a steady voltage.

When the broken alternator was good the voltage was always over 14.

The reason I'm doing this is because of a lack of money right now but its also a good learning experience. This is the first time I've taken an alternator apart. I believe the regulator and rectifier in the broken alternator are good. I bareley had loss of output before the old one locked up. As soon as I took the fan and pulley off the old one it turned with no problem but the bearings need to be replaced

I would like to make one working alternator from the two.

Thanks for any help. Gonna test the old diodes in a few.

At 1500 rpms, adjust alternator load to 13 volts, then check alternator amp output. If the amp output is within 15 amps of the alternator amp rating, it's doing all it can. As far as alternator overhaul, I use what is in the kit.

Thanks. I'm gonna test the output at school. I don't have a load tester at home lol. I just don't feet comfortable with the voltage output hanging around the low end of the spec. Also gotta still test the other parts to see what's good vs bad.