2002 MCS Alternator showed 0% all of the sudden after hammering on it to pass slower cars. Battery showed 94% Also lost power steering and battery light came on and several other lights blinked. I know this happens but my question is... Do most alternators just give all the way up all of the sudden? I just figured it would give a low charge before going completely dead. Car has 120,000 miles on it. I purchased another alternator and looked on how to change it out and now I'm thinking I'm gonna have a love/hate relationship with my mini. Thanks for any inputs...

 

Depends what happens. In some alternators (not sure on Mini's or not) they have brushes and a commutator on the shaft. As things spin the brushes keep in contact with the commutator until they are out of brush life. Once this happens it can be a very quick downhill in the performance of the alternator because there is no more contact.

 

At 12,000 miles I wouldn't be jumping to the alternator first, take a good look at the ground strap on the passenger side of the engine, see if it's secure, then take it off and check the quality of the metal, area's near ocean or that have salt on the roads in winter seem to have this $15 part corrode easily or if it's just loose the bad connection will make it seem as though the alternator has failed, which is not unheard of, but less common than the groundstrap issue, in my experience. The ground strap is also cheap and easy to access compared to the alternator.

 

Look at the simple cheap stuff as previously stated....but depending on how the alternator failed (if it did) it could just stop working....if the windings inside had insulation fail, it would turn to a dead short, or if the voltage regulator failed, it may also suddenly stop....
A gradual drop in output is consistant with brush wear, but it is just one way to fail, and usually would happen in high mile situations....(in the old days you would just get an "rebuild kit" that would contain brushes and new bearings, sometimes a regulator, reassemble, and reinstall in some cases).

 

Ok thanks to all, I took the front end off today and replaced my alternator and all is well. I'm back on the road and loving my little buddy again...