Originally Posted by Mark G

Disco 2,

Yeah we have shops here, and one is really cooperative with working with guys like me thatprefer to do it myself, the other one isn't. I can't see paying a shop to do something anybody with average mechanical skills could do in about 30-50 minutes. To me, it's a challenge, fun, and ya can save abunch of money over getting a rebuild. Plus, like I said, I wanted to keep it original.Shinnynew plating isn'tas important to me as theLand Rover sticker on it.There aren't hardly any parts to an alternator.With a Magnetti Marelli Alt, all the main wear items are on the back of the alternator, easily accessible and ya don't need to mess with the bearings to change any of this stuff. It's sooo easy, in fact, ya could change the brushes/regulator right on the vehicle if ya wanted.

On a high mile vehicle8times out of 10 the problem is worn brushes. Universal brushes are only about $ .50 a set. If ya let them go too long they wear out, arc to thecommutator and wear the contact surface on the shaft. That's when most people have alternator problems and get a rebuild. If they would have serviced it eariler, a couple bucks would have saved them $300. This summer I replaced the brushed on my Caddy alternator (230k mi) and our Jeep G/C (190k mi). Brushes on both were almost worn out.
Other problems could be a failed voltage regulator or a bad diode. In my case, the Autozone on-vehicle test indicated it was a bad diode. For this alternator the diodes are part of a rectifier assembly and becuase L/R is not a common application, vs a Ford/GM/Toyota, I had to get them from my alternator shop. That cost me more than online sources or catalog. I think it was like $40. While I was in there, I also replaced the regulator/brushes assembly (they come as one) with OME and that was about $40. Ultimately I didn't need to as you will later find out, but my thought was to replace the main wear items while I was in there. Putting these on the alternator took maybe 1/2 hr. The bearings look/felt good and I didn't replace them. Sometimes I do replace the bearings, but usually not. Bearing failure isn't very common (although it does happen), and usually the altwill whirl loudly for quite a while before it siezes up and causes other damage. I've run a lot of vehicles well over 200k and never have I had an alternator bearing fail. If ya hear them whirl ya can replace for a couple bucks before it leads to a $300 repair. Apparently a lot of shops and rebuild outfits also repack and reuse the bearings. I also ohmed out the field and other coils and they checked out Ok.

After all this, the alternator acted the same as before the work I did. I had the rebuilt alternator tested a couple times and it tested good. Ultimately the problem turned out to be that the previous owner (or mechanic) put the serpentine belt on incorrectly and there wasn't enough belt contact area around the alternator pulley. So, it would slip when under higher amp draw. I posted more about this in another post. My bad, the Autozone test sent me down a path of looking for an electrical problem. Usually I'm pretty good about looking at the problem from a more global perspective, but did not do so this time. Just goes to show that high tech tests are no substitue fundamental troubleshooting. Also, my L/R does not have a belt routing sticker or diagram under the hood or in the owners manual, to refer to. First time in all my years I ever had a belt installed incorrectly. It works great now.