97 Disco Alternator issues

I have had some fun and games with my alternator recently; here's how it went: original factory alternator started making quite a bit of noise over a couple of weeks so I took it in for a rebuild (new bearings and brushes); the rebuild lasted about a week and a half when the noise started up again and then the battery light went on; I removed the rebuilt and took it back to the shop and found out that it was smoked - beyond repair; I was given a discount (cost of the rebuild) on a new unit (remanufactured) put it in and within a couple of weeks this one was making a racket - I just had the bearings replaced on this. I went through all pulleys in line, air conditioner pulley and power steering - all are in good order; I replaced the serp belt with a new one; I pulled the belt tensioner off and replaced the bearing on that pulley just to be certain.

Am I overlooking something here because its getting a bit frustrating chasing the same problem around? For example, do Land Rover alternators on the serp belt system not like to be rebuilt? Can the belt-tensioner main spring actually get stronger over time (my experience as a gunsmith always led me to believe that springs' tension weakens over time)? The tensioner is tough - but it does flex when you lean on the belt.

I talked to my friend , Martyn Russell - a former Land Rover UK employee and he was stumped on this too - all he could say was that maybe the new bearings are just not up to the standard that Disco Landy's need - remembering that the alternator is on top of the pulley system and the big serp belt pulls down the hardest at that point?

Latest sitrep - the new bearings seem to be holding (after one day) but I am getting paranoid now as when I put my hand on the alternator, after running the vehicle around town for awhile, it seemed pretty hot. How hot should they get or how hot is still acceptable?

Perplexed - and ideas out there?

You will get plenty of heat in an alternator just due to the coil windings heating up.

As you say, the spring can only weaken with time, not strengthen, if the tensioner deflects on moving the belt by hand then it's likely to be ok.

You should be able to pass the problem over to the firm that rebuilt and then supplied the remanufactured alternator.

Hello l3on,

This makes perfect sense to me - it also checks out with what my Landy UK pal has been telling me.

I really think it boils down to dodgy bearings in the end.

thanks for your feedback - my alternator paranoia is starting to fade a little,

Wolf