alternator - how long do they last ?

[lexus400]

I have a '91 LS with a 140k miles. I have done all of the major tuneups

myself and replaced the drive belt and hoses proactively. The nagging thing that's on my mind is the alternator. I'm hoping a couple of people can give me an idea when theirs have failed. Voltage is good, lights are bright etc., but I would rather replace it before it goes if I'm getting near the max life span. If there's anything else you think of (other parts) feel free to let me know. My PS pump is leaking, I don't think that will get me stuck but I should change it soon. Anyone done that on this car ?

[Russ]

There is a known problem with the Power Steering pump on this car. I have a 93 LS400 and had the Power Steering go at about 100k. You shouldn't leave it leaking as the leak may cause damage to the Alternator and make it go faster than it should. I had the Alternator go at 130k, but I've heard that's only because the leak with the Power Steering affected it as the Allternator is right under the PS pump.

[AWJ]

I concur. From all the testimonials I have seen, if the power steering pump is leaking - your alternator is gonna fry. If there is no leak, the alternator will last indefinitely (considering proper care is taken).