Just go ahead and replace the alternator?

[Formerly Steve Wilkinson]

Car runs just fine ('83 SC), but today I noticed that my voltmeter was indicating a charge of no more than 12.5 volts. Confirmed that with a multimeter at the battery, at 2,000 rpm--12.5 volts. "Resting" voltage of the battery, engine off, is about 11.8 volts.

Battery is a six-month-old Optima, and whenever I park the car for more than a few days, I turn off a master switch. Fan belt was replaced about six months ago as well and seems to be tight--no slippage, I can turn the crank by turning the fan.

The alternator was rebuilt/rebrushed by a local alternator shop about 14,000 miles ago, but I'm pretty sure it's the original alternator.

Since these are the Paris-Rhone alternators with integral regulators, should I just go ahead and replace the whole thing?

[Ned nyna 11]

Stephan,

Since the voltage does not increase as the engine revs, agree it's the alternator.

You could remove the regulator/brush assembly and check the brushes first. If they are worn down, there will be no field current and no alternator output current or voltage.

[Formerly Steve Wilkinson]

Thanks, Ned. I'm pretty confident the brushes are good, since they're only a few years and limited miles old. And I see that Pelican has an apparently new line of new (not rebult) high-output Bosch replacement alternators, and I'm always a sucker for yet more gold-plating...