My uncle broke down yesterday, replaced the battery and got his truck back on the road. He was about 30 months into a 72 month battery. Now he is noticing that the alternator is only making about 11 amps at idle. 13 amps at highway speed.

He wants to replace the brushes as the first (and cheapest) step to fixing the alternator but I'm having a heck of a time trying to find them. If anybody has an idea of whether they are serviceable and where available it sure would help. Also, any other trouble area to look for. This a the 3rd alternator for this 300k mile truck and we're not positive it's a 105 amp.

Here's the truck
2003 Chevy Silverado LS Ext Cab 2wd, 5.3 (T), Auto

Here's the current alternator
Remanufactured Delphi, number above barcode=450803901, numbers below barcode 21 798

I've checked eBay, GM Parts, RockAuto, Google and I can't seem to find anything.

 

your best bet and honeslty this will save you and him trouble down the road is go ahead and get a new altenator you wont find many people that sell them anymore like you used to be able to
and are you new to this forum you need to go to the newbs forum and introduce yourself
i hope you stick around on this forum and dotn flake out and leave after you get what you want

 

It sounds like you need to do some testing before deciding that the alternator is bad. Amp output is load dependent, so you should expect it to vary. What is important is if the alternator maintains about 14.5V under all load conditions. You could start by checking the voltage at idle and then turning on various loads to see what happens. If you take it in to most auto parts stores, they will check it for you.
Maybe the battery he had to replace was just a bad one? (Not caused to be bad by the alternator.)

 

good suggestion
and also the testing is free at the auto parts stores
my truck holds at 14.4v constant under all loads that is good but yes batteries can very from naywhere from 12-14 v range
also the auto parts store can test the battery as well