Alternator brush check.

I finally broke down and decided to check my alternator brushes. I pulled the cover, and after some calibrated hammering (rubber of course) to release the gasket, I had a peak. The brushes do have wear markings, but i'm not sure how to tell if they are bad. If i can see markings are they too worn? or should I be able to see the markings if they are still good? I tried measuring them for the 10 mm spec, but is that supposed to be total brush length or exposed brush when installed? i'll attach a photo I took with it apart.
I also noticed while i was in there, it was pretty dirty, it seemed there was oil in there, is this normal? is it possible a seal is gone between the rotor and the engine? I also noticed a small drain hole in the bottom, at first i thought i had chipped it, but then i cleaned the crap out of it and it looks too intentional. If the casing has a drain hole (for water maybe?) it should not be lubricated by the engine, so I think I have a bad seal. I've attached photo's of the drain hole as well.

Any help would be appreciated.

 

I just seen a post earlier today and it was 10mm from what is exposed. Sorry can't give you an answer to your other ?'s

 

Those scribed lines in the in the brushes are the "wear lines", and show when the brushes have reached the end of their usable service life due to wear. Yours still show some usable length left in them.

Brushes can also deteriorate and change their electrical characteristics due to heat and oil/moisture absorption.

 

I don't believe a drain hole is stock.

There shouldn't be any oil in there though. Seal leaking at the rotor shaft.

 

I just got another cover to polish up while mine is on my bike and I have the same thing on it. What it's for I couldn't tell you!

 

At least i know for sure that the hole is normal, thank you. Unfortunately, the oiled alternator means another thing to fix. I hope i can change the seal by pulling the alternator rotor, i hope i don't have to crack the case. I'm guessing the hole is for moisture draining.

 

Your brushes have quite a bit of life left in them Killer. Those lines you see are your wear lines and you have a lot of miles to cover before you get close to them.
I've got a drain hole in my cover too, normal I guess.
As for the oil and junk, your alternator shaft seal is bad. Source a new one and get the seal carrier o-ring while you are at it. Easy day replacing that seal, once you get the rotor off of course.

 

How long do the brushes last for? I have like 21,000 km on my bike. What if the seal of the cover was not all there. Will that need to be replaced?

 

Thank you all for the replies. I'm glad I have some life in the brushes. Robert, it sounds like you may have been through this before. I'm going to place an order from chacal right away, would you recomend the rotor puller, or will a well stocked autmotive shop (my dad's) have a tool that will work. Basically i'm wondering if a "specialty" tool is required.

Edit: Nevermind, I searched more specifically and found some posts related to this.

 

Killer, I'd buy the tool from Chacal. You could just figure out the thread and diameter if you are only going to do this once in a great while. I sourced my bolt from a local hardware dealer and after a few uses, it's getting chewed up.
Leadboots, fear not! The cover gasket is not an imparitive but is useful for sealing out the weather and such. I would suggest you use one.
As for brush wear, I couldn't even hazard a guess as to how long they last. I've got 80K on my Max and the brushes don't look very different than Killers. Take that as a comparison, it's a judgment call at best.