Will dry gears in a baitcaster make it feel rough and cause a small grinding noise? My brother's baitcaster seems to have this issue.

Sounds lore like dirty gears.  Not sure how gears would end up dry.

Is there any way to clean the gears without completely taking the gear mechanism apart?

Not really.  You can contact Delaware Valley Tackle, via the link to the right.  They offer a discount to BR members.

If you don't want to take the reel completely apart, you could  open the side plate and spray clean the gear with brake parts cleaner or Electro-clean  and regrease. After closing check for the noise. If it's gone, tear the reel apart for a good cleaning and relube.  If it's still there, It may be something as simple as a loose screw holding the pinion gear retainer plate or, worse case scenario, broken teeth on either gear.  Does the anti-reverse work okay? 

More than likely, old grease is preventing a good mesh of the gears.  If the reel has never been cleaned, that may be all it needs.

I advise against spraying anything inside of a reel. The spray can not be targeted enough and will undoutedly disolve lube in unintended areas. The reel in question needs a deep cleaning.

I advise against spraying anything inside of a reel. The spray can not be targeted enough and will undoutedly disolve lube in unintended areas. The reel in question needs a deep cleaning.

X2.........Big time!......

 

 

Tight Lines All!  

I'll give a x3.  He already doesn't want to take it apart, and spraying degreasing agents on it will dictate a total break down and cleaning of the reel.

And possibly melt plastic components.

I could just see those little springs sitting on the pinion gear never being found again