Bought a bike today, added on the rear rack, and adjusted the breaks too!

[eyePod]

Everything seems to be working correctly now.  The break line was rubbing against the rear rack where it mounts to the seat.  Had to adjust the v portion to put it above the rack mount to avoid the rubbing.  Will use it on the way to the gym tomorrow morning... Hopefully I won't crash at all!

Got the bike Schwinn Crisscross, helmet, rear rack, and a u-lock for 153 from the bike store (frame alone would be 50-60 on CL, 119 on that priceonomics, so I feel like I got a decent price plus contributed to a local shop).  Good working order except for seeming to have issues getting the chain to get onto the largest gear near the pedals.  That will be my next project.  It's still useable the way it is now though and I feel pretty good doing some maintenance on the bike/learning how the break system works!

[jnik]

Good working order except for seeming to have issues getting the chain to get onto the largest gear near the pedals.

I presume you mean you're having trouble shifting the front derailer onto the largest chainring? Could be one of two things:
1) High limit screw too tight. This is the easy one. On the front derailer, there should be two screws labelled H and L. Try to shift onto the largest chainring--push the shift lever as far as it can go. With a flashlight you should be able to see the far end of the H screw inside the mechanism. If it's touching something, back it out a little--this should let the derailer move out more and shift onto the large chainring. It should be adjusted to allow shifting, but not throw the chain off the outside.
2) If the high limit isn't touching, it's not the issue. You'll need to increase the tension on the front derailer cable. The cable attaches to the derailer at a hex screw, loosen that a little and pull more cable. (A third hand, literal or figurative, helps.) Make sure to tighten it back down well!

AASHTA: http://www.sheldonbrown.com/derailer-adjustment.html

Also, I hope you're working on the brake system, not the break system ;)

[eyePod]

Well, apparently the BRAKES loosened up overnight, so I must not have tightened something down well enough, so I felt like I did BREAK something.... Good thing for front brakes too!

Either way, I showed a friend what my issue was with the bike on the ground, and of course the chain pops right onto the large gear on the front derailleurs.  I don't feel confident that it will continue like that in the future though.  Thanks for the website and insight though!

[GuitarStv]

Nice score!  Remember to keep the chain well oiled in the winter, it makes a big difference.  Now you need some kitty litter panniers so you can haul groceries:

[naners]

eyePod, re: brake rubbing on rack mount, did your frame have seatpost braze-ons for the rack? If so, did you use the inner openings rather than the outer ones? That often fixes problems with rack-brake interference. 
Also, if you haven't already heard of sheldonbrown.com, it's an outstanding resource for DIY bike repairs. Have fun!

[eyePod]

I have seen the sheldonbrown website.  Tons of info and looking through it when  I have questions.

The rack only had one screw that mounted on the seat post of the frame.  It didn't use the two holes there.

I've taken it out a few times now with the re-adjusted brakes and I think that I have them working well now.