Originally Posted by
Jeff Wills
I'll bet my back teeth they're 100% interchangeable.
I wouldn't be too sure. The Caliente was Schwinn's bottom bike, still using an adapter claw for the rear derailer, stem shifters, etc. I'm willing to bet it used longer reach brakes than the short reach Shimano units from the ebay ad. Measure your reach before you buy.
http://www.sheldonbrown.com/calipers.html#reach
If you are able to make use of those Ultegra units, they are very nice and will work much better than the flimsy calipers that are probably on your bike now. Although your brakes can probably be made to stop the bike effectively, just not feel as nice or solid.