Depending upon how "new" your 1860 is, the bolt removal will be different than the instructions on the website pointed out by Sean Thornton.
The latest manufacture by Uberti has changed the bolt and firing pin extension assembly to a system more like the original Winchester design. In the new one, the link pin holds the firing pin extension as well as the links, and has a small wedge similar to the original Winchester firing pin retractor that holds the extension in place. Uberti calls it a firing pin extension toggle, and is part number 721 in VTIgunparts exploded view of the 1866 and 1873 rifles.
Push out the link pin (part 105) at the bolt and the extension can be removed to the rear after the toggle (721) is removed. This system is much stronger than the previous 1/16 inch cross pin.
For some reason, VTI has not updated their exploded view drawing of the 1860, but refer to the new parts in their descriptions of the 1866 and 1873 as fitting the 60 Henry, the 66 and the 73.