Lift the hold switch free from its housing on the rear panel. Don't remove the hold switch completely at this time, because it is connected to the same cable as the headphone jack.
If you're just trying to remove the rear panel, you can skip Steps 30 and 31.
If your replacement headphone jack includes the white plastic hold switch, simply reinstall the replacement headphone jack. When replacing the hold switch assembly note the locating pin near the hole the silver screw position, concentrate on locating that and the rest falls into place. Once it's all screwed in remember to peal the backing tape off the contact pad just along from the jack.
If your replacement part does not include the plastic hold switch, follow the next steps to transfer the plastic hold switch to your new headphone jack.
Remove the single Phillips screw nearest to the hold switch.
Lift the plastic portion of the Hold switch away from the orange ribbon cable.
Ensure that the black notch lines up with the gray slider during reassembly of the switch (see picture 2).
Use the small iPod opening tool to carefully peel the orange ribbon cable and attached black Hold switch up from the metal backing.
When re-attaching the replacement Hold switch, make sure the two small posts on the back of the switch are aligned with the two holes in the metal backing.
The headphone jack is part of an assembly, on a cable with the hold switch. We sell this assembly for thin iPod classics (80, 120, or 160 GB) here, and for the thick (160 GB) variety here.