Cadillac 2005 XLR Owner's Manual page 104

Notice: Pressing the retractable hardtop button
when the hydraulic pump valve is open could
damage the pump. Always close the hydraulic pump
valve after the retractable hardtop has been closed
manually.
6. Pull both sides of the rear tonneau over-center link
down to unlock the linkage.
2-48
7. Move the rear tonneau rearward and up to the
stored position. Pull from the center of the
tonneau to keep pressure even. The rubber bumper
on each corner will fit against the underside of
the trunk decklid.