An unclamp delay valve for delaying release of hydraulic pressure in a hydraulic holding device. The unclamp delay valve may have a check valve allowing fluid to flow between an inlet port and an outlet port when held open by a piston translatable within a piston chamber. The check valve blocks fluid from flowing between the outlet port and the inlet port when released due to hydraulic fluid filling the piston chamber and translating the piston away from the check valve. To reopen the check valve, hydraulic pressure is released via the inlet port and slowly drains from a small orifice fluidly coupling the piston chamber and the inlet port, causing the piston to return to again open the check valve. A delay is thus created by the time it takes for the piston chamber to drain, thus opening the check valve to release hydraulic pressure therethrough.