An improved remotely adjustable gland follower for a stuffing box of a rotary or reciprocal mechanical device is provided. In one embodiment of the invention, the gland follower includes a body portion with at least one cylinder having a fluid inlet at the power end and a piston. The piston has a hydraulic end positioned within the cylinder and an opposed packing face surrounding the shaft and configured to extend into the seal cavity. The piston engages and compresses the packing in the seal cavity when pressurized by fluid introduced into the fluid inlet at the power end of the cylinder. At least one o-ring groove may be formed in the hydraulic end of the piston to receive at least one o-ring for improving the hydraulic seal in the cylinder.