The trend in modern plain journal bearing design is towards a reduction in the relative bearing width; this results in reduced machine bulk and bearing losses, but has the disadvantage of increased bearing wear, particularly at starting, stopping and the reversal of motion. A method of reducing this wear problem is by means of hydraulic jacking, or the separation of the load carrying surfaces by the introduction of high pressure oil into the clearance space, through suitable feed grooves. The article describes an analytical solution to the problem of hydraulic jacking. The following solutions are presented, giving full performance characteristics. (1) Single- and twin-axial feed grooves, end leakage neglected. (2) Single- and twin-axial feed grooves, concentric journal, finite length bearing (approximate solution). (3) Single- and twin-axial feed holes, concentric journal, small diameter feed holes (approximate solution). Some experimental verification is given for the theory of the axial feed groove arrangement, both the single grooved and the twin grooved arrangement.