Abstract: A hydraulic machine has a cylinder body with first and second ports and a plurality of cylinder bores disposed radially with openings through a side surface. Deformation regions, formed around each cylinder bore opening, expand and contract in response to pressure changes in the cylinder bores. A continuous band extends around the cylinder body closing the cylinder bore openings and applying a pre-stress compressive force to each deformation region. A plurality of pistons are slideably received in the plurality of cylinder bores and a plurality of valve arrangement couple the cylinder bores to the first and second ports. A shaft with an eccentric cam drives the pistons to slide within the cylinder bores. Each deformation region distorts in response to pressure in the associated cylinder bore wherein the circumference of that cylinder bore becomes more circular as the cylinder pressure increases.