Hydrostatic shoe with face seal

A hydraulic piston motor, comprising:

• a swashplate;
• a plurality of pistons configured to engage the swashplate;
• and
• a plurality of shoes disposed between the swashplate and the plurality of pistons, wherein each shoe includes:
• an upper portion configured to receive a piston of the plurality of pistons;
• a lower portion configured to contact the swashplate;
• a counterbore formed in the lower portion;
• a vertical channel extending through the upper portion and the lower portion into the counterbore;
• and
• a seal disposed within the counterbore and extending around a circumference of the counterbore, wherein the seal is a C-shaped seal, the C-shaped seal having an opening toward a center of the counterbore.

A shoe for use with a hydraulic piston, comprising:

• an upper portion configured to receive the hydraulic piston;
• a lower portion configured to contact a swashplate;
• a counterbore formed in the lower portion;
• a vertical channel extending through the upper portion and the lower portion into the counterbore;
• and
• a seal disposed within the counterbore and extending around a circumference of the counterbore, wherein the seal includes a face seal and an elastomeric seal, wherein the face seal is configured to contact the swashplate and the elastomeric seal is disposed between the face seal and the lower portion and wherein the face seal is annular having an inner circumference and an outer circumference, the face seal including:
• a groove formed around a middle circumference of the face seal, the middle circumference being between the inner circumference and the outer circumference;
• and
• a face seal channel extending from the inner circumference to the groove.