Abstract: A brake or clutch master cylinder has a slightly stepped bore with angularly equispaced grooves extending from the large diameter step into the small diameter step across the seal of the piston in its rest position. The fluid reservoir communicates with a groove of the large diameter step via a radial port.

Abstract: A hydrostatic transmission (10) includes a variable displacement pump (12) for driving a fluid motor (14) in first and second directions. First and second high pressure conduits (20,22) connects the pump (12) and motor (14) in a continuous fluid circuit. A control pump (40) supplies make-up fluid to the first and second high pressure conduits (20,22) and simultaneously provides pressurized control fluid to a system control (50) for controlling the operation of the hydrostatic transmission (10). First and second low pressure conduits (24,26) are respectively disposed about the first and second high pressure conduits (20,22) and defines first and second spaces (28,30) therebetween. A pressure control arrangement (32) is connected to the first and second spaces (28,30) to control the maximum pressure level in the spaces (28,30) upon the failure of one of the high pressure conduits (20,22).