wide variety of tools on the vehicles oil is expelled from the implement circuit through a pair of conduits 26 and 28 conduit 26 returns such oil directly to the tank while the conduit 28 interconnects the implement circuit with the combined fluid motor and pumping apparatus 10 the conduit 28 contains an orifice 29 which is sized relative to the implement circuit back pressure to direct a relatively small flow of oil to the combined fluid motor and pumping apparatus for providing a continuous supply of makeup oil thereto in a manner hereinafter described a drain conduit 30 is also connected to the apparatus for communicating any excessive oil flow to the tank 23 it should be noted that while only one combined fluid motor and pumping apparatus 10 has been depicted in the above described hydraulic implement and brake systems for illustrative purposes it is contemplated that two or more of such apparatus along with two or more brakes or sets of brakes be operatively connected in such systems the combined fluid motor and pumping apparatus 10 includes an elongated upright tubular housing 32 having an upper air cylinder or motor portion 33 and a lower oil cylinder or pumping portion 34 the motor portion is provided with a vertically disposed cylinder bore 36 having a predetermined diameter the opposite upper and lower ends of the motor portion are closed by a detachably mounted cover 37 and an end wall 38 respectively the.