the side plates it can be seen from fig3 that the discharge pressure is communicated to this region behind the shoes as limited by the seals 26 and the seals in the side sections and acts to press the shoes against the edges of the side plates and into sealing relationship with the tips of the teeth preferably the shoes are dimensioned when initially made so that when the pump is finally assembled the gears track into the shoes slightly cutting their final clearance and thus assuring a good seal between the teeth and the shoes the discharge pressure is also communicated to the backs of the side plates within the confines of seal 28 the pressure balance on the plates being such that a seal is maintained with the sides of the teeth despite wear at the interfaces of the plates and the teeth preferably the side plates have champhered portions 29 which are located adjacent to and in position so that they slightly overlap the shoes these portions serve to provide a more gradual less abrupt buildup of pressure as the teeth pass into sealing relationship with the shoes as should be evident from the above the function of the shoes is to provide a fluid seal with the tips of those teeth 10a and 11a in the limited region immediately adjacent the high pressure side of the gears which in the case of the pump is the outlet 21 as is shown in.