The bearings of the submersible pump withstand the weight of the impeller, as well as radial and axial forces during pump operation. Once the bearings are damaged, the pump's sealing and impeller mouth ring fail quickly. Small-power submersible pumps often use two rolling bearings, with the lower bearing also serving as a thrust bearing; medium-power submersible pumps use a combination of rolling and thrust bearings at the bottom; and high-power submersible pumps may even employ cylindrical roller bearings and a pair of cone roller bearings to bear radial and axial forces. The lower bearing and shaft should generally be locked to prevent axial movement of the main shaft during pump operation.
Submersible water-filled pumps commonly use guide bearings, made of tin bronze or phenolic plastic. The inner surface features grooves, allowing water flow to dissipate the heat generated by the bearings.