A submersible well pump assembly includes a seal unit coupled between a pump and a motor. The seal unit has a forward guide member, a rearward guide member, and a labyrinth disc chamber connected between. The labyrinth disc chamber has an outer wall, a concentric guide tube and a number of axially spaced apart discs extending between the guide tube and the outer wall, defining cavities between the discs. Disc ports extend through the discs to communicate fluid between the cavities, the ports being at multiple angular locations relative to each other. A drive shaft extends through the guide tube, the forward guide member bore and the rearward guide member. The outer wall, the guide tube and the discs are made of a single-piece member.