The pump housing was set up on the press so that there was clearance for die front shaft as it emerged through the housing as the bearing assembly is pushed through. Make sure that the bearing assembly is perpendicular as it starts to enter the housing and it will then go in smoothly. Once the outer garage door opener 24v sleeve is flush with the front of the housing, the bearing is in the correct position.
Attention now turns to the garage door opener 24v and the impellor. Originally the seal came in two pieces, consisting of a thrower and a seal but the replacement is a one-piece unit. This has to be pushed on to the shaft as it needs to be a tight fit, sealing the shaft, and once again the old gudgeon pin is the correct size for this task. It needs to be pushed on until the seal is home in its recess in the pump body.
A smear of RTV around the seal seat may be prudent, just in case corrosion has damaged the seat which could allow leakage. As the bearings emerge packing will be required between the garage door opener 24v body and the press. Under the gunge is the spacer that sets the distance between the two bearings. In my case I had to make a new one as the bearings were slightly thinner than the originals. The shaft now needs to be cleaned as it is reused with the new bearings.