As I am designing a new jet, and wanted it as simple as possible, specially fast change of impeller, I opened my SSS motor today to check if it is possible to fit a thrust bearing inside.
As my bearing was 9mm wide, But the brass distance only had 7mm I needed to machine the aluminium spacer a little. I tried to take it of, but it is glued. The screw are machined a little , but can not fall out. The rear shield has a 0,5mm high rib around the bearing, so the second part of bearing has perfect seat.
I think there are thrust bearings availible with only 5,5-6mm height. Then it should be possible without machining.