So i just got my garret t25 used in the mail yesterday and check for shaft play, how can you tell when a turbo NEEDS to be rebuilt? Theres a tiny bit, i havent put a dial indicator on it or anything to see exactly how much. But the wheels both spin just fine and dont hit the walls. This is a non ball bearing, internally wastegated turbo. I was going to rebuild it, but ordered the wrong kit, so its kind of a hassle now.. im still pretty new to all this stuff, so bare with me!

 

journal bearing turbos will have some shaft play. once oil pressure is applied to the bearings most of the shaft play will go away.

 

just FYI you cant spin it fast enough by hand to determine when/if it will hit the sides.

When i tore my T76 off my last car it had very minor play but failed around 4500rpms when testing.

 

I'm by no means an expert, actually I know very little from working in a diesel shop. But I would think those turbos can relate to automotive's. To my understanding some play side to side is acceptable it is the up and down play that is bad. Someone correct me if I'm wrong though.

 

you have it reversed. up and down shaft play is normal. there should be minimal to no front to back shaft play.