Checking the play....the buzz word....don't get me wrong...but everyone wants to check the play of the turbo shaft....
To check the play you need a lot of experience. Really a lot and it is so missleading....people grap the small shaft and yeahhh!!! There is play!!
First: Of course there is play and everytime you try it there is even more! Why? Because the shaft is in a floating bushing bearing and there are two layers of oil. The first layer is between the shaft and the floating bearing and the second is between the bearing and the housing. Everytime you're moving the shaft with your fingers you pump out the oil, increasing the (normal) play you can feel. If at all, you need to have and keep oil in the bearing to measure the play.
Second: You must be an expert with a lot of feeling in your finger tips to distinguish between axial and radial play. Who can really decide which play is felt when he isn't doing that every day (and after feeling it, dismantle teh turbo and see if one was really right!). The fingertips are soft and that makes it hard to feel which kind of play is present.
I work a lot on cars and engines and I visited Motair in Cologne, Germany, the largest turbo repair company in Europe (you can read about my visit here:
https://matsch-und-piste.de/der-turbolader-die-diva-des-motors-turboladerschaeden-vermeiden/ ). They made a blindtest with me. They asked me to try to find play at different turbos but they didn't say if it had too much play (damaged) or not. I failed every time. What they did and they explained it was, that they pushed some oil in the oil feed everytime they try to detect play. So if you really want to find play you have to take te turbo out, push oil in the oil feed and work very precisely with a lot of experience. Just grabing the shaft and try to move it, will not do it. Except it has already a large amount of play, but be sure, if that is the case you noticed the damage already by other indicators....
I assume countless turbos got replaced because "experts" felt play....
AWo