Turbocharger Repair - Shaft Play

Turbocharger shaft play is a term that applies to the actual shaft which runs between the intake and exhaust housings of a turbo. There are many types of turbochargers that each will have acceptable shaft play. Most turbo units are floating bearing turbos which means that the oil pressure is required to stabilize the shaft completely. This means that there will be a slight amount of shaft play in the unit when no oil pressure is present. Knowing the tolerances of these turbos is key to diagnosis. Ball bearing turbos will have no shaft play at all when they are in working order. Ball bearing turbos are not as common due to the high cost of the units. 

The tolerance for shaft play on a floating bearing turbo is enough that it can be seen but the blades of the unit will not touch the sidewall of the housing. If the blades of the impeller can touch the side with very little force then the unit should be replaced. That said if the blades are forced to touch the sidewall with excessive pressure then the turbocharger has just been damaged by the person doing this. Shaft play in an in and out fashion is never acceptable and means that internally there is serious damage to the turbocharger.