I recently stripped and rebuilt my Garrett T2 turbo but on reassembling the turbo the shaft went tight and the vanes would not turn properly. I stripped it down and found a burr on the exhaust side of the turbo which had bend and squeezed the rear piston ring hence making it tight. There are plenty of videos showing you how to strip and rebuild your Garrett but none of them mention this...the solution, clean off the burr with wet and dry, replace the piston ring and hey presto.
