[Olskuul]

These tuners are a PITA Bob. I've done a few of them.  There's a trick to reassembling them. First, insert the larger ball bearing into the hollow shaft, then add the spring and while depressing it in, insert the two smaller ball bearing in the side of the hollow shaft, making sure they're properly seated in the inner shaft. Hold those into position and slowly release the spring tension. The small bearings should lock in place. I usually add a bit of lithium grease to these pieces prior to assembly.