[Tommy]

First off, all I know about this is what I can glean from looking at your photos, so consider this an educated guess at best. If the item you describe as a spacer is connected to the steering rod with a set screw or the like, then it may be pressing against the pillow bearing as the rod expands its length when heated. The greatest movement in a heated object will be along its length. If both ends of the steering rod are anchored so it can't move along its length, then it will press against that bearing when heated.