On the 5 ton Robert Hudson bottom discharge hopper the phosphor bronze bush on the release mechanism became loose in the housing due to the impact it was subjected to.

This application is not lubricated so the choice of alternative materials is limited. Some synthetic materials tested squeezed out, and were thus found to be unsuitable.

The phosphor bronze bush was replaced with a Vesconite bush (OD 84 mm x ID 65 mm - 30 mm long)(OD 3.3" x ID 2.5" - 1.2" long). This has lasted substantially longer than the original phosphor bronze.