Hints & Tips № 1 — Freeing a Tight Ball Thrust Bearing
Written by Frank Paine for our February 1995 Newsletter
Those of us lucky enough to chance upon a new or unused Ball Thrust Bearing (part № 168) may have found that some balls in the cage are stiff to rotate, due to being too tightly squeezed by the two halves of the cage (168c).
No amount of lubrication or rolling the balls in their housing seems to free them adequately, and if the bearing is used in this condition, it is stiff in use (which defeats the object of having a ball thrust bearing) and it damages the paintwork of the toothed and plain races.
The best way I have found to free the balls in their cage is as follows. Rest an individual ball on a hard surface (steel or similar), and with a thumb each side of the ball, press downwards on the cage quite firmly.
Freeing a tight ball thrust bearing
This will tend to increase the ‘bell-mouth’ of the upper half of the cage that retains the ball, and thus increase the clearance around it. The ball should now rotate freely.
Repeat the exercise with the other balls that are binding — but keep the cage the same way up each time — and voila! A free-spinning ball thrust bearing.