133 November 14, 1941 – Unnecessary Wheel Bearing Failures on Models 640 and 641
Care must be used when assembling the bearings into the· hubs to allow enough end play so that when the wheel is assembled into the frame and the center axle nuts ore tightened, the bearings do not bind.
After the wheel has boon completely assembled in the machine, it should be checked to see that it turns freely and if it binds, the wheel should be removed and the hollow axle nut backed off to give more bearing clearance.
If the bearings are too tight, they will not allow enough clearance for grease and a dry roller surface will result. This dry roller surface will cause a chipping of the tapered rollers and roughening of the bearing race surfaces, although the hubs may be well greased in assembly, bearing failure can result under these conditions.
Tightening of the center axle changes the clearance of the bearing cones due to the thread play between the hollow axle and the hollow axle nut. In other words, the hollow axle assembly may be fitted into the wheel freely before the complete assembly of the wheel has been made and by drawing up on the center axle it will change the cone adjustment.
When greasing a hub and bearings in assembly, each part should be well coated with grease. Often times hubs are filled with grease and parts assembled. The pushing thru of the hollow axle will remove the grease from one side of the hub. It is therefore very essential that hubs are well packed from both sides and each bearing cone packed with grease before assembly.
A check should be made on all wheels to see that the bearings are free and that they are properly packed with grease which will eliminate bearing failures.