The problem stems from the fact that the leather inner grease seals are press fit into the bearing race. The spindle also has a unique taper. The new roller bearings in the kits are custom specified and not readily available from a bearing supplier. They also use neoprene instead of leather. There is really nothing inherantly wrong with the ball bearings if you keep them greased and adjusted and don't run really wide tires with power steering. You can wear out at least two sets of ball bearings before you will recover the cost of the roller bearing set, at which point the rest of the truck will be worn out and so will the roller bearings.

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