In setting side bearing preload, what are the parts shown in Figure 3-19 used for?

The parts shown in the referenced figure play a critical role in the adjustment of both side bearing preload and drive pinion preload in a vehicle's rear axle assembly.

Setting side bearing preload is essential to ensure there's no excessive play between the bearings and the carrier, which supports the axle shafts. This preload allows for smoother operation and prolonged bearing life by ensuring that there is constant contact under load. Additionally, having the proper drive pinion preload is crucial to maintain gear mesh and alignment, which prevents premature wear and noise in the differential.

Utilizing the components depicted in the figure, technicians can accurately measure and adjust the preload on these bearings. They often have specific indicators or mechanisms that allow for precise adjustments to achieve the manufacturer's specifications.

This combined functionality enhances overall performance and durability, making the adjustment of both side bearing and drive pinion preload integral to differential servicing and maintenance. Therefore, the roles of these parts are not limited to just one aspect of preload adjustment but serve both purposes effectively.