HPI RS4 Differential Rebuild
It's time for another installation of the HPI Cuda rebuild. This weeks adventure delves into differential rebuilding. It's not all that hard, just look at the first photograph and all of those nice clean parts laid out. After a quick bath in the ultrasonic cleaner to remove old dirt and grime we are ready to reassemble. There was just one bitty problem as I started assembling things, I did not like the amount of backlash in the spider gears. It slid back and forth in the housing a whole lot more than I wanted. HPI used to make washers to set backlash but of course they are long gone so what to do? Brass shim stock to the rescue. I cut a strip, then squares and then trimmed off the corners. I used my old mechanical punch to stab holes in them and presto, everything fits better. The next problem was seals, HPI doesn't have any of those either. With a little research I realized ARRMA O-rings were just the perfect size to replace the worn out HPI seals. Remember this isn't a car you have to drive to work tomorrow so don't be afraid to experiment a little.