TUBE A 0349345 - Caterpillar

Introduction
Any method of instrument testing of the performance of the diverter valve or the pump of the supplemental system, when installed on a machine, is difficult.For a practical test, do these steps:1. Find a safe, clear area.2. While the machine is moving in a forward direction, put the transmission in the NEUTRAL position and shut the engine off.3. As the machine moves, make an estimate of the performance of the supplemental steering system. The difference in capacity between the supplemental pump and the steering pump must be used as a basis for the estimate.For example, on the 966C Wheel Loader, the output of the supplemental pump is 17 U.S. gpm (64,3 lit/min) at 12 mph. The output of the standard steering pump is 40 U.S. gpm (151,4 lit/min) at 2200 rpm of the engine (full load rpm).4. Do Steps 2 and 3 with the machine moving in the reverse direction.If performance is not good enough, remove the diverter valve and inspect for spools that are not free. Remove the supplemental pump and inspect for wear and leakage by the seals.