1. Check for the scratch on the interior surface of the housing caused by the gear.
2. If the scratch reaches more than half the area of the interior surface of the housing, replace at pump assembly.
3. Measure the housing I.D. where the interior surface is not scratched, and measure the housing I.D. where the interior surface is scratched.
4. If the valves obtained in the two determinations differ by more than the allowable limit, replace the hydraulic pump as a unit.
(Reference)
• Use a cylinder gauge to measure the housing I.D.
