Hydraulic System

Connect a 1500 psi (100 kg/cm² ) pressure gauge to pump pressure line, start engine and allow to idle.
Turn steering to full lock and exert pressure on steering gear. Pressure should be 1100-1200 psi (77.5-84.4 kg/cm² ) at idle.
NOTE: If pressure is below 1100 psi (77.5 kg/cm² ) at idle, but rises with engine speed increase, problem is either a defective pump control valve or internal leakage in rack and pinion.
If system pressure readings were not to specifications, connect a Shut-Off Valve (JD. 10-2) between pump and pressure gauge. This will isolate steering pump from steering gear and determine if problem is in gear or pump. See Fig 1.
With shut-off valve open, start engine and allow steering fluid to reach normal operating temperature. Close shut-off valve and repeat pressure tests.
NOTE: DO NOT keep shut-off valve closed for more than 5 seconds at a time, otherwise fluid will overheat and damage to system could occur.
If test pressures are not to specifications, fault is in steering gear. If test pressures are still not to specifications, fault is in pump. See OVERHAUL in this article.

Fig 1: Pressure Gauge and Shut-Off Valve Connections. By adding a shut-off valve, pump may be isolated from steering gear.