Hydraulic System

NOTE: If pressure is less than 1100 psi (77.5 kg/cm² ) at idle but increases with engine speed, problem is either a defective pump control valve or internal leakage in rack and pinion.

Connect a 1500 psi (100 kg/cm² ) pressure gauge to power steering pump pressure line. See Fig 1. Start engine, and let it idle. Turn steering to full lock. Exert pressure on steering gear. Pressure should be 1100-1200 psi (77.5-84.4 kg/cm² ).

Fig 1: Connecting Pressure Gauge & Shutoff Valve
Courtesy of JAGUAR CARS, INC.
If system pressure readings were not to specification, connect Shutoff Valve (JD10-2) between pump and pressure gauge. This will isolate steering pump from steering gear and determine if problem is in gear or in pump. See Fig 1.
CAUTION: DO NOT keep shutoff valve closed for more than 5 seconds at a time, otherwise fluid will overheat, causing possible damage to system.
With shutoff valve open, start engine and allow steering fluid to reach normal operating temperature. Close shutoff valve. Repeat pressure tests.
If pressure is 1100-1200 psi (77-84 kg/cm² ), fault is in steering gear. If pressure is not as specified, fault is in pump. See OVERHAUL.