Power Steering General Servicing GMC Pickup R2500

TROUBLE SHOOTING

Refer to TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

TESTING

Note. On Astro and Safari, replace idler arm assembly if an up and down force of 25 ft. lbs. (110 N.m), applied at relay rod end of idler arm, produces a lash of more than 1/8" (3 mm) for a total of 1/4" (6 mm) in straight-ahead position.

PREPARATION

1. With belt tension correct, disconnect power steering pump pressure hose. See «BELT TENSION»(/gmc/pickup-r2500/1987-1989/remont/manual-power-steering/#power-steering-general-servicing) table. Keep hose end raised to prevent fluid loss. Connect pressure hose of gauge to power steering pump fitting. Connect other hose from valve side of tester to steering gear inlet.
2. Open valve. Run engine until fluid reaches normal operating temperature of 170°F (77°C). Check fluid level. Add fluid (if necessary).

BELT TENSION (1)

PRESSURE TEST

1. Note pressure reading with valve open and engine idling. Pressure should be 80-125 psi (5.6-8.8 kg/cm 2 ).
2. If pressure is above 200 psi (14.1 kg/cm 2 ), check hoses for restrictions and poppet valve (Saginaw gears) for proper assembly.
3. Close gate valve completely and reopen 3 times. Record highest reading each time. DO NOT close valve for more than 5 seconds. If pressure is less than specification, clean or replace flow control valve in pump. If pressures are still low, replace pump.
4. If readings are within specifications and within 50 psi (3.5 kg/cm 2 ) of each other, pump is operating properly. Refer to the «PRESSURE TEST SPECIFICATIONS»(/gmc/pickup-r2500/1987-1989/remont/manual-power-steering/#power-steering-general-servicing) table. If pressures are high, but do not repeat within 50 psi (3.5 kg/cm 2 ), flow control valve in pump is sticking. Remove flow control valve. Clean or replace flow control valve.
5. If pump is within specifications, open valve and turn steering wheel from right to left stops. Record pressure. DO NOT hold wheel against stops more than 5 seconds.
6. Pressure should be same as specified. Refer to the «PRESSURE TEST SPECIFICATIONS»(/gmc/pickup-r2500/1987-1989/remont/manual-power-steering/#power-steering-general-servicing) table. If pressure is low, steering gear is leaking internally and must be overhauled.
7. Turn steering wheel from left to right with engine idling at 600-800 RPM. See «PRESSURE TEST SPECIFICATIONS»(/gmc/pickup-r2500/1987-1989/remont/manual-power-steering/#power-steering-general-servicing) table.
8. If pressure is low, momentarily close valve. If pressure is less than specified, pump is faulty. If pressure is within specification but was low at previous reading, steering gear is faulty.

PRESSURE TEST SPECIFICATIONS

SERVICE INTERVALS

Check fluid at every oil change.

CHECKING FLUID LEVEL

Check fluid level with engine stopped and fluid hot or cold. Fluid level must be at "FULL-HOT" or "FULL-COLD" mark on dipstick. On models with remote reservoir, keep fluid level 0.5-1.0" from top of reservoir with wheels turned fully to left.

REFILLING & BLEEDING SYSTEM

1. Fill reservoir to correct level. See «RECOMMENDED FLUID»(/gmc/pickup-r2500/1987-1989/remont/manual-power-steering/#power-steering-general-servicing) table. Let oil settle for 2 minutes. Start engine and run for 4-5 seconds. Check reservoir. Add oil (if necessary). Repeat procedure until level in reservoir remains constant.
2. Raise front of vehicle so that both wheels are off ground. Start engine and increase engine speed to 1500 RPM. Turn wheels right and left, lightly contacting stops. Check fluid level. Add fluid (if necessary).
3. Lower vehicle. Turn wheels right and left. Check fluid level. Add fluid (if necessary). If oil is foamy, go to step 4).
4. Allow vehicle to stand for a few minutes with engine off. Repeat steps 1) through 3), with front of vehicle raised. Again check fluid level and for air in system. If level is low or there is air in system, repeat complete procedure.

RECOMMENDED FLUID

See also:
• BELT TENSION