Power Steering General Servicing GMC Cab & Chassis R3500

TROUBLE SHOOTING

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

IDLER ARM - ASTRO & 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. Keep hose end raised to prevent fluid loss. Connect Pressure Gauge (J-5176-D) hose 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 150-170°F (65-77°C). Check fluid level. Add fluid (if necessary).

PRESSURE TEST

1. Note pressure reading with valve open and engine idling. Pressure should be 80-125 psi (6-9 kg/cm 2 ). If pressure is above 200 psi (14 kg/cm 2 ), check hoses for restrictions and poppet valve for proper assembly.
2. Close gate valve completely and reopen 3 times. Record highest reading each time. DO NOT close valve for more than 5 seconds. Reading should be within specification. On R/V, G and P models (Scheme 1) On all other models, see PRESSURE TEST SPECIFICATIONS table.
3. If readings are within specification and within 50 psi (4 kg/cm 2 ) of each other, pump is operating properly. On R/V, G and P models (Scheme 1) On all other models, see PRESSURE TEST SPECIFICATIONS table.
4. If pressures are high, but do not repeat within 50 psi (4 kg/cm 2 ), flow control valve in pump is sticking. Remove flow control valve. Clean or replace flow control valve.
5. If pressure is constant but more than 100 psi (7 kg/cm 2 ) less than specification, clean or replace flow control valve in pump. If pressures are still low, replace pump.
6. If pump is within specification, open valve and turn steering wheel from right to left stops. Record pressure. DO NOT hold wheel against stops more than 5 seconds.
7. Pressure should be within specification. On R/V, G and P models (Scheme 1) On all other models, see PRESSURE TEST SPECIFICATIONS table. If pressure is low, steering gear is leaking internally and must be repaired.

Scheme 1

SERVICE INTERVALS

Check fluid at every oil change.

CHECKING FLUID LEVEL

Check fluid 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, fluid level must be .5-1.0" from top of reservoir with wheels turned fully to left.

RECOMMENDED FLUID

REFILLING & BLEEDING SYSTEM

1. Fill reservoir to correct level. 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 vehicle with both front wheels 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, proceed to step 4).
4. Turn off engine and let vehicle sit for a few minutes. Repeat steps 1) through 3) with wheels off ground. Check fluid for air in system. If fluid level is low and air is apparent, repeat complete procedure.

BELT TENSION (Tension in Lbs. Using Burroughs Tension Gauge)

TEST SPECIFICATIONS

PRESSURE TEST SPECIFICATIONS