PWR.STG.MOAN/SHUDDER REPL. INLET HOSE & CONTROL VALVE

SUBJECT: POWER STEERING MOAN/SHUDDER (REPLACE INLET HOSE, FLOW CONTROL VALVE AND SHIELD ALTERATION)

VEHICLES AFFECTED: 1990-91 BUICK W-CAR WITH 3.8L

This bulletin cancels Product Service bulletin 91-3-102, entitled "Power Steering Moan". Information contained in this bulletin will address both power steering moan and shudder, provide new part numbers and revised service procedure for correction of condition based on vehicle model year.

Condition:

----------- Some 1990-91 Buick W-cars with 3.8L V6 engines (RPO L27) and assembled prior to VIN breakpoint indicated below may exhibit a slight power steering moan/shudder condition noted during static or low speed turning maneuvers. This condition may be perceived as a disturbance the body structure and steering wheel.

VIN Breakpoint

Buick M1858118

Cause:

A combination of power steering pump pressure pulses and engine firing frequency generating a disturbance transmitted through the body structure.

Correction: 1990 vehicles -------------------------- Replace existing power steering inlet (pressure) hose and pipe assembly, pump flow control valve and alter heat shield following applicable Service Manual procedures, Product Service Bulletin 91-3-124, dated May 15/91 and noted in Figures 1 and 2.

Parts Required

P/N 26028655 Inlet Hose and Pipe Asm. P/N 7841852 Pump Flow Control Valve

1991 Vehicles

Replace existing power steering inlet (pressure) hose and pipe assembly and alter heat shield following applicable Service Manual procedures, Product Service Bulletin #91-3-124 and noted in Figures 1 and 2.

Parts Required

P/N 26028655 Inlet Hose and Pipe Asm.

Hose Installation sequence

1. Install hose and hand tighten fitting at pump.

2. Position to achieve light touch condition between foam sleeve and oil filter adapter (see point 'A' on figure).

3. Torque pump hose fitting to 27 N.m (20ft lbs) maintaining hose position noted in step 2.

4. Hand tighten fitting at power steering gear.

5. Install clamp on steering gear.

6. Torque steering gear hose fitting to 27 N.m (20ft lbs)

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.