POWER STEERING SHUDDER (INSTALL HIGH EXPANSION HOSE)

SUBJECT: POWER STEERING SHUDDER (INSTALL A "TUNED" OR HIGH EXPANSION HOSE)

MODELS AFFECTED: 1989-91 SKYLARK WITH 2.5L (VIN (U) ENGINE 1990 SKYLARK WITH 2.3L CODE D QUAD 4 ENGINE 1989-90 SKYLARK WITH 3300 (VIN N) ENGINE

CONDITION:

----------- Customers may comment about a shudder, moan or vibration that occurs when turning the steering wheel under the following conditions:

- Vehicle stopped with brake applied (or moving very slowly) - Vehicle in gear - Engine at idle speed

The shudder or moan may occur during parking maneuvers or other situations when the steering wheel is turned while the vehicle is stopped or moving very slowly. It is also sensitive to steering wheel rotational speed as well as engine speed. The shudder is commonly more severe during hot ambient temperatures.

CAUSE:

------ A combination of steering gear valve instability and/or engine firing pulses generating a disturbance that is transmitted through the body structure.

CORRECTION:

----------- Install a "tuned" power steering return hose and/or high expansion pressure hose between the steering pump and gear.

1990 Skylark with 2.3L (VIN D) engine

Starting with the following VIN breakpoints 1990 vehicles are equipped with a "tuned" return hose which should reduce or eliminate the shudder condition.

"TUNED" RETURN HOSE

Lansing LM017241

Starting with the following VIN breakpoints, 1990 vehicles are also equipped with a new high expansion pressure hose which further reduces the shudder condition:

NEW PRESSURE HOSE

Lansing LM045756

Vehicles built BEFORE the above listed "TUNED RETURN HOSE" breakpoints, the shudder condition may be repaired by installing a "tuned" return hose, P/N 26023904. In a very limited number of cases, the tuned return hose may not completely eliminate the shudder condition. In these cases, the condition may be repaired by installing a new high expansion pressure hose, P/N 26024244 (and removal of the clip from the power steering pump).

Vehicles built ON OR FOLLOWING the above listed "TUNED RETURN HOSE" VIN breakpoints, but before the above listed "NEW PRESSURE HOSE" VIN breakpoints, are equipped with tuned return hoses, but are not equipped with new high expansion pressure hoses. For vehicles in this range that still exhibit some power steering shudder, the condition may be repaired by installing a new high expansion hose, P/N 26024244 (and removal of the clip from the power steering pump).

Vehicles built after the above listed "NEW PRESSURE HOSE" VIN breakpoints are equipped with a "tuned" return hose and a new high expansion pressure hose and should not exhibit the shudder condition.

1989-90 Skylark with 3300 (VIN N) engine

Starting with the following 1990 VIN breakpoints, vehicles are equipped with a new high expansion pressure hose which corrects this condition:

Lansing LM075954

In vehicles built before these VIN breakpoints, this condition may be repaired by installing a new high expansion pressure hose, P/N 26026183.

1990-91 Skylark with 2.5L (VIN U) engine ---------------------------------------- Starting with the following VIN breakpoints, 1991 vehicles are being built with a new "tuned" return hose which corrects this condition;

Lansing MM215410

In vehicles built before these VIN breakpoints, this condition may be repaired by installing a new "tuned" return hose, P/N 26027298.

Vehicles with tuned return hoses that still exhibit steering shudder, install a high expansion pressure hose, P/N 26027234.

Note: If the above hoses do not repair the shudder condition, please contact Technical Assistance.

Parts are currently available from GMSPO.

Use currently available labor operation and time.

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.