Power Steering - Shudder/Vibration/Moan
91pontiac15
Bulletin Number: 91-3-21
Reference Number: 133209
Publish Date: 10/91
Subject: POWER STEERING SHUDDER (INSTALL A "TUNED" OR HIGH EXPANSION HOSE)
Models
Affected: 1989-91 SUNBIRD AND GRAND AM MODELS W/3.1, 2.3, AND 2.5, ENGINES
This bulletin cancels and replaces bulletin 90-3-9B issued 8/90. Please discard bulletin 90-3-9B.
MODELS/YEARS:
1991 Sunbird models w/3.1L (VIN T) Engirle
1990 Grand Am models w/2.3L (VIN D or A) Engine
1989-91 Grand Am models w/2.5L (VIN U) 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.
1990-91 Sunbird models w/3.1L (VIN T) Engine
Starting with the VIN breakpoint (Lordstown) M7526173, 1991 model vehicles were built with a new high expansion pressure hose which corrects this condition. Vehicles built BEFORE the VIN breakpoint listed may be repaired by installing a new high expansion pressure hose, P/N 26026623.
1990 Grand Am models w/2.3L (VIN D or A) Engine
Starting with the following VIN breakpoint, 1990 vehicles are also equipped with a new "tuned" return hose which further reduces the shudder condition:
"TUNED" RETURN HOSE
(Lansing B) LC252285
Starting with the following VIN breakpoint, 1990 vehicles are also equipped with a new high expansion pressure hose which further reduces the shudder condition:
NEW PRESSURE HOSE
(Lansing B) LC305247
On vehicles built BEFORE the above listed "TUNED RETURN HOSE" breakpoint, 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.
1990-91 Grand Am model w/2.5L (VIN U) Engine
Starting with the following VIN breakpoint, 1991 vehicles are being built with a new "tuned" return hose which corrects this condition;
(Lansing B) MC541388
In vehicles built before this VIN breakpoint, this condition may be repaired by installing a new "tuned" return hose, P/N 26027298.
To repair 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.
Labor Operation Number : Pressure Hose E8622
Labor Time : See Current Labor Time Guide
Trouble Code : 92
Labor Operation Number : Return Hose E8623
Labor Time : See Current Labor Time Guide
Trouble Code : 92
ENGINE VIN MODEL YEAR/
CARLINE ENGINE CODE MODEL YEAR HOSE TYPE PART NUMBER VIN BREAKPOINT NOTE
J 3.1L LH0 T 1991 HIGH EXPANSION 26026623 1991-M7526173 2
N 2.3L LD2/LG0 D or A 1990 TUNED RETURN 26023904 1990-LC252285 2
N 2.3L LD2/LG0 D or A 1990 HIGH EXPANSION 26024244 1990-LC305247 1,2
N 2.5L L68 U 1989-1991 TUNED RETURN 26027298 1991-MC541388 2
N 2.5L L68 U 1989-1991 HIGH EXPANSION 26027234 SERVICE ONLY 3
NOTE:
1 USE RETURN HOSE P/N 26023904 BEFORE INSTALLING THIS NEW PRESSURE HOSE. REMOVE P/S PUMP HOSE CLIP.
2 VEHICLES BUILT AFTER THIS BREAKPOINT ALREADY CONTAIN THIS HOSE.
3 USE RETURN HOSE P/N 26027298 BEFORE INSTALLING THIS NEW PRESSURE HOSE.
IF THE HOSES LISTED ABOVE DO NOT WORK PLEASE CONTACT TECHNICAL ASSISTANCE.