POWER STEERING SHUDDER (INSTALL HIGH EXPANSION HOSE). Chevrolet Beretta 1990

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

VEHICLES AFFECTED: 1989-91 "J/L/N" W/3.1, 2.3, 2.5, 2.2, 2.0, 2.8, 3300

This bulletin supersedes and cancels Product Service Bulletins #90-3-112 and #90-3-136.

MODELS/YEARS: ------------- 1991 "J" w/3.1L (VIN T) engine - (Pontiac) 1990 "N" w/2.3L (VIN D or A) engine - (Pontiac) 1989-91 "N" w/2.5L (VIN U) engine - (Pontiac) 1989-91 "N" w/2.5L (VIN U) engine - (Oldsmobile) 1990 "N" w/2.3L (VIN D or A) engine - (Oldsmobile) 1989-90 "N" w/3.3L (VIN N) engine - (Oldsmobile)

1989-91 "N" w/2.5L (VIN U) engine - (Buick) 1990 "N" w/2.3L (VIN D or A) engine - (Buick) 1989-90 "N" w/3.3L (VIN N) engine - (Buick)

1990-91 "J" and "L" w/2.2L (VIN G) engine - (Chevrolet) 1990-91 "J" and "L" w/3.lL (VIN T) engine - (Chevrolet) 1990 "L" w/2.3L (VIN A) engine - (Chevrolet) 1989 "J" and "L" w/2.OL (VIN 1) engine - (Chevrolet) 1989 "J" and "L" w.2.8L (VIN W) engine - (Chevrolet)

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 "J" w/2.2L (VIN G) engine - (Chevrolet) 1989 "J" w/2.0L (VIN 1) engine - (Chevrolet)

This condition may be repaired by installing a "tuned" return hose, P/N 26025260.

J-cars built during the 1990-1991 model year already have the "tuned" return hose. A 1990-91 "J" car will require a high expansion pressure hose, P/N 26029284 to repair the shudder.

1990-91 "J" w/3.1L (VIN T) engine - (1990-91 Chevrolet/Pontiac) 1989 "J" w/2.8L (VIN W) engine - (Chevrolet) ---------------------------------------------------------------- Starting with the following VIN breakpoints, 1991 model vehicles are being built with a new high expansion pressure hose which corrects this condition. Vehicles built BEFORE the VIN breakpoints listed below may be repaired by installing a new high expansion pressure hose, P/N 26026623.

Chevrolet (Lordstown) M7117613 Pontiac (Lordstown) M7526173

1990-91 "L" w/2.2L (VIN G) engine - (Chevrolet) 1989 "L" w/ 2.0L (VIN 1) engine - (Chevrolet) ------------------------------------------------ This condition may be repaired in 1989 "L" cars by installing a tuned return hose, P/N 26006690.

"L" cars built during the 1990-91 model year already have the tuned return hose. A 1990-91 "L" car will require a high expansion pressure hose, P/N 26029284 to repair the steering shudder.

1990 - 91 "L" w/3.1L (VIN T) engine - (Chevrolet) 1989 "L" w/2.8L (VIN W) engine - (Chevrolet) -------------------------------------------------- Starting with the following VIN breakpoints, 1991 model vehicles are being built with a new high expansion pressure hose which repairs this condition. Vehicles built before the VIN breakpoints listed below may be repaired by installing a new high pressure expansion hose, P/N 26028229.

Chevrolet (Linden) ME178914 Chevrolet (Wilmington) MY219301

1990 "L" w/2.3L (VIN A) engine - (Chevrolet) -------------------------------------------- Starting with the following VIN breakpoint, 1990 vehicles are equipped with a "tuned" return hose which helps this condition. Vehicles built before this VIN breakpoint, may be repaired by installing a new "tuned" return hose, P/N 26024663.

Chevrolet (Wilmington) LY223211

1990 "N" w/2.3L (VIN D or A) engine - (Buick/Oldsmobile/Pontiac) ---------------------------------------------------------------- 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

Oldsmobile (Lansing (A)) LM717359 Buick (Lansing (A)) LM017241 Pontiac (Lansing (B)) LC252285

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

Oldsmobile (Lansing (A)) LM744715 Buick (Lansing (A)) LM045756 Pontiac (Lansing (B)) LC305247

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 "N" w/3.3L (VIN N) engine - (Buick/Oldsmobile) ------------------------------------------------------- Starting with the following 1990 VIN breakpoints, vehicles are equipped with a new high expansion pressure hose which corrects this condition:

Oldsmobile (Lansing (A)) LM778565

Buick (Lansing (A)) 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 "N" w/2.5L (VIN U) engine - (Buick/Oldsmobile/Pontiac) --------------------------------------------------------------- Starting with the following VIN breakpoints, 1991 vehicles are being built with a new "tuned" return hose which corrects this condition;

Oldsmobile (Lansing (A)) MM016754 Buick (Lansing (A)) MM215410 Pontiac (Lansing (A)) MC541388

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.

CHEVROLET

ENGINE CARLINE VIN MODEL HOSE PART MODEL YEAR/ (NOTE) ENGINE CODE YEAR TYPE NUMBER VIN BREAKPOINT ---- -------- ----- ------- ------------- -------- --------------- J(2) 2.0L/2.2L 1/G 1989-90 TUNED RETURN 26025260 SORP 1991 J(1) 2.0L/2.2L 1/G 1990-91 HIGH EXPANSION 26029284 SERVICE ONLY J(2) 2.8L/3.1L W or T 1989-91 HIGH EXPANSION 26026623 1991-M7117613 L(2) 2.0L/2.2L 1/G 1989-90 TUNED RETURN 26006690 SORP 1991 L(3) 2.2L LM3 G 1990-91 HIGH EXPANSION 25029284 SERVICE ONLY L(2) 2.8L/3.1L W or T 1989-91 HIGH EXPANSION 26028229 ME178914/MY219301 L(2) 2.3L LGO A 1990 TUNED RETURN 26024663 1990-LY223211

NOTE: ------ 1 USE RETURN HOSE P/N 26025260 BEFORE TRYING THIS NEW PRESSURE HOSE. 2 VEHICLES BUILT AFTER THIS BREAKPOINT ALREADY CONTAIN THIS HOSE. 3 USE RETURN HOSE P/N 26006690 ON 1990 VEHICLES BEFORE TRYING THIS NEW PRESSURE HOSE. IF THE HOSES LISTED ABOVE DO NOT WORK PLEASE CONTACT TECHNICAL ASSISTANCE

PONTIAC

ENGINE CARLINE VIN MODEL HOSE PART MODEL YEAR/ (NOTE) ENGINE CODE YEAR TYPE NUMBER VIN BREAKPOINT ---- -------- ----- ------- ------------- -------- --------------- J(2) 3.1L LHO T 1991 HIGH EXPANSION 26026623 1991 M7526173 N(2) 2.3L D or A 1990 TUNED RETURN 26023904 1990 LC252285 LD2/LGO N(1,2) 2.3L D or A 1990 HIGH EXPANSION 26024244 1990 LC305247 LD2/LGO N(2) 2.5L L68 U 1989-91 TUNED RETURN 26027298 1991 MC541388 N(3) 2.5L L68 U 1989-91 HIGH EXPANSION 26027234 SERVICE ONLY

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.

BUICK

ENGINE CARLINE VIN MODEL HOSE PART MODEL YEAR/ (NOTE) ENGINE CODE YEAR TYPE NUMBER VIN BREAKPOINT ---- -------- ----- ------- ------------- -------- --------------- N(2) 2.3L D or A 1990 TUNED RETURN 26023904 1990-LM017241 LD2/LGO N(1,2) 2.3L D or A 1990 HIGH EXPANSION 26024244 1990-LM045756 LD2/LGO N(2) 3.3L LG7 N 1989-90 HIGH EXPANSION 26026183 1990-LM075954 N(2) 2.5L L68 U 1989-91 TUNED RETURN 26027298 1991-MM215410 N(30 2.5L L68 U 1989-91 HIGH EXPANSION 26027234 SERVICE ONLY

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

OLDSMOBILE

ENGINE CARLINE VIN MODEL HOSE PART MODEL YEAR/ (NOTE) ENGINE CODE YEAR TYPE NUMBER VIN BREAKPOINT ---- -------- ----- ------- ------------- -------- --------------- N(2) 2.3L D or A 1990 TUNED RETURN 26023904 1990-LM717359 LD2/LGO N(1,2) 2.3L D or A 1990 HIGH EXPANSION 26024244 1990-LM744715 LD2/LGO N(2) 3.3L LG7 N 1989-90 HIGH EXPANSION 26026183 1990-LM778565 N(2) 2.5L L68 U 1989-91 TUNED RETURN 26027298 1991-MM016754 N(3) 2.5L L68 U 1989-91 HIGH EXPANSION 26027234 SERVICE ONLY

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.

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.