Rear Suspension System Buick LaCrosse I

Fastener Tightening Specifications

Fastener Tightening Specifications

Removal Procedure

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the tires and wheels. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the brake rotor. Refer to «Brake Rotor Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-replacement-rear-j65) in Disc Brakes.
4. Remove the ABS electrical connector from the wheel speed sensor (1), if equipped.
5. Remove the mounting bolts from the rear bearing/hub (4).
6. Remove the wheel bearing/hub (3) and the backing plate (2).

Installation Procedure

1. Install the backing plate (2) and the wheel bearing hub (3).
2. Install the wheel bearing/hub-to-knuckle bolts. Tighten: Tighten the bolts to 75 N.m (55 lb ft).
3. Install the ABS electrical connector to the wheel speed sensor (1), if equipped.
4. Install the brake rotor and caliper. Refer to «Brake Rotor Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-replacement-rear-j65) in Disc Brakes.
5. Install the tires and wheels. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
6. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the rear tires and wheels. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the exhaust pipe. Refer to «Muffler Replacement»(/buick/lacrosse/i-2004-2009/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
4. Disconnect the brake lines from the rear suspension support. Refer to «Brake Hose Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system) in Hydraulic Brakes.
5. Disconnect the parking brake cables and tensioner from the suspension support. Refer to «Park Brake Cable Replacement - Left Rear»(/buick/lacrosse/i-2004-2009/remont/parking-brake-system/#parking-brake) and «Park Brake Cable Replacement - Right Rear»(/buick/lacrosse/i-2004-2009/remont/parking-brake-system/#parking-brake) in Park Brake.
6. Remove the stabilizer shaft from the rear suspension support. Refer to «Stabilizer Shaft Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) . IMPORTANT: Support the rear suspension support with jack stands before removing the mounting bolts.
7. Remove the rear wheel spindle rod bolts from the knuckle.
8. Remove the rear suspension support mounting bolts.
9. Remove the rear suspension support.

1. Position the rear suspension support in place.
2. Install 2 locating pins in the suspension support alignment holes, one on each side of the suspension support.
3. Install the rear suspension support mounting bolts. Tighten: Tighten the bolts to 110 N.m (81 lb ft).
4. Remove the locating pins from the suspension support alignment holes.
5. Position the rear wheel spindle rod to the knuckle. Install the retaining bolts and nuts to the knuckle. Tighten: Tighten the bolts and nuts to 150 N.m (110 lb ft).
6. Install the stabilizer shaft to the rear suspension support. Refer to «Stabilizer Shaft Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
7. Connect the brake lines to the rear suspension support. Refer to «Brake Hose Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system) in Hydraulic Brakes.
8. Install the parking brake cables and the tensioner. Refer to «Park Brake Cable Replacement - Left Rear»(/buick/lacrosse/i-2004-2009/remont/parking-brake-system/#parking-brake) and «Park Brake Cable Replacement - Right Rear»(/buick/lacrosse/i-2004-2009/remont/parking-brake-system/#parking-brake) in Park Brake.
9. Install the exhaust pipe. Refer to «Muffler Replacement»(/buick/lacrosse/i-2004-2009/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
10. Install the Tires and Wheels. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
11. Lower the vehicle.
12. Adjust the rear wheel alignment. Refer to «Measuring Wheel Alignment»(/buick/lacrosse/i-2004-2009/remont/wheel-alignment/#wheel-alignment-system__measuring-wheel-alignment) in Wheel Alignment.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Scribe the strut to the knuckle.
4. Remove the bearing/hub assembly. Refer to «Wheel Bearing/Hub Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
5. Remove the rear wheel spindle rods from the knuckle. Refer to «Spindle Rod Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
6. Remove the trailing arm (2) from the knuckle (3). Refer to «Trailing Arm Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
7. Remove the rear strut to knuckle bolts (2) and the nuts (1). Refer to «Strut Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
8. Remove the knuckle (5) from the vehicle.

1. Install the knuckle to the vehicle.
2. Hand start the strut to knuckle bolts (2) and nuts (1). Do not tighten the nuts at this time.
3. Connect the rear suspension trailing arm (2) to the knuckle (3). Refer to «Trailing Arm Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
4. Connect the rear wheel spindle rods to the knuckle. Refer to «Spindle Rod Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
5. Install the bearing/hub assembly. Refer to «Wheel Bearing/Hub Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
6. Tighten the strut to knuckle bolts (2) and nuts (1). Tighten: Tighten bolts to 120 N.m (89 lb ft).
7. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
8. Lower the vehicle.
9. Inspect the rear wheel alignment, adjust if necessary. Refer to «Measuring Wheel Alignment»(/buick/lacrosse/i-2004-2009/remont/wheel-alignment/#wheel-alignment-system__measuring-wheel-alignment) in Wheel Alignment.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the tires and wheels. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the left and right stabilizer shaft link lower nuts from the stabilizer shaft links (1).
4. Remove the clamp bolts from the stabilizer shaft.
5. Remove the stabilizer shaft from the rear suspension support.

1. Install the stabilizer shaft to the rear suspension support.
2. Install the stabilizer shaft clamps and bolts. Do not tighten the bolts at this time.
3. Install the right and left stabilizer shaft link nuts (1) to the stabilizer shaft links (2). Tighten: Tighten the stabilizer shaft link nuts to 45 N.m (33 lb ft). Tighten the stabilizer shaft insulator bracket nuts to 51 N.m (38 lb ft).
4. Install the tires and wheels. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
5. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the stabilizer shaft bolt and clamp.
3. Remove the stabilizer shaft insulator (2) from the stabilizer shaft.

1. Install the stabilizer shaft insulator (2) to the stabilizer shaft.
2. Install the stabilizer shaft insulator bracket. Tighten: Tighten the bolt to 48 N.m (35 lb ft).
3. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the stabilizer shaft link nut from the stabilizer shaft link (1) and the stabilizer shaft (2).
3. Remove the stabilizer shaft link nut (1) from the stabilizer shaft link (2) and the strut.
4. Remove the stabilizer shaft link (2) from the vehicle.

1. Install the stabilizer shaft link (1) to the vehicle.
2. Connect the stabilizer shaft link (1) to the stabilizer shaft (2).
3. Install the stabilizer shaft link nut to the stabilizer shaft link (1) and the stabilizer shaft (2). Tighten: Tighten the nut to 50 N.m (37 lb ft).
4. Connect the stabilizer shaft link (2) to the strut.
5. Install the stabilizer shaft link nut (1) to the stabilizer shaft link (2) and the strut. Tighten: Tighten the nut to 52 N.m (38 lb ft).
6. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the bolt (6) and nu (2) from the trailing arm (3) and the knuckle (8).
3. Remove the nut (4) and bolt (7) from the trailing arm (3) and the trailing arm bracket.
4. Remove the trailing arm (3) from the vehicle.

1. Install the trailing arm (3) to the trailing arm bracket.
2. Install the bolt (7) and nut (4) to the trailing arm (3) and the trailing arm bracket. Tighten: Tighten the bolt and nut to 110 N.m (81 lb ft).
3. Install the trailing arm (3) to the knuckle (8).
4. Install the bolt (6) and nut (2) to the trailing arm (3) and the knuckle (8). Tighten: Tighten the nut to 240 N.m (177 lb ft).
5. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Lower the rear suspension support to gain clearance to the spindle rod to suspension support bolt. Refer to «Support Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
4. Remove the bolt (1 or 2) and nut from the spindle rod and the rear suspension support.
5. Remove the spindle rod to knuckle bolt and nut.
6. Remove the spindle rod (1) from the vehicle.

1. Install the spindle rod (1) to the vehicle.
2. Install the spindle rod (1) to the knuckle (3).
3. Install the spindle rod to knuckle bolt and nut. Do not tighten at this time.
4. Install the spindle rod (9-10) to the rear suspension support.
5. Install the bolt (1-2) and nut to the rear suspension support. Tighten: Tighten the bolt to 135 N.m (100 lb ft).
6. Install the rear suspension support. Refer to «Support Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) . Tighten: Tighten the bolt to 150 N.m (110 lb ft).
7. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
8. Lower the vehicle.
9. Adjust the wheel toe angle. Refer to «Wheel Alignment Specifications»(/buick/lacrosse/i-2004-2009/remont/wheel-alignment/#wheel-alignment-system__wheel-alignment-specifications) in Wheel Alignment.

Note. Care should be taken to avoid chipping or scratching the coating when handling the suspension coil spring. Damage to the coating can cause premature failure.

1. Remove the strut-to-body mount nuts.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
4. Remove the stabilizer shaft link from the strut. Refer to «Stabilizer Shaft Link Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
5. Scribe the strut to the knuckle.
6. Remove the strut to knuckle bolts.
7. Remove the strut from the vehicle.

Note. Care should be taken to avoid chipping or scratching the coating when handling the suspension coil spring. Damage to the coating can cause premature failure.

1. Install the strut into place.
2. Install the strut to knuckle bolts. Tighten: Tighten the strut to knuckle bolts and nuts to 120 N.m (89 lb ft).
3. Connect the stabilizer shaft link to the strut. Refer to «Stabilizer Shaft Link Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
4. Install the tire and wheel. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
5. Install strut to body mount nuts (1). Tighten: Tighten the strut to body mount nuts to 45 N.m (33 lb ft).
6. Lower the vehicle.
7. Adjust the rear wheel alignment. Refer to «Wheel Alignment Specifications»(/buick/lacrosse/i-2004-2009/remont/wheel-alignment/#wheel-alignment-system__wheel-alignment-specifications) in Wheel Alignment.

Suspension Strut Disposal

1. Clamp the strut in a vise horizontally with the rod (1) completely extended.
2. Drill a hole in the strut at the center of the end cap (3) using a 5 mm (3/16 in) drill bit. Gas or a gas/oil mixture will exhaust when the drill bit penetrates the strut. Use shop towels in order to contain the escaping oil.
3. Remove the strut from the vise.
4. Hold the strut over a drain pan vertically with the hole down.
5. Move the rod (1) in and out of the tube (2) to completely drain the oil from the strut.

Tools Required

1. J 42991 Strut Rod Nut Socket
2. J 45400 Strut Spring Compressor

Disassembly Procedure

1. Remove the strut from the vehicle. Refer to «Strut Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .
2. Install the strut (2) in the J 45400 (1).
3. Turn the spring compressor forcing screw (1) until the coil spring (2) is compressed.
4. Use a 45 TORX® socket in order to hold the strut shaft. Remove the upper strut mount nut by turning with J 42991 .
5. Remove the strut from the J 45400 .
6. Loosen the compressor forcing screw (1) until the upper strut mount and coil spring (2) may be removed.
7. Remove the upper strut mount and the coil spring from the J 45400 .

Assembly Procedure

1. Install the coil spring and upper strut mount to the J 45400 .
2. Turn the spring compressor forcing screw (1) until the coil spring is compressed.
3. Install the strut to the coil spring and upper strut mount.
4. Install the strut retaining nut. Using the J 42991 and a 45 TORX® socket, install the strut mount nut. Tighten: Tighten the strut mount nut to 75 N.m (55 lb ft).
5. Remove the strut from the J 45400 .
6. Install the strut to the vehicle. Refer to «Strut Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) .

J 6627-A Wheel Stud/Ball Joint Remover

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the brake caliper and bracket. Refer to «Brake Caliper Bracket Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-rear) in Disc Brakes.
4. Remove the rotor (3). Refer to «Brake Rotor Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-replacement-rear-j65) in Disc Brakes.
5. Use the J 6627-A (2) to extract the wheel hub bolt from the hub (1).
6. Clean the wheel hub flange and clean the rotor of any corrosion, metal chips or foreign material.

1. Install the replacement bolt (3) in the wheel hub.
2. Add enough washers (1) to draw the bolt into the hub.
3. Install the wheel nut (2) with the flat side to the washers. Tighten: Tighten the wheel nut until the wheel bolt head seats against the hub flange.
4. Back off the wheel nut.
5. Remove the washers.
6. Install the rotor. Refer to «Brake Rotor Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-replacement-rear-j65) in Disc Brakes.
7. Install the brake caliper and bracket. Refer to «Brake Caliper Bracket Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-rear) in Disc Brakes.
8. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
9. Lower the vehicle.

General Description

The rear suspension utilizes coil springs over struts and light weight aluminum knuckles. Each wheel is mounted to a tri-link independent suspension system. The 3 links are identified as the inverted U-channel trailing arm and the tubular front and rear rods.

Scheme 1

Parallel links allow the rear wheels to deflect upward when the rear wheels hit a road hazard, without moving the toe angle in a positive direction. An advantage of this suspension system is the reduction of unsprung and overall weight. Handling is improved with the independent action of each rear wheel. The rods control the lateral wheel deflection.

Several techniques are employed to achieve this independent wheel movement. The tri-link design may be compared to a right angle. The wheel is located at the right angle formed by the rods and the trailing arm. The ends of the tri-links hinge in order to provide vertical wheel travel. The solid links force the wheel to travel through a controlled arc whose fore-aft position is determined by the trailing arm and whose lateral position is determined by the rods.

Aside from maintaining geometric wheel location, each portion of the suspension has additional functions. The knuckle supports the brake caliper. All brake torque and braking forces are transmitted through the tri-links and the strut. The final duty of the rods is to maintain the camber angle of the wheel throughout the wheel's travel and to allow for setting the toe. The overall result of this rear suspension geometry is to maintain the rear wheels in a near vertical position at all times.

The stabilizer shaft attaches to the stabilizer bar drop link and extends rearward, where the stabilizer connects to the rear suspension support by 2 rubber bushings and mounting brackets.

A non-serviceable unit hub and bearing bolts to the knuckle. This hub and bearing is a sealed, maintenance-free unit.

Check the suspension system periodically for the following conditions

1. Shock absorbency
2. Bushing durability
3. Tightness of attaching bolts
4. Visible damage
5. Misalignment
6. Excessive wear

Special Tools

Special Tools Illustration Tool Number/Description J 42991 Strut Rod Nut Socket J 45400 Strut Spring Compressor J 6627-A Tie Rod Puller

Scheme 2

Scheme 3

See also:
• Lifting and Jacking the Vehicle
• Tire and Wheel Removal and Installation
• Brake Rotor Replacement - Rear (J65, JL9)
• Fastener Notice
• Muffler Replacement
• Brake Hose Replacement - Rear
• Park Brake Cable Replacement - Left Rear
• Measuring Wheel Alignment
• Wheel Alignment Specifications
• Brake Caliper Bracket Replacement - Rear (J65, JL9)
• Stabilizer Shaft Replacement