This should help you.
The purpose of a MacPherson strut, much like a shock absorber, is to dampen harsh spring movement and provide a means of dissipating the motion of the wheels. As a result, shocks encountered by the wheels are not totally transmitted to the body and, therefore, to you and your passengers. As the wheel moves up and down, the strut shortens and lengthens, thereby imposing a restraint on movement by its hydraulic action.
A good way to see if your struts are functioning correctly is to push one corner of the car until it is moving up and down for almost the full suspension travel, then release it and watch its recovery. If the car bounces slightly about one more time and comes to a rest, the strut is all right. If the car continues to bounce excessively, the struts will probably require replacement.
REMOVAL & INSTALLATION
See Figures 1, 2, 3, 4, 5, 6 and 7
- Remove the top strut-to-body mounting nuts.
- Loosen the wheel nuts, then raise and support the vehicle on jackstands. Make sure the weight of the vehicle is not on the control arm.
Fig. Fig. 1: Exploded view of a MacPherson strut assembly
- Remove the wheel and tire assembly.
- Remove the brake line bracket from the strut assembly.
- Install the boot protector tool J-28712 (Double-Offset joint) or J-33162 (Tri-Pot joint) over the drive axle boot.
Fig. Fig. 2: Using a ratchet, remove the top strut-to-body mounting nuts
If equipped with a Tri-Pot joint, disconnect the drive axle from the transaxle before separating the strut from the steering knuckle.
- If equipped, separate the ABS front brake sensor connection. These are on the 6000 STE models.
- Before separating the strut from the steering knuckle, matchmark components by performing the following, as illustrated:
- Using a sharp tool, scribe the knuckle along the lower outboard strut radius.
- Scribe the strut flange on the inboard side, along the curve of the steering knuckle.
- Using a chisel, mark the strut-to-steering knuckle interface.
Fig. Fig. 3: Before removal, make scribe marks on the knuckle along the lower outboard strut radius (view A), the strut flange on the inboard side, along the curve of the steering knuckle (view B), and across the strut-to-steering knuckle interface (view C)
Fig. Fig. 4: Use a chisel to mark the strut-to-steering knuckle interface
- Remove the steering knuckle-to-strut bolts.
Fig. Fig. 5: With the use of two tools, remove the steering knuckle-to-strut bolts
The steering knuckle should be supported after removing the bolts to prevent axle joint overextension.
- Remove the strut.
Fig. Fig. 6: After removing the bolts connecting the steering knuckle to the strut, the strut can be extracted from the vehicle
Fig. Fig. 7: Pontiac 6000 STE AWD strut mounting is slightly different than that of front wheel drive models
- Install the strut to the body, then secure with the mounting nuts. Hand-tighten the nuts.
- Place a jack under the lower arm. Raise the arm and install the lower strut-to-knuckle bolts. Align the strut-to-steering knuckle marks made during removal. Tighten the strut-to-knuckle bolts to 122-140 ft. lbs. (165-190 Nm), and the strut-to-body nuts to 16-18 ft. lbs. (22-24 Nm).
- Reconnect the ABS sensor wiring.
- Install the brake hose bracket to the strut.
- Install the wheel, hand-tighten the lug nuts. Raise the vehicle slightly to allow removal of the jackstands.
- Remove the jackstands and lower the car. Tighten the lug nuts to 100 ft. lbs. (136 Nm).
If a new strut dampener has been installed, the front end will have to be realigned.
DISASSEMBLY & ASSEMBLY
See Figures 8 and 9
A MacPherson strut compressor tool J-34013-B or the equivalent must be used.
- Mount the compressor tool J-34013-B in the holder J-3289-20.
- Install the strut in the compressor J-34013-B, then install the compressor adapters, if used.
- Compress the spring approximately 1 / 2 its height after initial contact with the top cap. Do not bottom the spring or the dampener rod .
- Remove the nut from the strut dampener shaft and place the J-34013-27 on top of the dampener shaft. Using this alignment rod J-34013-27 guide the dampener shaft straight down through the bearing cap while decompressing the spring.
Fig. Fig. 8: Disassembly and assembly of the strut
- Remove the components.
- Install the bearing cap into J-34013-B if previously removed. Mount the strut into J-34013-B using the bottom locking pin only, then extend the dampener shaft and install J-34013-20 on the shaft.
Fig. Fig. 9: Special tools used by GM for suspension work
- Install the spring over the dampener and swing the assembly up so that the locking pin can be installed. Install the upper insulator, shield, bumper, and upper spring seat. Make sure that the flat on the upper spring seat is facing in the proper direction. The spring should seat flat at 10° forward of the centerline of the strut assembly spindle.
- Install tool J-34013-13 and turn, forcing the screw while J-34013-27 centers the assembly. When the threads on the dampener shaft are visible, remove tool J-34013-27, then install the nut.
- Tighten the nut, using a crow's foot line wrench while holding the dampener shaft with a socket.
- Remove tool J-34013-20.
REMOVAL & INSTALLATION
See Figures 1, 2 and 3
The following tools or equivalent will be needed to do this repair: J-33432 leaf spring compressor and J-37619 ball joint stud remover.
Fig. Fig. 1: A leaf spring compressor and ball joint stud remover are required for rear strut removal/installation
Fig. Fig. 2: The AWD rear suspension utilizes one leaf spring and two strut assemblies, rather than shock absorbers
- Loosen the lug nuts on the rear wheels.
- Open the deck lid and raise the vehicle securely.
- Remove the wheel and tire assembly, then remove the lug nuts.
- Support the lower control arm with a suitable stand or install the leaf spring compressor tool J-33432.
- Remove the outer toe link cotter pin and the castellated nut at the strut.
- Disconnect the toe link end from the lower strut mount assembly using tool J-37619.
- Remove the parking brake cable from the strut mount bracket and move it out of the way.
- Remove the bolts from the parking brake cable bracket and remove the bracket.
- Loosen and remove the lower strut mount bolts that attach to the spindle, make sure to retain the nut plate for installation.
- Disconnect the upper strut mount by removing the attaching bolts, then pull the strut assembly from the vehicle.
- Position the strut to the upper strut mounting flange, install the upper strut mounting bolts and hand-tighten them.
Fig. Fig. 3: Rear strut mounting on the AWD 6000 STE
- Position the lower strut mount to the spindle assembly. Position the nut plate into place, then install the 2 bolts into the lower strut mount assembly.
- Tighten the lower mount bolts to 148 ft. lbs. (200 Nm).
- Install the brake cable bracket to the lower strut mount and install the 2 attaching bolts. Connect the parking brake cable into the cable bracket.
- Install the toe link end to the lower strut mount assembly.
- Mount the castellated nut onto the outer toe link end at the lower strut mount, then tighten to 46 ft. lbs. (62 Nm).
- Insert a new cotter pin at the castellated nut, tighten the upper strut mount bolts to 40 ft. lbs. (54 Nm).
- Remove the leaf spring compression tool or stand supporting the control arm.
- Install the wheel and tire, hand-tighten the lug nuts.
- Lower the vehicle, tighten the lug nuts to 100 ft. lbs. (136 Nm). Close the deck lid.