How do i replace front wheel bearings on a 1991 subaru lyale 4wd wagon ?

SOURCE: replace front wheel bearings

The bearings in your car are pressed into a hub. If the part is available as an assembly, it can be replaced that way. Generally on a front drive car:
Remove wheels and brake calipers
If it is pressed in: remove the rotors, disconnect the drive shafts and remove the steering knuckle. Then the old bearing is pressed out and the new one pressed in with a machine shop press. If the bearing is part of the hub, that will be unbolted and the new one swapped.

On a scale of 1-10 difficulty, Id rate it a strong 7

SOURCE: how to replace front wheel

I can tell you on a 93 Altima that you have remove the entire wheel knuckle and press it out from the rear. Yeah, the knuckle, remove the strut tower bolts, drive train ( which can be lighty pressed out ), caliper and bracket, and remove the ball joint. There's a snap ring at the back of the wheel knuckle that holds the bearing, then press it out with a socket and a table vice or something to that effect. By the way the going commercial rate if you take it to a shop and have them do it starts at $150 for labor. Worth it, oh yeah.

SOURCE: Replacing front wheel bearing

The brake rotor needs to be removed, drive shaft nut in center of hub then 3 bolts hold the hub assembly to spindle from back side. if it has abs unplug it then some work will need to be done with a hammer and chisel to work the bearing out of spindle and axle shaft from bearing

SOURCE: replacing front wheel bearing

1. Loosen the wheel nuts and the center axle nut.
2. Raise the vehicle and safely support it.
3. Remove the wheel. Remove the ABS speed sensor if so equipped.
4. Unclamp the brake hose from the shock absorber, but do not disconnect the line.
5. Remove the brake caliper and hang it out of the way on a piece of stiff wire. Do not disconnect the brake line; do not allow the caliper to hang by the hose.
6. Remove the brake disc.
7. Place a dial indicator near the center of the axle hub, and check the backlash in the bearing shaft direction. Maximum is 0.0020 inch (0.05mm). If the backlash exceeds the maximum, replace the bearing.
   1. Usiung a dial; indicator, check the deviation at the surface of the axle hub outside the hub bolt. Maximum is 0.0028 inch (0.07mm). If the deviation exceeds the maximum, replace the axle hub.
   2. Install the disc and caliper. Tighten to 65 ft. lbs. (88 Nm).
8. Remove the cotter pin and install the wheel. Lower the vehicle to the ground.
9. Remove the lock nut cap. While depressing the brake pedal, remove the center axle nut.
10. Raise and support the vehicle again and remove the wheel, caliper and disc.
11. Loosen the 2 nuts on the lower side of the shock absorber. Do not remove the 2 nuts and bolts.
12. Remove the cotter pin and nut from the tie rod end.
13. Remove the tie rod end from the knuckle using a joint separator or equivalent.
14. Remove the bolt and 2 nuts holding the bottom of the ball joint to the control arm and separate the arm from the knuckle.
15. Remove the 2 nuts from the steering knuckle. Place a protective cover or shield over the CV boot on the driveshaft.
16. Using a plastic mallet, tap the driveshaft free of the hub assembly.
17. Remove the bolts and remove the axle hub assembly.
18. 1. Clamp the knuckle in a vise with protected jaws.
    2. Remove the dust deflector. Loosen the nut holding the ball joint to the knuckle. Use a ball joint separator tool or equivalent to loosen and remove the joint
    3. Use a slide hammer/extractor to remove the outer oil seal.
    4. Remove the snapring.
    5. Using a hub puller and pilot tools or equivalents, pull the axle hub from the knuckle.
    6. Remove the brake splash shield (3 bolts).
    7. Use a split plate bearing remover, puller pilot and a shop press, remove the inner bearing race from the hub.
    8. Remove the inner oil seal with the same tools used to remove the outer seal.
    
    To install:
    
    1. Place the inner race in the bearing. Support the knuckle and use an axle hub remover with a plastic mallet to drive out the bearing.
    2. Clean and inspect all parts but do not wash or clean the wheel bearing; it cannot be repacked. If the bearing is damaged or noisy, it must be replaced.
    3. Press a new bearing race into the steering knuckle using a bearing driver of the correct size.
    4. Place a new bearing inner race on the hub bearing.
    5. Insert the side lip of a new oil seal into the seal installer and drive the oil seal into the steering knuckle.
    6. Apply multi-purpose grease to the oil seal lip.
    7. Apply sealer to the brake splash shield and install the shield.
    8. Use a hub installer to press the hub into the steering knuckle.
    9. Install a new snapring into the hub.
    10. Using a seal installer of the correct size, install a new outer oil seal into the steering knuckle.
    11. Apply multi-purpose grease to the seal surfaces which will contact the driveshaft.
    12. Support the knuckle and drive in a new dust deflector.
    13. Install the ball joint into the knuckle and tighten the nut to 105 ft. lbs. (142). Install NEW cotter pin.
    14. Temporarily install the hub assembly to the lower control arm and fit the driveaxle into the hub.
    15. Install the knuckle to strut bolts, then attach the tie rod end to the knuckle.
    16. Tighten the strut bracket nuts to 203 ft. lbs. (275 Nm) and tighten the tie rod end nut to 36 ft. lbs. (49 Nm). Install the NEW cotter pin.
    17. Connect the ball joint to the lower control arm and tighten the nuts to 105 ft. lbs. (142 Nm).
    18. Install the brake disc.
    19. Attach the brake caliper to the knuckle and tighten the bolts to 65 ft. lbs. (88 Nm).
    20. Install the center nut and washer on the drive axle.
    21. Install the ABS speed sensor if so equipped. Install the wheel
    22. Lower the car to the ground.
    23. Tighten the wheel nuts to 76 ft. lbs. (103 Nm). Tighten the hub nut while depressing the brake pedal to 137 ft. lbs. (186 Nm) on 1988-91 models and 152 ft. lbs. (206 Nm) on 1992-97 models. Install the cap and cotter pin.
    24. Remove the protective cover from the CV boot. Check front wheel alignment

SOURCE: Procedure for replacing rear wheel bearings 2000 Forester

i'm assuming you don't have a hubshark,this is a tool that will alllow you to remove the bearing while the knuckle is attached to the car,you may be able to rent this tool at a auto prts store .if not you need to remove the entie knuckle,first remove the trailing arm bolt,then the lateral link bolt{long and stubborn bolt},disassemble the brake shoes and parking brake cable,abs sensor if equipped the knuckle to strut bolt{no marking necessary they are not eccentric} then you need a to use or borrow a press to remove hub and bearings good luck