I need a diagram of the front wheel bearing assembly. I need to know how to remove the right front wheel bearing and remove - reinstall the center "geared insert" in the bearing without damaging it, plus how to remove the bearing from the hub without damaging the hub

For front wheel assembly diagram and replacement,click the link below and go through procedure:----Front wheel hub assembly Diagram and replacing procedure? http://howtobyme.blogspot.in/2012/02/front-wheel-hub-assembly-diagram-and.html
----------Front wheel assembly diagram to replace wheel bearing? http://howtobyme.blogspot.in/2012/02/front-wheel-assembly-diagram-to-replace.html
-------------How to replace Front wheel bearing? http://howtobyme.blogspot.in/2012/02/how-to-replace-front-wheel-bearing.html
-----------Check all 3 links one by one.This will help.Thanks.

Removal & Installation Front To Remove:
The front wheel bearings are not serviced separately. If the front wheel bearings are defective, the hub and bearing assembly must be replaced.

1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
2. Lubricate the threads on the halfshaft with clean engine oil.
3. Remove or disconnect the following:
   • Front wheels
   • Halfshaft hub nut
   • Caliper from the steering knuckle WARNING
     DO NOT allow the brake hose to support the weight of the caliper.
     
   • Brake rotor
   • Anti-lock Brake System (ABS) sensor from the backing plate
   • Hub and bearing assembly from the backing plate
   • Hub and bearing assembly from the halfshaft
   • Hub and bearing assembly

To Install:
Exploded view of the front hub mounting and related components

1. Install or connect the following:
   • Hub and bearing assembly onto the halfshaft
   • Hub and bearing assembly to the backing plate. Torque the 3 bolts alternately and evenly to 70 ft. lbs. (95 Nm).
   • ABS sensor
   • Brake rotor
   • Caliper on the steering knuckle.
   • Halfshaft nut. Torque it to 118 ft. lbs. (160 Nm).
   • Front wheel. Torque the nuts to 100 ft. lbs. (140 Nm).

Remove center hub cap. Remove large nut behind hub cap.Lift wheel assembly off ground. Remove wheel. Remove brake calipher assembly by taking out larger bolts from back of calipher. Remove brake rotor. Pull axle toward middle of vehicle, you may have to tap axle end with small hammer being careful not to damage threads on end of axle. Remove three bolts from back, bearing housing should come out to the front.

While you did not mention the year, front or rear hub I have done most.
The hub bearing assembly is a sealed bearing that mounts with three bolts coming in from the axle side. An air impact gun will be required to remove the drive axle spindle nut that passes thru the center prior to disassembly. Remove the axle nut, three hub fasteners and ABS wire harness to the wheel speed sensor. Reinstall in reverse order

8–Stud Rotor

1. Raise and support the vehicle.
   
2. Remove the wheel.
   
3. Remove the hub extension.
   
4. Remove the brake caliper assembly.
   
5. Remove the axle nut cotter pin. Remove the axle nut.
   
6. Disconnect the ABS wheel speed sensor wire from under the hood. Remove the sensor wire from the frame and steering knuckle, if equipped.
   
7. Back off the hub/bearing mounting bolts 1/4 inch each. Then tap the bolts with a hammer to loosen the hub/bearing mounting bolts.
   
8. Remove the bolts and remove the hub/bearing assembly.
   

NOTE: After the wheel bearings have been removed or replaced or the front axle has been reassembled be sure to adjust wheel bearing preload. Refer to the Adjustment service procedure below. On the 1989–92 240SX there is just one wheel bearing, pressed into the hub and no adjusting cap. Refer to the exploded views of the Front Axle Hub Assembly. Review the complete service procedure.

1. Raise and support the vehicle safely.
2. Remove the front wheels and the brake caliper assemblies. NOTE: Brake hoses do not need to be disconnected from the brake caliper assemblies. Make sure the brake hoses are secure and do not let caliper assemblies hang unsupported from the vehicle.
   
3. Work off center hub cap by using thin tool. If necessary tap around it with a soft hammer while removing.
4. Pry off cotter pin and take out adjusting cap and wheel bearing lock nut.
5. Remove wheel hub with disc brake rotor from spindle with bearings installed. Remove the outer bearing from the hub.
6. Remove inner bearing and grease seal from hub using long brass drift pin or equivalent.
7. If it is necessary to replace the bearing outer races, drive them out of the hub with a brass drift pin and mallet.
8. Install the outer bearing race with a tool (KV401021S0 special tool number) until it seats in the hub flush. NOTE: Place a large glob of grease into the palm of one hand and push the bearing through it with a sliding motion. The grease must be forced through the side of the bearing and in between each roller. Continue until the grease begins to ooze out the other side through the gaps between the rollers. The bearing must be completely packed with grease.
   
9. Pack each wheel bearing with high temperature wheel bearing grease. Pack hub and hub cap with the recommended wheel bearing grease up to shaded portions. Refer to the illustration.
10. Install the inner bearing and grease seal in the proper position in the hub.
11. Install the wheel hub with disc brake rotor to the spindle.
12. Install the outer wheel bearing, lock washer, wheel bearing lock nut, adjusting cap, cotter pin (always use a new cotter pin and O-ring for installation after adjustment), spread cotter pin then install the O-ring and dust cap.
13. Install the brake caliper assemblies and bleed brakes if necessary. Install the front wheels.

sounds like a bad wheel bearing..if drum brakes,remove drum and center cap from wheel bearing..remove center nut and pull bearing from spindle..replace hub/bearing assembly and center nut..if disc brakes,remove caliper/rotor,and hub/bearing assembly

What year miata?

If they are sealed bearings, you will need a press to get them out. If they are bolt in, just remove the brake pads/rotors, then the axle nut, then the bolts holding the wheel bearing in. Install in reverse order.