Shown: 2006 M35 Sport 2WD, right wheel.
Partial list of tools/supplies required:
[click on any image for larger]
- Socket, 10mm x 3/8" drive (for speed sensor)
- Socket, 17mm x 1/2" drive (for hub mounting bolts)
- Socket, 21mm x 1/2" drive (for lug nuts; can substitute lug wrench)
- Socket, 22mm x 1/2 drive (for caliper bracket bolts)
- Anti-seize for reassembly
- Sandpaper or equivalent
- Mechanic's wire or a box (to support caliper when dismounted from knuckle)
- Penetrant (for disk/hub interface)
- Wood/stick, 1-1/8" x 4" approx.
- Scrap wood chunk for disk removal
A helper is recommended, as the steering wheel must be turned from one lock to the other several times, and it's very nice to have someone with clean hands doing this
Warn your helper to never touch the brake pedal!
Read on for an explanation . . .
2WD exploded view of steering knuckle & hub. From the online FSM
, page 5.
If your vehicle is AWD, you will have to remove one more nut (in the centre of the hub, the end of the axle) and one more step (press axle back out of hub). See the FSM.
Loosen lug nuts
Begin by setting the park brake, loosening lug nuts (21mm)
Raise & block the vehicle, remove wheel
Check for proper lift and block location (see FSM General Information, pg 43
but I used the engine subframe-to-body mount point instead), then remove the wheel.
Remove brake caliper
Have helper turn the wheels so the front of the wheel you're working with is "outward"; this provides access to the brake caliper bracket bolts. Remove two bolts (22mm). An air impact wrench is shown, but a breaker bar works just as well.
Remove the caliper
The FSM suggests unbolting the brake hose bracket. I didn't see that that would be particularly helpful. The caliper should not be allowed to "hang" on the brake hose -- that can damage the hose. Instead, either set the caliper on a suitable prop (I used a square plastic bucket), or hang the caliper from the knuckle using wire.
Once the caliper is removed from the knuckle, you will be facing the bare disk on the hub.
Safeguard the caliper
Before you do anything else, safeguard your caliper by placing a block of wood between the brake pads. Why? If your helper presses the brake pedal with the caliper removed from the disk, one of the caliper pistons may exit the caliper housing, causing much grief, doubling the cost of the job and quadrupling the job completion time. You will want wood about 1-1/8" thick.
Grab the disk and pull. If you're lucky, the disk will slide right off the studs.
If you're like most of us, it won't budge. Use your favourite penetrating oil here, but don't get carried away; use only enough to saturate the hub. Any oil that migrates to the disk's outer edge will have to be removed before reassembly.
Then, use a scrap piece of wood and a hammer to persuade the disk to break free of the hub. Place the wood on the shiny bit of the disk you see, where the outside pad contacts the disk. Whack the wood with a hammer. Yes, toward the engine. The disk will rock, the edge of the disk you are not
whacking will tilt outward. Don't try to whack the backside of the disk, you'll only bend the shield and such.
View with the disk removed.
Remove wheel speed sensor
While you move your caliper prop (if using a prop), have your helper turn the wheels the opposite direction fully, giving access to the wheel speed sensor.
Remove the 10mm-head bolt, and attempt to withdraw the sensor from the knuckle.
The FSM warns: Do not pull on sensor wire, or sensor will be damaged.
Penetrating oil might be necessary here too; ours did not.
Remove wheel hub bolts
With the sensor out of the way, the two rearmost hub retaining bolts can be removed (17mm socket).
Have your helper once again turn the wheels the opposite direction fully, to obtain access to the forward two hub retaining bolts.
Once all four hub retaining bolts have been removed, use the hammer on the hub flange's backside to persuade the hub to dismount from the knuckle. Again, penetrating oil may be helpful here. There's no need to be gentle, the hub is not going to be used again.
View with hub removed. the shield falls off when the hub does.
Prepare hub bore
Before mounting the new hub, clean up the bore of corrosion and crud.
As all the best repair manuals say (including the FSM for this job), "to reassemble, reverse above procedure."
Use anti-seize sparingly
in the hub-to-knuckle bore;
When positioning the new hub to the knuckle's bore, take note of the wheel speed sensor access slots at the back of the hub. It appears than one can mount the hub to the knuckle right or wrong -- the FSM is silent on this issue, and I didn't check myself. If mounted wrong, the wheel speed sensor may not insert fully into the hub. Best to look for sensor hole/slot alignment before bolting the hub up.
Use anti-seize sparingly
where the disk centers on the hub;
I also use anti-seize on all the threaded fasteners upon reassembly.
Torque the hub-to-knuckle bolts to 65 ft-lbs.
Torque the caliper bracket-to-knuckle bolts to 98 ft-lbs.
Wheel lug nuts: 80 ft-lbs.
Ours went smoothly; I changed out our hub in approximately 45 minutes, including snapping the pics and cleanup. Writing this article took about three times as long
If you find errors, bring them to my attention and I'll attempt to edit this article.