Jump to content
Disconnected Offroad
Sign in to follow this  
Nascar

Jeep JK Unit Bearing

Recommended Posts

Have a shimmy or shake at speed? You can tell your unit bearings (AKA Wheel Bearings/Hubs) are bad by jacking up the front end, placing a pry bar under the tire and prying up and releasing multiple times. Have a partner watch for movement of the wheel inboard and outboard. Make sure you're not misdiagnosing it for the ball joints. They will move at where the knuckle mates with the outer C's. 

 

If you have movement in the unit bearing they are toast.  Other ways to diagnose bad wheel bearings is a hum at speed. It will be a rotational noise that increases as speed increases. You may also experience ABS related issues. 

 

The Unit Bearing connects the tire/wheel/rotor to the knuckle. It also has a Hall effect sensor used for ABS. 

 

If you have drivability issues associated with the unit bearing, DON'T WAIT and DON'T FRET!!! It is an easy repair, and I like to do them in pairs. If one side fails, the other isn't far away. It gives you the peace of mind to replace as a set.

 

Timken Unit bearings are pretty much the best I've seen and worked with. They come with a new ABS sensor which is a plus.

 

Part Number: HA590242

 

Rock Auto usually stocks them at both warehouses.

 

Replacement is relatively simple, and PB Blaster is your friend.

1. Jack up vehicle and put on jack stands.

2. Remove both front tires and the 36mm nut holding the axle shaft to the hub assembly, you may use the brakes to prevent the axle from spinning as you loosen the nut.

3. Remove both front brake assemblies.

4. Remove ABS sensor using 5mm hex, also disconnect connector behind the shock towers.

   ---Reference '&do=embed' frameborder='0' data-embedContent>>

5. Remove 3 13mm 12point bolts holding the unit bearing to the knuckle.

6. Using a slide hammer, remove the hub from the knuckle. remember that you don't have to pull the whole axle shaft out.

7. Clean up any rust from the 12 pt bolts and the recess in the knuckle where the unit bearing sits. I like to rub some anti-seize or grease on the mating surface, as well as the axle shaft splines. This allows for easier removal in the future. This is also a good time to throw out the dust shields. They like to collect rocks and such and cause an awesome sound. (Do this at your own discretion as removal of the dust shield opens up your brake system to foreign objects.)

8. Install the new unit bearing, aligning the axle shaft splines, and orientating the abs sensor port to the front of the jeep. (Should be pointing up at the bumper.)

9. Tighten the 13mm 12 point bolts. You can tap the unit bearing lightly into the knuckle and then use the bolts to seat it fully. If you start to struggle with the bolts, don't force it, make sure everything is aligned properly and try again.

10. If removed, reinstall the new ABS sensor into the port and fish the wiring back through the knuckle into the holding clamps and up to the connector behind the shock tower. Make sure the sensor is clean and free of debris.

11. Reinstall rotor and brake assemblies. Making sure to properly tighten all hardware.

12. Using the brakes again, tighten the 36mm axle nut.

13. Reinstall wheel/tire assembly and tighten lug nuts.

 

Enjoy your jeep again. If the ABS light was on, it will go out after a sustained 5mph.

  • Like 4

Share this post


Link to post
Share on other sites

Nice write up. Very easy upgrade, even my dumbass pulled it off! Careful with the 3 bolts holding the bearing on, a few of mine busted. They are about $7 from the dealer. I have a few extra ones in case anyone needs any.

Share this post


Link to post
Share on other sites

I couldn't find the Timkins locally.  My choice was Duracrap or Moog.  I went with the Moog PN# 513272 for $145.  Couldn't wait for shipping because Dylan's car is going to be out of commission until I at least get the side window replaced. 

 

I don't know how you snapped the hub bolts.  I broke a Craftsman ratchet and a Gear Wrench trying to get the last bolt out. 

Share this post


Link to post
Share on other sites

Oh, lest I forget:

 

Put the vehicle in 4WD and you won't need someone to stand on the brakes when you try to loosen or tighten the axle nut.

Don't forget anti-seize on the shaft splines, outer hub mating surface and all bolts. 

 

Torque specs:

 

* Axle Nut: 100 ft/lbs

* Hub Bolts: 75 ft/lbs

* Brake Caliper Adapter: 120 ft/lbs

 

Have fun trying to get a torque wrench in there for the hub bolts.

Share this post


Link to post
Share on other sites

Flex sockets get you close enough on torque if you don't have 12pt crows foots

Share this post


Link to post
Share on other sites

Flex sockets get you close enough on torque if you don't have 12pt crows foots

 

Probably, but I've never even SEEN 12pt crows foots.  The only 12pt 13mm socket I had was 1/4" drive.  Sheared the cheap Chinese 3/8 to 1/4" adapter off like it was butter.  I need to got to Schaeffer Supply or Fastenal to get a 13mm 3/8" socket.

Share this post


Link to post
Share on other sites
Sign in to follow this  

×
×
  • Create New...