Jeep WK Unit Bearing Wheel Speed Sensor

At 185’000 kms Jeep began drivetrain began acting funny and traction control ABS began triggering and operating incorrectly making the Jeep virtually not drivable. The change went from no problem, to immediate problem from one day to the next without any sort of irregular driving or off-roading. Checked with code reader and resulted in Code: C101F Right Front Wheel Speed Comparative Performance. (Wheel Speed Sensor) (This part is referred to as a wheel bearing, hub bearing or unit bearing)

Jeep WK C101F
Wheel Speed Sensor Code Jeep WK C101F

The price for a replacement wheel speed sensor cable was about $50 CAD at local parts store. Unit Bearings were priced starting around $85 CAD including wheel speed sensor. Since the Jeep and current bearings have about 185’000 kms and this Jeep is built for Overlanding and long term use, the decision was made to change the entire Unit Bearing. Since we were doing one side the decision was made to change both. Although a big believer in not fixing “what aint broke”, we are looking to put on 15-40’000 kms on our next trip depending on various life circumstances. Needing to change a Unit bearing on the road is not high on the bucket list of “want to do” road trip tasks, so both were swapped out. Since the WK was now virtually inoperable, I think it may have driven normally with the traction control turned off, but I can not remember for certain now, a new Unit Bearing was sourced locally for ~$200 CAD. Also needed was a 36 mm socket. N.B. Although a normal depth socket worked fine for stock Mopar CV axle nut, the driver’s side axle had been replaced with a JBA 4xguard axle shaft at around 105’000 kms, The amount of threaded axle rod protruding on that side was more than enough to make it very difficult to get the socket to grip on the 36 mm locking nut that hold the axle into the unit bearing. We actually used a mini-grinder to take a few mm off of the threaded end of the shaft and then clean it up so it would rethread with a new nut. Also note, the Mevotech TXF513234 Titan-XF bearing comes with nice coated bolts and a locking nut, but the 4xGuard axle has a finer thread than the stock and Mevotech threads, so we were unable to use the coated Mevotech nut.

Mevotech TXF513234Titan-XF Wheel Bearing

So to begin jacking the Jeep, jack stands under the chassis and frame, and then a hydraulic jack under the lower control arm to be able to raise and lower the wheel hub and steering knuckle as needed. The 36 mm nut is more easily removed with the tire on and weight of vehicle on the tire. The AEV Savegre wheels just allowed the 36 mm socket to fit through the center hole to remove the axle nut. After that the calliper bracket was removed by removing the two bolts holding it to the steering knuckle and then hung out of the way with a chord or wire so there is no strain on the brake fluid hose. In the photo below you can see the wire already hanging secured above ready to accept the heavy calliper and bracket.

Calliper Bracket Removal 2007 Jeep WK Unit Bearing
Calliper Bracket Removal
Jeep WK on jack stand for wheel bearing change

Note there is a second safety Jack stand on the Unibody frame rail to the left, and the tire is also under there in case the vehicle shifts and were to fall. Safety First. A wire coat hanger is used to hold the brake calliper up by snaking one end through the calliper mounting bolt hole, and wrapping the other around the UCA, or the a spring coil.

Removal of three bolts holding bearing into steering knuckle

As you can see there is a fair amount of road crud which needed to be cleaned up, but this can be done easily once the bearing has been removed. A 15 mm socket with extension does the job. Be aware, that the steering wheel needed to be turned left to right to center a few times through out this process. If you are doing this repair on a roadside make sure that your vehicle is safely blocked as turning the wheel, especially with large front tires can cause the vehicle to shift side to side on the supporting, jacks, blocks etc. Once the three bolts holding the unit bearing are removed, and the axle nut off of the end, the Unit bearing will pop right off. (With a little help form the tap hammer)

2007 Jeep Grand Cherokee Wheel Bearing Removal
2007 Jeep Grand Cherokee Wheel Bearing Removal with tap hammer after three bolts removed.

It is a good idea to disconnect the wheel speed sensor from the connector on the inside of the wheel well, and disconnect the wire form the grommet clips that hold it in place. You should be able to reuse all of these if you open them carefully with a small screwdriver or whatever works best for you. You do not want your wheel speed sensor wire floating around loose with the chance to be snagged and ripped free by your rotating tire.

2007 Jeep WK STeering knuckle with bearing removed
Steering knuckle ready for cleanup and new bearing

While here this is an easy time to check other components and perform other maintenance. I knew I had a leaking CV boot, so I had purchased a Moog Outer CV boot with grease and clips. Since the axle nut needs to be taken off it was the ideal time to perform this task. That is another story, but suffice it to say the grease in the CV bearing was extremely dry and it definitely benefitted from repacking and a new boot. I also checked my lower ball joints which as suspended had a “little play”. I had replaced these with Moog Problem Solvers about 80’000 kms ago.

Moog Problem Solvers after 80’000 kms.

These have since been replaced by Mevotech TTX on both sides. The original Moog were under warranty, but with shipping, labor etc the warranty does not mean much.

Mevotech TTX LBJ for 2007 Jeep WK

Moving right along, with the bearing out the knuckle and various parts were cleaned up with brake cleaner, wire brush, wire wheel scraper etc. Since no Lower Ball joint had been procured at this point, the wheel would have to come off again at a later date. The bolts need to be pushed through the back of the knuckle first and they hold the dust plate, brake backing plate in place until you align the bearing assembly and get the bolts to start to thread.

Unit bearing mounting bolts through steering knuckle Jeep WK 2007 Mevotech Titan-XF
Unit bearing mounting bolts through steering knuckle Jeep WK 2007

At this stage it is important to pay attention to things like which way the backing plate should face, and how it is oriented, as well as how you will orient the wire for the wheel speed sensor on the unit bearing.

Unit bearing mounting bolts through steering knuckle Jeep WK 2007
Unit bearing mounting bolts

(note the blue anti corrosion coating on the Mevotech Titan-XF bolts and axle nut) make sure your sensor wire is oriented properly. Below is wrong. In this Nine O’clock position the sensor wire sits in the middle of the brake calliper and the wire does not go through the hole in the backing plate located at Two O’clock.

When mounting the unit bearing this is incorrect orientation for the sensor wire.

Here is a photo of the wire and backing plate as it should be with properly oriented unit bearing mounted and tightened up. This photo is taken from the front of the Jeep just inside the wheel looking to the back.

2007 Jeep WK Wheel bearing sensor wire
2007 Jeep WK Wheel bearing sensor wire

After installing and torquing the unit bearing to 85 ft-lbs and axle nut 229 ft-lbs (2006 and later) properly and putting the wheel on, the Jeep was taken for a test drive to assure the codes would clear and the problem was solved. I thought I would try to pull the sensor out of the old bearing in case somebody else needed it since the bearing itself did not actually have nay issues. This was done also to see whether it would have been easy, or even possible to just swap the sensor instead of buying the whole bearing.

Removing sensor retaining bolt was easy
2007 Jeeep WK wheel bearing sensor
2007 Jeep WK wheel bearing sensor

As you can see the plastic sensor broke off in the hole in the hub. After this I tried drilling it out and seeing if I could have made a new sensor wire work. With the amount of corruption in the sensor hole I am not sure it would have worked, and it would have been more work to maybe find the new sensor would not work, plus losing $50 CAD for the sensor. All in all I getting these bearings replaced was a preventative maintenance task that was on the list, and now that it was done, should not need to be done for the life of the truck. People have been asking me about how the Mevotech LBJs and bearings are holding up, and honestly the true test is time and miles. For now no complaints and the build quality seems exceptional. If they fail, or I have problems with sensors etc I will post it here as quickly as possible. For now all is good. Feel free to p.m. me, or write in comments if you have any questions.

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