Friday, January 12, 2018

Wheel hub bearing replacement

The first time I went to engage the four wheel drive on Trouble this winter season I was greeted with a popping, clicking sound.  Upon examining the source, I determined that the wheel bearing had gone bad and the noise was being caused by the added stress of the four wheel drive system.  I also discovered that the half shaft was binding up too, but I am going to cover that in another post.

Replacing a wheel bearing is not that hard, usually.  But there are some tools that you will need to get the job done correctly, and they are (specific to my truck):

*1/2" breaker bar
*1/2" impact wrench (optional)
*32mm socket (deep well preferred)
*9/16" socket
*1/2" ratchet
*1/2" torque wrench
*anti-seize compound
*Loctite blue
*T47 torx bit (sometimes called a star bit)
*3/8" ratchet
*Large hammer
*Pliers
*Replacement cotter pin (if not included in the replacement hub assembly)

Step one is to remove the wheel, and then the brake rotor and caliper.  Dodge Durangos and Dakotas of this generation use a bolt that requires a T47 torx bit to remove and install.  All nuts and bolts should be set aside and organized so that they do not get lost.  When this is completed, this is what you will be looking at.


This is the front wheel bearing/hub assembly on the driver side of the truck.

The next step will be to remove the cotter pin, then the cap that is held on by the cotter pin. Discard the cotter pin. Set the cap and the wave washer directly behind it to the side.  Using an impact wrench and the 32mm socket, remove the axle nut, and the thick washer behind it, and set those aside.  Your wheel hub should now look like this:

Now, with the brake caliper sitting where it would be normally (to prevent damaging the brake line), turn the wheel and locate the three bolts with the heads facing the inside of the hub assembly.  They have 9/16" heads but are larger with respect to the threaded portion. Using a breaker bar to get them loose at first, remove the three bolts. You will probably have to turn the steering wheel to access all of the bolts.  The hub is now ready for removal.  Using the large hammer, hit the rounded portion of the hub to break it free.  This may take several attempts to accomplish. You may also want to lightly tap the end of the axleshaft, but if you choose to do this, reinstall the axle nut so that it is sitting flush with the threads as to avoid damaging them.  When this is done, you will be looking at this:

Using a wire brush, clean up the hole where the hub flange will fit into, then add a small amount of anti-seize to the inside of the hole.  Anti-seize is used to prevent metal parts from rusting and sticking together, making disassembly easier (in theory)

I purchased a First Equipment Quality (FEQ) brand replacement wheel hub assembly.  You will notice that the lug studs are already attached to the hub, and that the hub is one complete assembly.  It is possible to just replace the bearing portion of the assembly, but by the time you are finished paying someone to press out the old bearing and install the new one it's going to add up.  I prefer complete assemblies due to the time factor.  The most valuable commodity in the universe is time.

To install the hub, using your hands only (no hammers) place the hub into the hole and line up the bolt holes on the flange to the spindle. Apply Loctite to the bolt threads.  Start the three bolts into the flange but do not tighten them up just yet as you will need to again turn the wheel to get access to all of the bolt holes.  Once the bolts have been started, tighten the bolts that retain the hub to 90 foot pounds using the torque wrench.  Do not guess, do not assume they are tight enough. Use a torque wrench.

Install the large washer and axle nut and tighten to 175 foot pounds.  Loctite is not required as a cotter pin is used to help keep the nut from backing off.  Again, do not guess the torque.  If there is not enough torque on the nut, the axle will shimmy around and it may fail.  Too much torque and the bearing will burn itself out prematurely due to excess friction, which causes heat.

Install the wave washer, castle cap and a new cotter pin.  The picture below shows the proper way to bend a cotter pin to prevent it from falling out.
The final steps involve reinstalling the brake rotor, caliper and wheel.  Road test the vehicle and listen for any odd sounds coming from the driveline.  This is the part where I felt the axle bind up when testing the four wheel drive.  This will end up being the next post, wherein I replace the axle, hopefully before the next major snow.