Drag Race 101: How to Pack Wheel Bearings and Change Bearing Races
Wheel bearings allow your car’s wheels to spin freely. Every now and then a procedure known as “packing the bearings” needs to be done. This forces the old grease out and pushes new grease in. There are a few reasons this should be done on an annual basis, but the most important is that the grease breaks down over time. If the grease is allowed to break down sufficiently, the bearing will overheat and can actually weld itself to the race and the hub. Alternately, the bearings loosen over time, allowing the wheel to wobble. If left untreated, this can be bad. Very bad.
Packing the bearings isn’t a difficult project. It can usually be done in less than 90 minutes for both sides. The tires have to come off. The brakes have to come most of the way off. Then you can remove the bearings, repack them, replace them, install a new seal, and put everything back together. I’m going to presume that I don’t need to tell you how to remove the wheels.
Test Old Bearings to See If They Need Packing
It goes without saying that new bearings must be packed with grease before use. Not all old bearings will require repacking though. You can see if yours need repacking by grasping the wheel (in the air) and pushing and pulling at the top and bottom. If only the sidewall flexes, you’re ok. If you feel a bit of a knocking or see the wheel moving, repack the bearings.
What You’ll Need
You’ll need the following for this project:
- High speed bearing grease
- New grease seal
- Large slipjoint/Channellock pliers
- Wire cutters
- Seal installation tool or block of wood
- Half inch diameter punch, preferably brass
- Two blocks of wood
Step 1: Remove the Hub and Outer Bearing
With the wheels off, use a pair of slipjoint pliers to rock the dust cover off the hub. Using smaller pliers or wire cutters straighten the cotter pin and pull it out. Since they’re cheap, I usually keep a box of these in my toolbox. Pull the castellated (grooved at the top) nut cover off and use the large pliers to remove the spindle nut.
Bump the bottom of the brake rotor or drum with the butt of your hand to pop the grooved washer and lower bearing out. If you’re planning on reusing the bearing, wiggle it for looseness and check the bearing rollers for scorching (blueness) or pitting. If you find these conditions, replace the bearings and races. Next, wiggle the bearing around and check for looseness between the rollers and cages. If excessive (you’ll recognize it), replace them.
Step 2: Remove the Grease Seal and Outer Bearing
Thread the spindle nut back onto the spindle a few threads. Grasp the inside (towards the center of the car) of the drum or rotor and pull, using moderate force. You should end up with the drum or rotor in your chest and the inner (larger) bearing and seal hanging on the spindle. Remove the spindle nut, bearing, and seal. Set everything on a shop towel. Wipe down the inner bearing and race and inspect for bluing or nicks. If present, replace them.
Step 3-1: Packing Bearings the Clean Way
A number of companies make a product that makes packing bearings a pretty clean project. They are all variations on two cones that fit together. The bearings are stacked outer on top of inner and the top portion of the tool is screwed down onto the lower portion.
With some of these tools, this is all that needs to be done to pack the bearings. With others, you need to pump grease into the tools. Either way, force the old grease out and new grease in until you see new grease pumping out between the rollers and cage and the two cage halves.
Step 3-2: Packing Bearings the Old Way
Although the old way is messier, I prefer it because it allows me to ensure that I get the bearings packed properly. Gloves help keep it from being overly messy.
- Fill your palm with clean grease
- Hold the bearing as indicated in the picture above and push it into the pile of grease, firmly
- Make sure you push all the way to your palm as this is what actually forces the grease into the cage
- Repeat this until fresh grease squeezes out
- Rotate the bearing and repeat the process until grease is pushing out all around it (Images below)
- Repeat on the other bearing
Step 4: Remove the Old Races
If your old bearings and races were in good shape, skip the next two steps and go on to installing the rear bearing and seal. Turn the rotor/drum up so the backside is in the air and set it on the two blocks of wood so the opening to the hub is elevated. Clean the inside of the hub out some to remove enough grease so you can see what you’re doing. Inside the hub, you will see two grooves behind the outer race.
Place the (brass) punch in this groove against the backside of the race. Strike the punch firmly with the hammer until the race moves. Move the punch to the opposite side and repeat. This should release the race, but if not, go back to the first side and repeat. Flip the hub assembly over and repeat for the inner race (or outer, your choice).
Step 5: Install the New Races
Choose a side, inner or outer. Put a light film of grease on the outside of the race and insert it into position. Using the hammer and tap around the perimeter of the race until it is firmly in its groove. Lay a block of wood or the punch across the race and strike it firmly, driving the race into position evenly. With the race flush with the edge of the hub, use the punch, alternating side to side, to fully seat the race. Repeat on the other side.
Step 6: Install the Inner Bearing and Grease Seal
Wipe the inner bearing race clean with a rag and then give it a light coating of fresh grease. Drop the inner (larger) bearing into place, small end first. Set the seal over the backside of the hub and, moving around the edge, lightly tap it into place. You can also use the block of wood, a seal installation tool, or the punch laid flat across the seal to get it drive in evenly. Drive it in until it sits flush with the hub.
Step 7: Install the Outer Bearing and Button It Up
Slide the hub assembly over the spindle until the hub is fully seated on the spindle. Slide the outer bearing into place, small end first. Next, slide the keyed washer over the spindle, lining up the groove in the spindle with the tongue in the washer. Thread the spindle nut onto the spindle. Tighten it sufficiently that the rotor/drum doesn’t wiggle when you push/pull at top and bottom, but not so much that the rotation of the hub is impeded. Slide the castellated/grooved spindle nut cover over the nut, lining up the grooves with the hole in the spindle. Slide the cotter pin into the hole and bend it over or around the spindle to hold it in place.
Now you just need to repeat the above steps on the other side, hang the tires, lower it, and go driving.