Wheel bearings!

What is a wheel bearing?

Wheel bearing are one of the most crucial components of a car's suspension. They are usually located in the hub (the part that the brakes and wheels are attached to) or even the brake drum or rotor itself. Wheel bearings allow the wheel to rotate freely as the car travels down the road. Most cars have an inner and an outer bearing on each wheel.

Components

• A wheel bearing is a simple device made up of two main components, the bearing itself and the race. The bearing itself consists of a metal housing that is pressed over a row of ball bearings that circle the metal housing. These ball bearings in turn ride on the race, which is a very smooth metal surface. When a wheel is rolling, the action of the ball bearings rolling against the surface of the hub that allows the wheel to spin smoothly.

Wheel Bearing Problems

• Problems with wheel bearings arise from wear, which can be caused by a variety of factors. Bearings are protected from dirt and debris by oil seals. If these seals fail and dirt finds its way into the bearing, damage can occur to the bearing and the race. Another factor can be long-term wear, affecting the bearings' ability to function properly. If a bearing falls apart completely, it can render the car undriveable and dangerous. The brakes will not function correctly and the wheel will not stay in its proper orientation.

- How do I know if I need new wheel bearings? Most of the time we don't even know that they need service. We just drive and never think about them. Most car manufacturers recommend a wheel bearing clean, inspection and repack every 30,000 miles. This is usually done along with the front brake service. They need to be replaced when there is scoring and pitting or they become noisy.



How to replace a bearing.

1. First remove the bearing cap. This is a press fit and to remove it grab it with your Channelocks and work it back and forth until it pops off. Be careful not to crush it as you remove it.
2. Once the cap is off you will see a cotter pin, Remove the cotter pin and remove the retainer ring. If your vehicle has a castellated nut, you will not have a retaining ring.
3. Using your Channelocks or adjustable wrench, remove the nut from the spindle.
4. Now remove the outer wheel bearing and washer and lay it aside.
5. Slide the rotor or drum off the spindle. This may be difficult, but it will come off. Don't worry about hurting the grease seal; we're going to replace it anyway.
6. Now that the rotor or drum is off, use a suitable tool to remove the grease seal and take out the inner wheel bearing.
7. Using some of the rags wipe all the old grease from inside the hub.
8. Now we need to remove the bearing races from the hub. Take a punch with a flat narrow tip and place it on the back of the race. Most hubs have gaps in them to expose the back of the race to make removal easier. Tap the race out, alternating from side to side so it comes out evenly and doesn't get cocked in the hub. Once it's out, flip the rotor or drum over and do the same for the other race.

When both races are out, clean the inside of the hub with some rags. Also make sure the spindle is clean as well. You can even use some carburetor cleaner to do a really good job of cleaning. From this point on cleanliness is important. You do not want any dirt, sand or metal chips inside the hub.

                 

Now that everything is nice and clean, let's put the new races and bearings in.

Take one of the new races and coat the outside with some wheel bearing grease. This will help it slide into the hub. If you have a race driver, select the proper size and tap the new race into the hub. Make sure you drive it in evenly and do not cock it. If you don't have a race driver, use your hammer to tap the outside of the race to get it started making sure you tap evenly around the race. When it is flush with the hub, use your flat narrow punch and drive it in the rest of the way. Make sure it is fully seated. The sound of the tapping will change when it's seated and you can look from the other side to visually confirm this.

Do the same for the other race.

If you don't have a bearing packer, you will need to pack them by hand. Put a glob of wheel bearing grease in the palm of your hand. Slip the wheel bearing on your index finger like a ring with the wide end facing out. Then tap the bearing into the glob of grease until you see it coming out the other side. When you see it come out turn the whole bearing, don't just rotate it on your finger, and repeat the procedure until the whole bearing has grease coming out the other side. Repeat this for the other bearings.

1. Now that we have the races installed and bearings packed, we can put everything back together. Starting with the inner bearing put a bed of grease on the surface of the race and then push the inner wheel bearing into it. Take the new grease seal and tap it into place, don't bend or distort it. You can use a small block of wood to help.
2. Put a coating of grease inside the hub between the two races and on the spindle -- too much is better than too little. If any moisture should happen to get inside, the grease will keep the metal from rusting.
3. Slide the brake rotor or drum straight onto the spindle. It should slide on easily. If it doesn't, the bearing is cocked a little. Slide it off and make sure the bearing is sitting flat and try again.
4. Once it's on, grease the outer race and slide the outer wheel bearing on. Slide the washer on. The washer will probably have a tab that will align with the spindle, make sure that you line them up when you put it in.
5. Place the nut on the spindle and tighten it by hand until it won't go anymore. Spin the rotor or drum a few times back and forth and then tighten the nut more by hand. This insures that the bearings are seated. Do it a couple of times until you can't get it any tighter by hand.
6. Now tighten the nut ¼ turn, no more than 16 foot-pounds. If you have a castellated nut, line it up with the hole going through the spindle. Install a NEW cotter pin. If you have a retaining ring, place it on the nut and install the pin. Never reuse the old cotter pin and make sure you use it.
7. Put a small blob of grease on the inside of the dust cap and tap it into place, being careful not to crush it. Make sure it is fully seated.
   That's it, you're ready to roll nice and smooth!

                     

Symptoms

• Symptoms of a bad bearing are noisy rubbing as the car is driven and that usually gets louder as speeds increase. If the bearings are very worn, another symptom can be vague steering, vibrating suspension and darty behavior from the suspension as the wheel moves unevenly around the bearing.

Maintenance

• Bearings can be checked by jacking up the car and pushing on the wheel. If there is excessive movement of the wheel on the spindle, it's probably the bearing. Wheel-bearing maintenance is relatively simple but time-consuming, since the wheel, brakes and hub need to be removed. Once the bearing is visible, check the bearings for wear and the races for any scratches or wear. Clean everything thoroughly and repack the bearings with a generous amount of bearing grease. This should be done every 20,000 to 30,000 miles.

Replacement

• Replacing bearings can be time-consuming, but most accomplished home mechanics can do the job. It involves removing the wheel, brake and hub. Once the hub is off, the bearing races are removed and new ones pressed in. This is usually the most difficult part. Once the bearings are packed and installed, everything is reinstalled in the reverse of removal. Refer to a workshop manual for detailed instructions about your car's model. This should be done every 40,000 to 50,000 miles.

Warning

• A destroyed wheel bearing can result in a vehicle that is difficult to control. If you suspect that your bearings are bad, do not drive the vehicle until it is fixed or you know it is safe.

              

^ NEW BEARING !   ^ WORN BEARING

     (GOOD)                (BAD)