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Front Wheel Bearing Replacement
 
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Pelican Technical Article:

Front Wheel Bearing Replacement

Time:

4 hours4 hrs

Tab:

$15 to $30

Talent:

****

Tools:

Socket set, hex socket set, drift or large socket set, large vice grips.

Applicable Models:

Porsche 911 (1965-89)
Porsche 912 (1965-69)
Porsche 930 Turbo (1976-89)

Parts Required:

Bearings, grease seals, high temp grease

Hot Tip:

Be careful when driving the old race out

Performance Gain:

Restore a tight feeling to the front end of your car.

Complementary Modification:

Replace brake pads and discs

If you are starting to hear a low rumbling sound from your front end or your 911 has over a 100,0000 miles on it you should inspect your front wheel bearings for replacement. The bearings support the full weight of the car both while stationary and under load. As the mileage increases on the car, heat and lack of lubrication can cause the bearings to wear and possibly fail. Replacing the bearings isn't a difficult procedure, but it does involve a commitment to the job as you will be destroying some old parts in removal and will not be able to use the car until the new ones are installed. Make sure you have everything you need before you start.

Before you begin the job place the new races in the freezer, preferably over night if you can. Freezing the races will decrease the other diameter and make installation into the hub easier.

You will need to first remove the brake caliper and rotor or discs. Please see our articles on removing your calipers and disks.

Once the calipers and pads are removed, you'll have access to the wheel bearing hub. If you are going to be installing new rotors while performing this job leave the old ones on while working. The old rotors will provide a wider base or more stable platform while working on the hubs.

Remove the dust cap from the front of the wheel hub.
Figure 1

Remove the dust cap from the front of the wheel hub. You will need a very large set of vice grips or channel locks to grasp and gently rock the dust cap (yellow arrow) off.

With the dust cap removed you can see the axle nut that sits at the center (red arrow).
Figure 2

With the dust cap removed you can see the axle nut that sits at the center (red arrow). It's a good idea to wipe off any excess grease on the nut. Use a 6mm Allen key (yellow arrow) to loosen the clamp on the axle nut. This clamp holds the axle nut in place on the spindle. Once you loosen the clamp, you should be able to easily unthread the nut from the spindle.

With the axle nut removed, you will be able to pull the hub off.
Figure 3

With the axle nut removed, you will be able to pull the hub off. As you do, the outer wheel bearing will pop out. The tapered bearing sits inside a race that is pressed into the hub. Check the races and bearings for any scratches, grooves, discoloration or scorching. These are signs that the bearing is worn and requires replacement (red arrow). The rollers should also be tight not loose.

Clean all the grease off the spindle (red arrow) and check it for wear as well.
Figure 4

Clean all the grease off the spindle (red arrow) and check it for wear as well. If the spindle shows any grooves or pitting, you'll want to replace it.

With the wheel hub removed from the car, turn it over to the back side.
Figure 5

With the wheel hub removed from the car, turn it over to the back side. You'll see an oil seal pressed inside (yellow arrow). You'll first need to remove this seal to remove the inner bearing and race. Use a seal puller to remove the old oil seal from the wheel hub. If you don't have a seal puller you can use a large flat head screwdriver and something to give you leverage (red arrow). It will take a fair amount of force to pry the old seal from the hub so don't be afraid if the old seal deforms or bends as you pull it out. These are designed as one time use items and you will more than likely destroy it as comes out.

Now you will have to remove the races that remain inside the wheel hub.
Figure 6

Now you will have to remove the races that remain inside the wheel hub. To remove the outer bearing race, you will need to use a drift; I found a part of a Mercedes bearing removal kit that fit perfectly (yellow arrow).

You want to apply an even force to all sides of the race when removing.
Figure 7

You want to apply an even force to all sides of the race when removing. You can use a hammer to drive it out but I prefer to use a press. If you have a press it is best to use it as this will keep even pressure side to side when removing or install the races.

For the larger race on the opposite side, you'll have to use a smaller socket or large punch and hit the edge of the race at an angle.
Figure 8

For the larger race on the opposite side, you'll have to use a smaller socket or large punch and hit the edge of the race at an angle. It helps to hit the race around the diameter of the edge to drive it out evenly (red arrow). You will not be a able to get a large enough socket inside the hub to apply even pressure during removal so take your time and constantly rotate the hub to remove the race as evenly as possible. Patience is a virtue here as you need to make sure you do not to damage or scratch the inside bore of the wheel hub.

Take the new inner bearing race and place it in the bore on the rear of the hub (red arrow).
Figure 9

Take the new inner bearing race and place it in the bore on the rear of the hub (red arrow). Porsche makes an expensive tool to seat the race but you should be able to find a socket large enough to use to press the race in. I found an old ball socket that fit perfectly. You'll want to position the tapered section to accept the bearing. Now press the bearing race into the hub until it seats against the bottom flange of the hub. If you are having to do this with a hammer take your time and make sure that the race goes in straight. It's very easy to cock the race in the bore. Install the outer race in the same manner.

Before installing the bearings into the wheel hub, it's necessary to pack them with grease.
Figure 10

Before installing the bearings into the wheel hub, it's necessary to pack them with grease. The idea here is to fill all the open spaces of the needle bearings. There are a couple different ways of doing this. You can buy a wheel bearing packer, which uses pressure to push the grease in from the open ends or if you are doing it by hand push grease in through the openings on the ends (red arrow) until grease comes out the other end, then rotate the bearing back and forth.

I highly recommend getting a bearing packer (yellow arrow).
Figure 11

I highly recommend getting a bearing packer (yellow arrow). Pelican Parts sells a few different ones; they are cheap, very effective at packing the bearings with grease and make what might be one of the messiest jobs in all of motorsports clean and easy.

Be sure to also put a coat of grease on the face of the bearing race (yellow arrow).
Figure 12

Be sure to also put a coat of grease on the face of the bearing race (yellow arrow). Once the bearing is packed, drop it in place on the hub. It's not a bad idea to hold the inner part of the needle bearing and then turn the hub to distribute more grease thru the bearing.

Clean any grease that may be on the inner races of the bearings (red arrow) as you want the bearings to spin in the races not the races to spin on the spindles.
Figure 13

Clean any grease that may be on the inner races of the bearings (red arrow) as you want the bearings to spin in the races not the races to spin on the spindles.

Now fit the wheel hub back over the spindle and push it back until the seal pops over the flange on the back of the spindle.
Figure 15

Now fit the wheel hub back over the spindle and push it back until the seal pops over the flange on the back of the spindle. Install the freshly packed outer bearing keeping in mind that the tapered section of the bearing fits into the race facing inward (red arrow).

You'll now need to adjust the wheel bearing.
Figure 16

You'll now need to adjust the wheel bearing. While rotating the disc and bearing hub tighten the locking nut in small increments until the thrust washer (yellow arrow) can barely be moved back and forth with the light push of the tip of a screwdriver. Then tighten the 6mm bolt on the end of the nut to spec.

The last step is to put a little of the high temp grease on the inside of the dust cap (yellow arrow) and place it back onto the hub.
Figure 17

The last step is to put a little of the high temp grease on the inside of the dust cap (yellow arrow) and place it back onto the hub. Use a hammer to lightly tap the hub back into place.


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