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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 100,000 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.

Clean up any grease that may have gotten on the outer surface of the hub where the oil seal fits and center the seal in the bore.
Figure 14

Clean up any grease that may have gotten on the outer surface of the hub where the oil seal fits and center the seal in the bore. Carefully tap the oil seal into place taking care that the seal does not get cocked in the bore on the wheel hub (red arrow). Keep tapping the seal until it bottoms out in the bore. BE SURE TO INSTALL NARROW RUBBER SIDE OUT AS SHOWN DURING REMOVAL IN FIGURE 5! (Figure 14 photo is backwards.)

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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Comments and Suggestions:
likesoldstuff Comments: Figure 14 shows the inner wheel seal being installed backwards. If installed this way, seal will bind and expander spring will become dislodged! Be sure and install narrow rubber side OUT as shown when old seal is being removed in Figure 5!
May 1, 2016
  Followup from the Pelican Staff: Thanks for catching that. We appreciate it. I will have the article updated.
- Nick at Pelican Parts
 
82 sportsc Comments: Please upload seep 14 re the inner seal
Thanks for great article
January 1, 2016
  Followup from the Pelican Staff: Thanks for the note. We appreciate it. I will have the article updated. - Nick at Pelican Parts  
82 sportsc Comments: There still is no figure 14 for the inner seal install.
Please include and thanks for great article
January 1, 2016
  Followup from the Pelican Staff: Thanks for the note. We appreciate it. I will have the article updated. - Nick at Pelican Parts  
Rich Comments: It's a 1985 911 - yes I had to separate the lines.

Thanks
July 10, 2015
  Followup from the Pelican Staff: Thanks for the follow up. - Nick at Pelican Parts  
Rich Comments: Hi
I am in the middle of Frt bearing replacement and I can't seem to figure out how to remove the Frt caliper without disconnecting the brake line. The tech article says there are removable clips that free the brake line, thus allowing the caliper to be gently put to the side without ruining the hard line. The upper connection has such a clip, but the lower the one connecting to the strut does not. I can disco the line and bleed the system afterwards, but I was hoping not to have to do that.

Thanks for any insights
June 28, 2015
  Followup from the Pelican Staff: What vehicle are you working on?

The clip shown in the photo can only be removed if the brake lines are separated. - Nick at Pelican Parts
 
SpawnyWhippet Comments: Great article, but Figure 14 is missing. I believe this should be the installation of the new inner seal, which is not mentioned in the article.
June 3, 2015
  Followup from the Pelican Staff: Ah, good catch. I will have the image uploaded along with step 14. I apologize. - Nick at Pelican Parts  
78 PB 911SC Comments: I use a posi-lock model 104 gear puller with a slide hammer to get my dust caps off. I see they are a little pricy now got mine 25 years ago.
February 18, 2015
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Jim King Comments: Comments: I just finished replacing the front bearings on my 1988 Targa. The hardest parts were:
getting the dust cap off. Rocking with vise grips or channel locks just doesn't cut it. I had to use to claw hammers, with one hammer used to drive the claws of the other hammer into the groove on the dust cap. Doing this from opposite sides eventually removed the cap. Not very elegant and there has to be a better way! Comments and suggestions please.
Getting the inner bearing race out is difficult. I drove the race out using a long 3/8 inch ratchet extension and a hammer. This worked, but required an uncomfortable amount of hammering. When removing the inner race from the second hub, I first thoroughly cleaned the hub to remove all oil and grease, and then heated the hub to 300°F in the house oven for two hours. The removal of the second race when the hub was heated was then very easy using a drift and hammer. Heating the hub to 300°F and also cooling the race in the freezer made installation of the new race very easy. I used a large three-quarter inch drive socket with an OD just slightly smaller than the OD of the inner race to drive the race home into its seating. Installation was a piece of cake.
I did have some problems getting the hub with new bearings and rotor back onto the spindle. It transpired that the inner bearing was not sitting snugly in the inner race which made it impossible to get the hub onto the spindle. Make sure the greased inner bearing is sitting snugly in the inner race before presenting the hub to the spindle.
It would be useful to have the spec for torquing the locking nut, or an alternative to several posts which suggest that all is required is some minor movement in the thrust washer between the locking nut and the bearing. Is it possible to define the bearing setting by tightening the locking nut and then backing off 1/8 of a turn, one quarter of a turn, or whatever is appropriate? I have seen this type of instruction in other German manufacturers manuals.
August 13, 2014
  Followup from the Pelican Staff: When adjusting. I have always loosened the clamping screw, then loosened the bearing nut by 1/4 turn. Next, rotate the brake rotor while tightening the bearing nut in small increments. Keep doing this until washer can barely be moved back and forth using a small flathead screwdriver. - Nick at Pelican Parts  
Jim King Comments: I just finished replacing the front bearings on my 1988 Targa. The hardest parts were:
getting dust Off. Rocking with vise grips or channel locks just doesn't cut it. I had to use to claw hammers, with one hammer used to drive the clause of the other hammer into the groove on the dust. Doing this from opposite sides eventually removed the. Not very elegant and there has to be a better way! Comments and suggestions please.
Getting the inner bearing race out is difficult. I drove the race out using a 3/8 inch ratchet extension and a hammer. This worked that required an uncomfortable amount of hammer blow. When removing the inner race from the second-, I thoroughly clean the hub to remove all oil and grease, and then heated the hub to 300°F in the house of for two hours. The removal of the race when the hub were seated was then very easy using a drift in hammer. Eating the hope to 300°F and also calling the race in the freezer made installation of the new race very easy. I used a large three-quarter inch drive socket with an OD just slightly smaller than the OD of the inner race to drive the race home into its seating. Installation was a piece of cake. I did have some problems getting the hub with new bearings and rotor back onto the spindle. It transpired that the inner bearing was not sitting snugly in the inner race which made it impossible to get the hub onto the spindle. Make sure the greased inner bearing is sitting snugly in the race before presenting the hub to the spindle.
It would be useful to have the spec for torquing the locking nut, or an alternative to several posts which suggest that all is required is some minor movement in the thrust washer between the locking nut and the bearing. Is it possible to define the bearing setting by tightening the locking nut and then backing off 1/8 of a turn, one quarter of a turn, or whatever is appropriate? I have seen this type of instruction in other German manufacturers manuals.
August 13, 2014
  Followup from the Pelican Staff: When adjusting. I have always loosened the clamping screw, then loosened the bearing nut by 1/4 turn. Next, rotate the brake rotor while tightening the bearing nut in small increments. Keep doing this until washer can barely be moved back and forth using a small flathead screwdriver. - Nick at Pelican Parts  

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