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How to Replace Mercedes Benz Front Wheel Bearings
 
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Pelican Technical Article:

How to Replace Mercedes Benz Front Wheel Bearings

Steve Vernon

Time:

4 hours4 hrs

Tab:

$45

Talent:

****

Tools:

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

Applicable Models:

 
Mercedes-Benz 190E (1984-93)
Mercedes-Benz W124 (1986-95)
Mercedes-Benz W126 (1981-91)

Parts Required:

Bearing kit, high temp grease

Hot Tip:

Check the condition of the drive belt and the belt tensioner

Performance Gain:

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

Complementary Modification:

Replace brake pads and discs

An often overlooked part of most cars are the wheel bearings. 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. Symptoms of a failed wheel bearing are a continual low rumbling sound coming from the wheels that may or may not go away while turning in one direction. Replacing the bearings isn't a difficult procedure, but it does involve some specialized steps to ensure that it is done right. With that said, here's how you do it.

Begin by removing the front brake assembly as shown in Pelican Parts Technical Article on Replacing Your Brake Pads and Rotors. Once the calipers, pads and discs are removed, you'll have access to the wheel bearing hub. Remove the dust cap from the front of the wheel hub. In some cases, the hub will just gently slide off using a screwdriver against the lip as shown here. Sometimes, you may need to use a little penetrant spray around the outer edge and let it soak in to help ease it off.

With the hub dust cap removed, the axle nut sits at the center. It's a good idea to wipe off any excess grease on the nut. Use a 5mm hex socket 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 remove the nut from the spindle.

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 signs of discoloration or pitting. These are signs that the bearing is worn and requires replacement. Clean all the grease off the spindle and check it for wear as well. If the spindle shows any grooves, discoloration or pitting, you'll want to replace it.

With the wheel hub removed from the car, turn it over to the back side. You'll see an oil seal pressed inside. 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. It will take a fair amount of force to pry the old seal from the hub. 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 will likely destroyed as comes out. Once the old oil seal is removed, you can extract the rear wheel bearing from the hub. Take a look at the face of the needle bearings for any signs of pitting, scratching or discoloration.

Once the tapered wheel bearing is removed, 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, or in our case a 30mm socket will fit inside the bore. This helps to apply an even force to all sides of the race. Use a hammer to pound the race out of the hub. This will take a fair amount of force to drive out and is probably the hardest part of the job. For the larger race on the opposite side, you'll have to use a smaller socket 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. Take care not to damage or scratch the inside bore of the wheel hub. Just take your time.

Once both races are removed, clean the inside of the wheel hub and look for any wear on the inside. Like the spindle, if there are deep grooves, discoloration or pitting on the inside, replace the hub. Take the new inner bearing race and place it in the bore on the rear of the hub. You'll want to position the tapered section to accept the bearing. Make sure that you have the orientation correct before you begin to install the race.

Now drive the bearing race into the hub until it seats against the bottom flange of the hub. Typically, you would want to use a drift, however I found that a ball joint socket for a Porsche 911 is the same diameter as the race. Take your time and make sure that the race goes in straight. It's very easy to cock the race in the bore.

Before installing the bearing into the wheel hub, it's necessary to pack it with grease. The idea here is to fill all the open spaces of the needle bearings with grease. This will evenly distribute the grease throughout the bearing. There are a couple different ways of doing this. You can buy a wheel bearing packer, which uses pressure to push the grease in, or rotate the bearing back and forth while pushing grease in. It's a good idea to apply the grease a bit on the heavy side.

Be sure to also put a coat of grease on the face of the bearing race. 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 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 using a flat piece of metal or wood to ensure the seal does not get cocked in the bore on the wheel hub. Keep tapping the seal until it bottoms out in the bore.

Now turn the whole hub over and clean the mating surface for the outer wheel bearing race. Center the new race in the hub and carefully check that it is straight. Like the inner bearing race, you'll want to use either a drift or a socket to tap the outer race into the hub. Be careful not to cock the race in the bore when driving it in. Keep driving the race down until it hits the stop on the flange. Take care not to damage the tapered face of the race.

Coat the spindle with a good amount of high temp wheel bearing grease. In this case, we are using the factory applied grease from Mercedes-Benz. 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. Pack the front wheel bearing with the high temp grease like you did with the rear bearing. Like before, take your time and make sure that all the spaces in the bearing are coated evenly. Fit the bearing into the wheel hub. Keep in mind that the tapered section of the bearing fits into the race facing inward.

You'll now need to adjust the wheel bearing. There are two schools of thought of how to do this. One is to use a dial indicator mounted on the face of the wheel hub and measure the amount of lateral run out on the center of the clamping nut. The other is to thread the nut on the end of the spindle and tighten it until you can't turn the hub anymore. Then back the nut off until you can just turn the hub by hand. Then torque the 5mm bolt on the end of the nut.

If you use a dial indicator, set up the indicator to measure the lateral play (back and forth pulling on the rotor) while turning it. You'll need to tighten the spindle nut when the run-out measures between 0.01-0.02mm.

Like with the other method, torque the 5mm bolt on the end of the nut. The last step is to put a little of the high temp grease on the inside of the dust cap and place it back onto the hub. Use a hammer to lightly tap the hub back into place. All that's left to do at this point is to re-install the brake disc, pads and calipers and you're done.

Shown here are the contents of a front wheel bearing kit for one side of the car along with a tube of high temperature wheel bearing grease specifically for Mercedes-Benz.
Figure 1

Shown here are the contents of a front wheel bearing kit for one side of the car along with a tube of high temperature wheel bearing grease specifically for Mercedes-Benz.

Begin by removing the front brake assembly shown in our tech article on brake pad and disc replacement.
Figure 2

Begin by removing the front brake assembly shown in our tech article on brake pad and disc replacement. Once the calipers, pads and discs are removed, you'll have access to the wheel bearing hubs as shown here.

Remove the dust cap from the front of the wheel hub.
Figure 3

Remove the dust cap from the front of the wheel hub. In some cases, the cap will just gently slide off using a screwdriver against the lip as shown here. Sometimes, you may need to use a little penetrant spray around the outer edge and let it soak in to help ease it off.

Here is the hub with the dust cap removed.
Figure 4

Here is the hub with the dust cap removed. The axle nut sits at the center. It's a good idea to wipe off any excess grease on the nut. The red arrow points to the hex bolt which clamps the axle nut in place.

Use a 5mm hex socket to loosen the clamp on the axle nut (yellow arrow).
Figure 5

Use a 5mm hex socket to loosen the clamp on the axle nut (yellow arrow). Once loose, you should be able to easily remove the nut and washer from the spindle.

With the axle nut and washer removed, you will be able to pull the hub off.
Figure 6

With the axle nut and washer removed, you will be able to pull the hub off. As you do, the outer wheel bearing will pop out. There is a tapered roller bearing that fits inside a race pressed into the hub (red arrow). Check the bearings for any signs of discoloration or pitting. These are signs that the bearing is worn.

Shown here is the hub removed from the spindle.
Figure 7

Shown here is the hub removed from the spindle.

Clean all the grease off the spindle and look for any grooves or pitting.
Figure 8

Clean all the grease off the spindle and look for any grooves or pitting. If the spindle shows any of these, you'll want to replace it.

With the wheel hub removed from the car, turn it over to the back side.
Figure 9

With the wheel hub removed from the car, turn it over to the back side. You'll see an oil seal pressed inside. 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.
Figure 10

Use a seal puller to remove the old oil seal from the wheel hub. It will take a fair amount of force to pry the old seal from the hub. 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'll likely destroy it as comes out.

Once the old oil seal is removed, you can extract the rear wheel bearing from the hub.
Figure 11

Once the old oil seal is removed, you can extract the rear wheel bearing from the hub. Take a look at the face of the needle bearings for any signs of pitting, scratching or discoloration.

Once the tapered wheel bearing are removed, you'll have to remove the races that remain inside the wheel hub.
Figure 12

Once the tapered wheel bearing are removed, you'll have to remove the races that remain inside the wheel hub. The green arrow shows the race for the larger inner bearing while the purple arrow shows the race for the smaller outer bearing.

To remove the outer bearing race, you will need to use a drift, or in our case a 30mm socket will fit inside the bore.
Figure 13

To remove the outer bearing race, you will need to use a drift, or in our case a 30mm socket will fit inside the bore. This helps to apply an even force to all sides of the race.

Use a hammer to pound the race out of the hub.
Figure 14

Use a hammer to pound the race out of the hub. This will take a fair amount of force to drive out and is probably the hardest part of the job. For the larger race on the opposite side, you'll have to use a smaller socket 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. Take care not to damage or scratch the inside bore of the wheel hub. Just take your time.

Once both races are removed, clean the inside of the wheel hub and look for any wear on the inside.
Figure 15

Once both races are removed, clean the inside of the wheel hub and look for any wear on the inside. Like the spindle, if there are deep grooves on the inside or pitting, replace the hub. Shown here is the new inner bearing race. Make sure that the flange of the hub is perfectly clean before continuing.

Position the new race in the same orientation as the old one.
Figure 16

Position the new race in the same orientation as the old one. The tapered section of the race should face as shown in the photo here.

Now drive the bearing race into the hub until it seats against the bottom flange of the hub.
Figure 17

Now drive the bearing race into the hub until it seats against the bottom flange of the hub. Typically, you would want to use a drift, however I found that a ball joint socket for a Porsche 911 is the same diameter as the race. Take your time and make sure that the race goes in straight. It's very easy to cock the race in the bore.

Now take the high temp grease and coat the outside of the new bearing.
Figure 18

Now take the high temp grease and coat the outside of the new bearing.

Before installing the bearing into the wheel hub, it's necessary to pack it with grease.
Figure 19

Before installing the bearing into the wheel hub, it's necessary to pack it with grease. The idea here is to fill all the open spaces of the needle bearings with grease. This will evenly distribute the grease throughout the bearing. There are a couple different ways of doing this. You can buy a wheel bearing packer, which uses pressure to push the grease in, or rotate the bearing back and forth while pushing grease in. It's a good idea to apply the grease a bit on the heavy side.

Be sure to also put a coat of grease on the face of the bearing race.
Figure 20

Be sure to also put a coat of grease on the face of the bearing race. 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.

Shown here is the new oil seal that covers the rear wheel bearing.
Figure 21

Shown here is the new oil seal that covers the rear wheel bearing. Clean up any grease that may have gotten on the outer surface of the hub where the seal mounts and center it.

Carefully tap the oil seal into place using a flat piece of metal or wood to ensure the seal does not get cocked in the bore on the wheel hub.
Figure 22

Carefully tap the oil seal into place using a flat piece of metal or wood to ensure the seal does not get cocked in the bore on the wheel hub. Keep tapping the seal until it bottoms out in the bore.

Now turn the whole hub over and clean the mating surface for the outer wheel bearing race.
Figure 23

Now turn the whole hub over and clean the mating surface for the outer wheel bearing race. Shown here is the new race ready to be installed.

Center the new race in the hub and carefully check that it is straight.
Figure 24

Center the new race in the hub and carefully check that it is straight.

Like the inner bearing race, you'll want to use either a drift or a socket to tap the outer race into the hub.
Figure 25

Like the inner bearing race, you'll want to use either a drift or a socket to tap the outer race into the hub. Be careful not to cock the race in the bore when driving it in. Keep driving the race down until it hits the stop on the flange.

Coat the spindle with a good amount of high temp wheel bearing grease.
Figure 26

Coat the spindle with a good amount of high temp wheel bearing grease. In this case, we are using the factory applied grease from Mercedes-Benz, available from Pelican Parts.

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 27

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.

Pack the front wheel bearing with the high temp grease like you did with the rear bearing.
Figure 28

Pack the front wheel bearing with the high temp grease like you did with the rear bearing. Like before, take your time and make sure that all the spaces in the bearing are coated evenly.

Fit the bearing into the wheel hub.
Figure 29

Fit the bearing into the wheel hub. Keep in mind that the tapered section of the bearing fits into the race facing inward.

This picture shows the setup of a dial indicator on the wheel hub if you use this method to adjust the bearing run out.
Figure 30

This picture shows the setup of a dial indicator on the wheel hub if you use this method to adjust the bearing run out. The other is to thread the nut on the end of the spindle and tighten it until you can't turn the hub anymore. Then back the nut off until you can just turn the hub by hand. Then torque the 5mm bolt on the end of the nut. Put a little of the high temp grease on the inside of the dust cap and place it back onto the hub. Use a hammer to lightly tap the hub back into place. All that's left to do at this point is to re-install the brake disc, pads and calipers and you're done.

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Comments and Suggestions:
Tx26 Comments: I have a dial indicator with a vice grip clamp used to check rotor runout, but not the magnetic stand. Can I still use it to measure bearing play and where to connect it to?
September 21, 2016
  Followup from the Pelican Staff: Attach to the spindle with the vise grip, then measure at the rotor hub. - Nick at Pelican Parts  
DM190E Comments: Is an alignment needed after this job?
August 31, 2016
  Followup from the Pelican Staff: Only if you have tire wear issues. - Nick at Pelican Parts  
Niamey Comments: How much grease should one use for one side? Is one tube of the MB grease enough for servicing both front wheel bearings? Thank you for the detailed description!
November 26, 2014
  Followup from the Pelican Staff: I have never measured the exact amount, as I usually work from a tub. However, you want to start at one end of the bearing and fill it until grease comes out the opposite side. - Nick at Pelican Parts  
T 91 190E 2.6 Comments: So I had this Job done by Canadian Tire store in my area and when I received the car it was making a grinding noise. I don't think they test drove it more than a mile because that's when the noise started, it has not stopped. I brought it to another shop and they could not figure it out either. The rotor on the driver side is touching the caliper mount. Do you guys have any remedies for me . I'm not sure if they installed new races. Thanks.
October 24, 2014
  Followup from the Pelican Staff: If the rotor is hitting the caliper, you have the wrong rotor or bearings. I would have them double check the part numbers that were used. - Nick at Pelican Parts  
280EZrider Comments: Just in case you don't have access to Porche special tools, you can use the old race on top of the new race to pound it into place. Also on MB cars the hub-nut cap should be filled to the crease of the cap with the same hi-temp bearing grease.
June 26, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
BIGGREDDSBABYBENZ Comments: Thank you SO much for these Tech Articles!!! I was never much of a wrencher until I got my baby Benz, and I started working on it myself out of necessity combined with bullheadedness... I was sick of giving othernot always honestpeople money to do things that I knew I could do if I just had a little guidance... Enter Pelican Parts!!! I started small, just replacing rear brake pads, then rear shocks, and today I just replaced my front wheel bearings!!! These are definitely the most intuitive tutorials out there... They not only helped me save money, which in turn I was able to invest back in parts, but built a real personal connection that I wouldn't have had otherwise... Keep up the good work and thank you again!!!
April 8, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
rbmacp Comments: Should the seal on the inner bearing sit flush with the hub, or is it OK if it bottoms out but still sits slightly above the edge of the hub? The seal that came out of the car sat flush, but the replacement seal sits higher - the inner lip of the hub measures 10.64mm, and the new seal measures 13.5mm
December 27, 2013
  Followup from the Pelican Staff: See attached photo. The seal should be installed until it stops moving (bottomed out). - Nick at Pelican Parts
malbuddy Comments: and by the way.. my assembly did not include a washer.. only the nut at the end of the spindle.. should there be a washer per your instructions?
November 5, 2013
  Followup from the Pelican Staff: Not sure what vehicle you have. It may or may not have been left off during a previous service. Give our parts specialists a call at 1-888-280-7799, they can help you determine if you should have one. - Nick at Pelican Parts  
malbuddy Comments: Thank you ever so much for the write-up. It has helped tremendously. One simple question if I may. Concerning the very last step of threading the nut on the end of the spindle. When you tighten the nut until the wheel will not spin and then back off until it can be rotated by hand, how free is this hand rotation? Does backing off until able to rotate by hand mean there is still a good bit of friction using a bit of force to rotate or the should the rotator spin easily with little friction? Thanks to your instructions, I feel confident the job is done properly - all except this last little bit.

November 5, 2013
  Followup from the Pelican Staff: Check bearings by hand is to be left to the experienced. There is a fine line between loose, tight and just right. Personally, I always use a dial indicator, it is the only way to be sure it is 100% correct and will not be a come back.

using a dial indicator, tighten nut until rotor turns with resistance. Preload dial indicator to 2 mm. Adjust bearing preload until axial play is between 0.01 -0.0 2mm. Note the small spec, can you feel that by hand?- Nick at Pelican Parts
 
Stan Comments: How do you get the bearing housing off if its sealed on
June 28, 2013
  Followup from the Pelican Staff: I assume the hub is stuck on the spindle.
When this happens; I put the lock nut back on about half way to keep the outer bearing partially in place (so the hub doesn't tilt to far damaging the spindle threads), use a hammer to "lightly rap" on the back of the hub while rotating it, usually the vibration frees the bearing race.

If this fails, you may need to rent/buy an "axle hub press" or large three jaw puller to remove it, then work on separating the inner bearing race from the spindle.

Here are examples of the type of tool I use to remove stubborn wheel hubs.

http://www.pelicanparts.com/Mercedes-Benz/catalog/ShopCart/TOOL/POR_TOOL_WTD181_pg21.htm

http://www.pelicanparts.com/Mercedes-Benz/catalog/ShopCart/TOOL/POR_TOOL_WTD181_pg22.htm

-whunter-
 
Marcoyodog Comments: And also, is there any real advantage to using the Mercedes-Benz grease? I have a jar of Mobil 1 synthetic grease that I was planning on using.
May 6, 2013
  Followup from the Pelican Staff: In my opinion; any top quality bearing grease is equal to the MB grease.

whunter@pelicanparts.com
 
Marcoyodog Comments: Excellent write-up. I plan to knock out the front bearings on the 190 soon, so definitely helpful.
May 6, 2013
  Followup from the Pelican Staff: Thank you.
Glad to know it helped you.
whunter@pelicanparts.com
 
French eric Comments: Very very good info...
May 1, 2013
  Followup from the Pelican Staff: Thanks, glad it helped you.
whunter@pelicanparts.com
 

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