Front wheel bearing comments and questions

[Texasgeezer]

Spent a lot of time the past few days reviewing forum threads, videos, and searching the internet.

Finally convinced myself to order a good dial gauge setup to check the hub and bearing installation. It'll take about a week to get here.

It was really surprising to see so many different ways to perform this task. That's why I decided to try to do it by the book with my own decisions on how to handle the unexplained portions.

One video showed a bearing fresh out of the box with no grease just being pushed into a big circle of grease on the inner surface of the race.

Another showed the servicer coating the spindle with about 1/2" of grease for almost the entire length. Where is that grease going to go when the hub is installed? Possibly be pushed by the seal out of the hub.

Another showed a high mileage 600 series where the owner believed all he had to do was change the grease in the cap periodically. He had never removed the hub bearings for servicing. He believed the grease would magically flow from the hub to the interior and supply grease as needed for the two bearings.

One mentioned using a 3 lb hammer to ' help ' get the hub into position.

Most videos showed the servicer doing a hand tightening procedure without using a dial gauge.

Experienced forum members mentioned how they thought they could do it by feel but ran into problems later due to not using the dial gauge.

One commented that the centrifugal force would ' push ' the added grease inside the hub outward into the bearings and keep them lubricated.

What really convinced me to order the dial gauge and try to do it ' properly ':

- There seems to be a very narrow ' sweet spot ' for the adjustment. Too tight or too loose can cause problems such as:
Brake pulsing, uneven brake rotor wear, overheating, uneven race wear, failure sooner, increased tire wear, problems with alignment and even ABS sensor problems
- my method of counting the revolutions and using that to get back to original specs didn't seem to work. The hub had a much different feel when turning by hand. Don't know if it was the fresh grease, the new and tighter seal, or my count being wrong.


So if I was to do this task over I would:

- mark the left and right hub so they go back onto their original side
- mark the spindle end ' between ' ends of the spindle nut. I did mine by tapping a mark with a flat blade screwdriver.
- 'accurately' count the number of turns for the nut to clear the final thread. I should have been more careful with my counting. I counted 12 turns for the driver side and 11 & 1/4 turn for the right side. I thought since I didn't have a dial gauge this should allow the hub to be really close to the previous setting.
- remove the seal and bearings
- clean the bearings with an appropriate solvent, air dry without spinning the bearing by air pressure
- clean the spindle. Use soft abrasive like 0000 steel wool to clean the area where the seal rides and bearings ride. Clean with solvent and rag.
- put the bearing and grease into a clear plastic bag and work the grease into the bearing
- put close to the ' proper ' amount of remaining grease into the hub and smear it smoothly close to the inner race of each bearing. This should be similar and possibly better than what ' centrifugal force ' accomplishes. My old grease in the hub was still very clean looking but was still in a ' high glob ' in one area as if it been recently placed there and not 12 years before. Centrifugal force had not pushed it to coat the inside of the hub. Old grease did show shirinkage crack signs of ' drying out '
- smear a light coating of grease onto the spindle to help seat the hub and prevent corrosion
- install the bigger bearing into the hub
- smear a little grease on top of that bearing
- fill the bearing rubber seal grooves with grease plus a little grease inside past the rubber seal. Couldn't find any good writeup on how much grease for the seal.
- put the hub onto the spindle. Seat the big bearing by pushing with both hands firmly.
- coat the small bearing race with grease
- install the small bearing
- smear a coating of grease onto the outside of the small bearing
- install the special washer onto the spindle
- install the spindle nut and turn the number of turns that were counted during removal.
- spin the hub by hand several times to help evenly deposit the grease into the bearings
- if calipers and pads still installed, move the pads away from the rotor
- snug up the rotor with at least two bolts opposite each other to prevent play in the rotor. Use washers if lug bolts too long.

- then do the proper dial meter method to adjust the hub position

One thread with pictures for use of the dial gauge is: https://mbworld.org/forums/w211-amg/665555-wheel-bearing-end-play-check-adjustment.html

- Coat the hub's cap on the inside with the proper amount of grease and install

The minimum outward movement of the hub should be .01 millimeters/ 0.0003937008 or 4/10000 of an inch. The maximum outer movement of the hub should be 0.02 millmeters / 0.0007874016 or 8/10000 of an inch. That's a very small sweet spot. If I understand it correctly, you tighten the spindle nut snug against the fully seated spindle and then turn it backward until it's between 3.6 and 7.2 degrees of movement from that bottom position.

Turning the spindle nut backwards 1/4 turn or 90 degrees of rotation would put the adjustment out of spec by about 12 times the maximum limit set by the dial gauge.

If you disagree or have additional tips please respond.

I found one website that seems to have fairly accurate information about vehicles including wheel bearing info:

https://www.knowyourparts.com/technical-resources/hubs-bearings/bearing-adjustment/ Some info from reputable companies like Timken. If you ' click ' back on ' technical resources ' there are close to 18 different vehicle subject areas.


There were a few comments that installing wheels with an offset could significantly decrease wheel bearing life due to changing the angle of pressure on the bearings.

"Posting this before I'm finished with it to avoid losing it due to website automatically signing me out. This should prevent the loss of my entry before I'm finished" Wish they would change it to not sign someone out if they are posting.