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.

[Zulfiqar]

the procedure is exactly the same as oldschool cars with a taper bearing set, with mercedes they provide a very nice and very elegant way to adjust the bearings so they can be adjusted even by the greenest novice.

The idea is to have a microscropic level of clearance as the hub sits perfectly flat. I have used a regular 6 inch long flat screwdriver to tighten the nut and also my fingers. the sweet spot is between the two points where the nut stops.

Dont go spending out for the green Fuchs branded grease, any grease with GC-LB rating from your parts store will be more than good.

[87tdwagen]

IMHO it is worthwhile to get to know this process by feel. Bearings are a maintenance item, that only need replacement when worn or damaged. It is expected that they be routinely cleaned, repacked and adjusted, with interim adjustments in between.

A simple 2 pieces cone shaped bearing grease packer and wheel bearing grease is about the only special tools needed. Properly maintained you should get a long usage from them. My w124 front bearings are original with 310k miles on them, no issues. They get pulled and packed every 150k miles. The same has held true for most all old school cars ever I have ever owned.

Many good methods documented, chooose what's best for your abilities and comfort level.

[Diesel911]

I have been working on the old school cars I owned since the late 1960's and the Mercedes is the only one, I managed to over tighten. I drove 2 blocks and check for heat, and I had indeed overheated enough to roast the grease inside of the hub.

I had to do the job over again to get out the roasted grease and I had to spend what was I remember 2 hours finding all of the stuff to get to gather one dial indictor and base set (which I had not used or seen together for like 12 years).

When I used the dial indicator with the factory instructions, I had no issues at all and never any issues when I used the indicator all of the other times, I had the hubs off. So, I can personally say that if you use dial indicator, I has zero problems.

I even finally bought a metric dial indicator.

[Sugar Bear]

Yes, wheel offset affects bearing loads/pressures. I run a trailer with a sealed bearing cartridge on which the axle manufacturer clearly states only zero offset wheels may be used. I think zero is needed in my case because both bearings are in one sealed cartridge with virtually no distance between them. Our cars have some offset in the wheels from the factory and distance between the bearings.

Did some searching a while ago and found Valvoline gray wheel bearing grease has a high melting point and was readily available. Watched a test on a store brand grease, after seeing it I won't use it.

If you don't have the feel for bearing endplay a dial indicator is the way to go.

About putting a little extra grease on the hub wall, it can prevent grease from walking up the taper of the hub toward the inner bearing leaving the outer bearing dry. In the mid 70's GM had trouble with this on their small cars. They added a stop/ledge to the hubs to prevent this which then required a special tool to remove the outer race because the stop/ledge was in the way of a straight punch.

If the old bearings look good re-use them...save the old time quality.

Good luck!!!

[Diesel911]

Definitely the person working on the cars choose what method to use to adjust the bearing end play/clearance.

Someone needs to do it by hand and after that check with the dial indicator and see what they came up with.

I have been trying to find where he posted but an older member dmmorrison apparently worked in a shop and he ask his guys to adjust the clearance by hand and checked with an indicator and his comment was done by hand mostly resulted in too loose.

If you ever have to do the rear wheel bearings the dial indicator is much more critical.

[Diesel911]

I found this: Post 11.
"ou're welcome. I learned the hard way. The last time I had the front rotors replaced on my 300SD, I took it to a local shop (not an MB specialized shop). The second time I took it there (with the first set of replacement wheel bearings and grease tube in hand and original set howling at every curve), I walked through the procedure with the tech and left the manual open on the passenger seat for him. Two weeks later (2kmi) I ended up installing the second set of replacement wheel bearings at home. Never another problem. Lesson learned: Don't take the German iron to the local shade-tree mechanic done good.

This is not rocket science, but those procedures were written for a good reason and they work. Why try to deviate?"

Of course, it was not the guy working on his own car doing the feeling of the end play.

Wheel Bearing Adjustment

[Texasgeezer]

What is the 'best' amount of grease to add to inside of the seal?

I know at a minimum the rubber groove area of the seal should have grease.

But does adding more to the inside of the seal below the rubber grooves help even more?

It seems that a little more added there would possibly prolong the life of the seal and maybe provide a bit more for the large bearing.

Too much, globbed on, might put pressure on the seal when installed on the spindle.

What do y'all think?

One of the internet people said that he always installed his boat trailer seals backwards because he wanted to keep water from going into the hub.

This doesn't make sense does it? Seems it would the seal would fail sooner that way.

[Sugar Bear]

Turn the seal over and look into the groove, there is usually a spring in there that can get dislodged during installation. Pack that groove with enough grease in 3 points to prevent the spring from jumping out of position. Put a film of grease on the sealing surface so the seal doesn't run dry

No need to put anything on the outer edge of the metal seal body. The genuine MBZ seals are high quality.

Good luck!!!

[Texasgeezer]

Trying to go through the calculations for spindle nut movement from a properly seated hub. One spindle nut turn = 1 mm of movement.

If the factory spec is between .01 mm and .02 mm.

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 could 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 to be in the sweet spot. Or reworded turn it backward until it has moved 1/100 to 1/50 of a spindle nut rotation. That's very difficult to estimate by feel or eyeball.

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. That's a pretty big movement away from proper setting.

Am I off in my calculations?

[Zulfiqar]

pack some grease into the spring cavity of the seal and hammer it home after installing the inner race and bearing into the hub.

You can then install the remaining of the required 70 grams of grease into the empty cavity of the hub and finally the bearing.

dont guesstimate the motion of the nut to measure how much you are clearancing the bearings, This is an acquired skill. You first have to use a wrench to crank down the center nut while jiggling or spinning the hub to fully seat the bearings.

then back off by a turn, smack the center of the spindle axle with a hammer to jar the hub loose again, and then advance the nut to set the clearance.

I have used a method of using a screwdriver to spin the nut and noting where it stops, then backing it off and then using my finger and thumb to spin the nut and noting where it stops.

The adjustment is usually about 1/3 to 1/2 of the way in between those two. I have driven my old cars on this setting for tens of thousands of miles without issue.

If you have never done this, try it a few times on a wheel, or use a dial caliper if you absolutely need to be perfect. and use a comfortable sitting position so you are not stressing yourself.

tip, if you are replacing grease with anything other than the lithium complex grease required, then please wash the hub thoroughly with a strong soap like purple power and hot water after you have cleaned it with solvent. This removes all traces of old grease.

[Texasgeezer]

If the calculations that provide the degrees out of 360 for the sweet spot are correct at 3.6 to 7.2 from the 'pushed in' zero degree position of being firmly seated, why couldn't a simple printed out degree wheel and a magnetic pointer attached to the spindle nut be used to get a very accurate setting? Might even be as accurate or more so than the dial meter measuring in and out movement. One full revolution would give 1 mm of clearance so 5.4 degrees of movement ( .015 mm ) from fully seated would be dead center of the desired range.

Looks to me like the known pitch of the thread 1 mm and measuring the degrees of spindle nut movement would be more accurate.

So it looks to me that what I can not be sure of is determining what is the ' properly seated, zero clearance ' position of the hub. Push it on firmly, screwdriver it on, wrench it on?

[vwnate1]

Here we go again..... .

These are standard tapered roller bearings, cup and cone, no special tools required but you *do* need to practice and get a feel for the job .

There's a simple tool that will properly pack the wheel bearings for you or you can learn to do it correctly, very few "mechanics" I've ever met understand this job and so use a bearing packer, a nifty low cost tool .

I posted up links to the you tube video of how to hand pack roller bearings, if you can't find it I'll go looking .

DO NOT FEAR THIS JOB ! .

[engatwork]

I always centerpunch the 12 o'clock position on the nut prior to breaking down to indicate where it was before starting job. Sometimes it winds back up at the 12 o'clock position.

[Zulfiqar]

Originally Posted by Texasgeezer

If the calculations that provide the degrees out of 360 for the sweet spot are correct at 3.6 to 7.2 from the 'pushed in' zero degree position of being firmly seated, why couldn't a simple printed out degree wheel and a magnetic pointer attached to the spindle nut be used to get a very accurate setting? Might even be as accurate or more so than the dial meter measuring in and out movement. One full revolution would give 1 mm of clearance so 5.4 degrees of movement ( .015 mm ) from fully seated would be dead center of the desired range.

Looks to me like the known pitch of the thread 1 mm and measuring the degrees of spindle nut movement would be more accurate.

So it looks to me that what I can not be sure of is determining what is the ' properly seated, zero clearance ' position of the hub. Push it on firmly, screwdriver it on, wrench it on?

I'll try finding the old Mazda RX7 repair manuals I had. They mentioned using a weight of a specific weight, I think it was the cars lug nut and a specific length of string. it was setup as a plumb bob, the weight of it and how easy it spun from 3 to 6 o clock set the preload. Quite interesting and cheap, old mazda service manuals were like that.