Repacking front wheel bearings/adjustment - PeachParts Mercedes-Benz Forum

warmblood58 · #1 03-17-2010, 06:26 PM

Hi! I am going to replace the front rotor on my '84 123 wagon and short of using a micrometer setup, what is the best way (accurate) way to adjust load on bearings after packing? Thanks!

Diesel911 · #2 03-17-2010, 06:48 PM

Quote:

Originally Posted by warmblood58

Hi! I am going to replace the front rotor on my '84 123 wagon and short of using a micrometer setup, what is the best way (accurate) way to adjust load on bearings after packing? Thanks!

That would be to follow the Factory Service Manual and use a Dial Indicator.

After installing new Rotors I tried doing mine by hand and after several miles down the Road I found I had overheated the Grease inside of the Hubs.
I had to pull everthing apart clean out all the roasted Grease and re-pack with new Grease.
After that I spent several hours finding where I put my Magnetic base and Dial Indicator that I was too lazy to look for in the first place. I adusted the end play as per the Factory Service Manual and over 2 years has gone buy with no problems.
In my case I only created more work for myself by not doing it the correct way.
I have owned Cars since 1968 and had always adjusted the Wheel Bearing Clearance by hand and had no problems with that on other Cars. That is why I did not believe it had to be done with a Dial Indicator on the Mercedes.
If you do use another method to adjust the End Play I would suggest that when you drive the Car only drive a few Blocks and get out and put your hands on the Front Wheel to see if it is hot. Get in and Drive some more and do the same until you are sure it will not over heat.

jimandsuzy · #3 03-17-2010, 08:36 PM

I'm running a test on wheel bearing adjustment on my 85 300SD. I have set one wheel the book way, with micrometer, the other wheel I set the american way, snug up with a wrench then loosen and then tighten using one finger and thumb. So far no difference but only have about 3000 miles. The reason I am doing this is because the MB wheel bearings I use are made by an american company for many different applications. If the bearing goes into an american car guess how the mechanic does the adjustment? I don't believe the bearing knows when it's in an MB and thus the micrometer adjustment, while very accurate, is not necessary. If my assumption about the bearing knowing which car it's in is wrong please correct me.

vstech · #4 03-17-2010, 08:41 PM

don't forget this difference between MB and "the american way"...
american cars use a castle nut with only a few notches in them... ya gots to loosen the nut until the cotter pin lines up with the notch in the castle nut...
with MB you adjust the nut to the proper end play, and then LOCK IT IN THAT POSITION EXACTLY. my guess is all american way nuts are really set very loose, and MB get's it JUST RIGHT.
there is no way to do it "the american way" on an MB...

leathermang · #5 03-17-2010, 08:54 PM

Quote:

Originally Posted by warmblood58

Hi! I am going to replace the front rotor on my '84 123 wagon and short of using a micrometer setup, what is the best way (accurate) way to adjust load on bearings after packing? Thanks!

Do you know how much it costs to get a dial indicator and mag base so you can do it correctly ?

vstech · #6 03-17-2010, 08:58 PM

I think Harbor freight has the base for 6.00 and the dial in MM is like 12.00 I'll go look....
15 for base.
12 for dial
http://search.harborfreight.com/cpisearch/web/search.do?keyword=magnetic+base&Submit=Go
http://search.harborfreight.com/cpisearch/web/search.do?keyword=dial+indicator&Submit=Go

jimandsuzy · #7 03-17-2010, 09:10 PM

I agree the american way sets the bearing looser than MB. American cars don't have wheel bearing problems so I say again, how does the bearing know it's in a MB?

tangofox007 · #8 03-18-2010, 09:36 AM

Quote:

Originally Posted by jimandsuzy

I agree the american way sets the bearing looser than MB. American cars don't have wheel bearing problems so I say again, how does the bearing know it's in a MB?

That's an excellent question. The difference is the nut. The typical domestic vehicle uses a nut with zero drag, so it's easy to "feel" the proper adjustment. The MB clamping nut makes adjustment by feel impossible.

Brian Carlton · #9 03-17-2010, 10:01 PM

Quote:

Originally Posted by warmblood58

Hi! I am going to replace the front rotor on my '84 123 wagon and short of using a micrometer setup, what is the best way (accurate) way to adjust load on bearings after packing? Thanks!

You cannot set the bearings on a M/B without a dial indicator. I've done it both without and subsequently with, and the results are wildly different.

Forget about it.

jimandsuzy · #10 03-17-2010, 10:04 PM

I've done it without a dial indicator and no problems so far.

vstech · #11 03-17-2010, 10:06 PM

Quote:

Originally Posted by jimandsuzy

I've done it without a dial indicator and no problems so far.

careful, Murphy will get ya!

leathermang · #12 03-17-2010, 11:29 PM

Quote:

Originally Posted by jimandsuzy

I've done it without a dial indicator and no problems so far.

That statement does not make you look very smart. You could have said nothing and just watched what long time MB people who own and read the MB instructions post for advice. You told the original poster NOTHING about the specifics of how you did such a good job without the dial indicator... and how are we supposed to know whether you just got lucky.... that is a possibility... but of NO help to the long range situation of the original poster since he has no way to reliably duplicate your luck.

vstech · #13 03-17-2010, 11:35 PM

Quote:

Originally Posted by leathermang

That statement does not make you look very smart. You could have said nothing and just watched what long time MB people who own and read the MB instructions post for advice. You told the original poster NOTHING about the specifics of how you did such a good job without the dial indicator... and how are we supposed to know whether you just got lucky.... that is a possibility... but of NO help to the long range situation of the original poster since he has no way to reliably duplicate your luck.

I just went back and read all the posts since the OP...
none of us answered the question...
we've mentioned the FSM, and stressed how important/unimportant it is to follow their method... none of us have given the OP actual information to use on their car... well except me, and the only info I gave is the price of the tools he/she will need.
I believe BC has posted in the past the exact specs for this job, so a search of wheel bearing in brian's posts should turn up the info...

Diesel911 · #14 03-17-2010, 11:14 PM

I think a better test might be to do it several times by hand and to see if you can duplicate the same clearance/end play each time. That would give a better indication if it is a good idea or not.

Using the Dial Indicator you can always get it correct.

Then there is the simple question is it an inprovment to make the adjustment without the Dial Indicator?

If you do not have a Dial Idicator or simply do not want to buy one or use one as a matter of choice; you do the best you can.

Just as an addition some cars (like the 1970 Toyota Corona) you actually pre-load the wheel Bearings. You turn the nut in untill it stops and then rotate the nut x degrees or in some cases x number of flats on the nut. Toyota also uses the same Bearings.

Brian Carlton · #15 03-17-2010, 11:30 PM

Quote:

Originally Posted by Diesel911

I think a better test might be to do it several times by hand and to see if you can duplicate the same clearance/end play each time. That would give a better indication if it is a good idea or not.

BTDT.

You can't.