wheel bearing repack - PeachParts Mercedes-Benz Forum

opossum · #1 11-22-2003, 10:27 AM

Hello everyone,
I'm about to do a front end brake job and figured I'd repack the bearings while im at it. I just bought a manual but it isnt here yet. So, I'm just diving in. The brakes I've done before..no biggie. The bearings, Is there anything I need to look out for or any tricks to make this a little easier? I have new seals ready to go. This is going to be on the 89 190e.
Thanks in advance,
O

Kestas · #2 11-22-2003, 12:29 PM

First, remove the rotor and hub unit off the spindle. Clean ALL grease from the parts, including the spindle, then dry. Your workspace should be clean and grit-free to handle the bearings one they're clean.

Inspect the bearings. Raceway surfaces should be free of color from heat, no nicks or dents, and should still have some honing marks visible. They should be close to perfect.

When regreasing, pack the taper roller by placing a dollop of grease in the palm of one hand, and scraping it into the spaces between the rollers until full. Butter all the hub interior cavity surfaces with grease. Place both inner and outer raceway into the hub and add grease to the sides. Install grease seal.

Make sure you use a quality grease, typically a lithium-based NLGI 2 grease with EP additives for high temperature applications. Don't go too happy with the grease, since too much will reduce thermal transfer properties, thus reducing life of the grease and bearing.

Once everything is assembled back on the spindle, rotate the hub while wrenching down on the hub nut. This'll seat the components and squeeze the excess grease from the bearing running surfaces. Wrench down until it's difficult to turn the hub. Then back off the hub nut until slack.

Set the hub nut for proper axial play according to specifications. It's best to use a dial gauge for this. If you go by feel, as some of us do, gingerly tighten the hub nut until axial play disappears - no more. You have to develop a good feel for this. You can't just wrench the nut down, or else you're sure to get early failure.

opossum · #3 11-22-2003, 01:09 PM

thanks Kestas,
That is a great help. I am of course having a hard time getting the blasted rotor off though! I'm about to try the torch technique if the penetrating oil hasnt done it's job yet..

opossum · #4 11-22-2003, 02:07 PM

Ok,
it all looks good from here. My new question is: How do I get the stinkin bearing seal out? Brute force? Also, How do you tell if your bearings are spent? They felt ok before I took em out but they seem to have a little play and slight coloration on the bearing surfaces. Im using a general purpose high heat valvoline grease. The red stuff that says it is good for european cars and wheel bearings,..Is that OK? It isn't lithium but it is what I have on hand.
thanks again.

#5 11-22-2003, 04:50 PM

Mercedes have a special high-temperature anti-friction grease that comes in a 150g. package which is just the exact amount to do both front wheels.

Not everyone uses it but it's highly recommended. The part number is A 001 989 23 51 10 (or at least that's what it used to be).

Kestas · #6 11-22-2003, 06:06 PM

Yes, the seal is a bear to get out. I mentioned a few things to look for while evaluating the bearing. There's no way to tell if it's spent. It either looks good, or it's not fit for further use. Where is the play you felt? Anything darker than a light straw color indicates heat damage and the bearing should be replaced. They are replaced as a set. (There are two sets of bearings on each front wheel).

As long as the grease you have has EP additives, you should be okay. For the anal-retentive, Mobil synthetic is a good grease, if you can get it. There's a new grease that just came on the market that is superior to Mobil synthetic. It's called Exxon Infinitec - much more water resistant. I'm not sure where you can get it. I have an inside track for these greases.

opossum · #7 11-22-2003, 08:36 PM

thanks guys,
the play is just a general-in every direction type of play. They just weren't tight,,ya know? I figured a little is normal, so I put everything back together. The color was definitely darker than straw..maybe a dark straw. I probably should have put new ones but I'll just ride on these for a week and see if they make any noise..If so, I could bust it out quick next saturday now that I know what I'm doing. It sure feels good to have it done though and it rides better already for sure.
thanks for all your help, you rock! Have a good thanksgiving!
O

Mike Murrell · #8 11-22-2003, 09:48 PM

I haven't pulled MB grease seals yet, but the following works on a multitude of domestic and asian cars; it may also help with seal removal on european cars.

http://www.lislecorp.com/tools/catalog/bearings/index.htm

This tool and the bearing repacker shown below it are available at many auto parts stores. Pep Boys carries a line that Lisle likely makes. Other mass-marketer parts houses carry a line of specialty tools shown at the Lisle site under their or Lisle's name.

opossum · #9 11-22-2003, 10:03 PM

man,
some of those would have made my job alot easier today. The trick I learned w/o them (and hours of frustration) was to take an old flat head screwdriver and hammer and carefully but forcefully deform the edges of the seal inward to reduce surface area between the seal and its home, apply penetrating oil and let it sit. Then, with a wooden dowel and hammer tap the bearing out from the other side. It seems a little neanderthal but it worked. By the time I got to the other wheel I felt like a pro and it only took about an hour total. Brake job included.