'91 190E 2.3 wheel bearing endplay
 

Looking for front end looseness, I noticed more slop in the left front wheel bearing than the right. I tried to adjust it out using the Haynes method, which is '...you should just feel the freeplay when moving the rotor axially by hand' or '...you can rotate the backing washer smoothly with minimal force using one finger'. Either way, I can feel freeplay still when shaking at 12 and 6, as much as I had before. If I adjust so it is stiff to turn the washer using 2 fingers, I remove the freeplay when I shake it.

What is the preferred non-gauge method for adjusting this, and am I needlessly concerned about removing the freeplay? The car has about 90k miles, and there is some vibration on some freeway surfaces. I am tackling the problem by eliminating the non-wheel/tire possibilities first. Thanks.

Steve

Take off the dust cap. Loosen the retaining bolt on the nut. Now turn the nut until there is 0 play in the hub, but NO PRELOAD!!!!

This is crucial. There can be no preload on the bearings or they will fail.

Thanks, Donnie! That was my instinct, as it is the technique for our m'home. I just didn't feel right assuming the same technique works for a 1.5 ton vehicle as a 5 ton one. I'll re-adjust.

Steve

Interesting. I have a 98 202 (C class) that was experiencing some high speed steering vagueness, and it turned out to be a combination of loose front end bearings, worn steering damper, and incorrect alignment. My dealer was kind enough to share the factory spec sheet, which calls for an axial endplay of .01-.02 mm. This is 4 to 8 ten thousandths, which is a pretty small measurement. I have a dial indicator, and set it correctly, but I noticed that this measurement is arrived at if you tighten the nut with light finger pressure. When set correctly, you can just barely get motion when rocking the wheel installed. and I can;t feel anything from the rotor if I try to wiggle the rotor with the rotor on, but the wheel off. Light finger pressure seems to work. And as said, if these are pre-loaded, they will overheat and fail.

Thanks for the input, Dave. Every little nuance helps when attempting an adjustment based on subjective tactile feedback!

Steve

P.S. I AM going to try to remember to bring a dial indicator home from work, but at this point the free time to tackle the job again will be lacking for awhile.