PeachParts Mercedes-Benz Forum - View Single Post - My Differential Pinion Has Almost No Preload (Replacing Seal)

Squiggle Dog · #14 03-28-2019, 01:08 PM

Yeah, the factory service manual shows what's essentially a torque screwdriver. The lb-in beam type torque wrench I have is suitable for the job, and is common practice. My area of concern was that the pinion bearings of the Ford truck differential had no preload (and may have been loose), and also that the pinion bearing friction in my 300SD's differential was almost not measurable due to having almost no preload like it was supposed to. I'm sure in both cases it's due to wear.

So, since the preload on my 300SD's bearings was too low, it led me to wonder what the correct preload would be since I can't use the previous setting as a reference (and I wouldn't have liked that method anyway, since there is no guarantee the setting is correct). And then the specifications in the factory service manual is with the gear set removed from the housing, not with it installed as mine is. Having the gear set in place no doubt adds friction, but how much I do not know.

So I think the most logical thing to do is set the preload so I am at the high end of the settings indicated for used bearings in the factory service manual, because 1. the bearings will not be as loose as they were before 2. they won't be too tight, and 3. they are likely to be in the correct range.

It would be nice to know if someone who has done these before has taken note of the friction on several different differentials which have the axle shafts removed but the gear set in place so they could give me a definite proper setting. But, I think going with my plan will suffice.