Pinion Bearing Shims: An Alternative plus OEM Part Numbers

[lakesurfer]

Pinion Bearing Shims: An Alternative plus OEM Part Numbers

My project required me to replace the flange yoke on my differential, plus I upgraded to a Quaife ATB differential unit. These required adjusting my pinion depth to regain a good contact pattern between the pinion and crown gears. Pinion depth is adjusted via shims under the rear pinion bearing race. AFAIK, there is no "kit" of various sizes that can be ordered from MB or any of the usual suppliers. In fact most of the individual part numbers are approaching unobtainium status.

NOTE: I am using the differential from a 1978 350 SL/C in my project. It is my *belief* that the parts here would apply to all three differential types used across the years of the 107, and possibly other chassis types. However, do your own due diligence. Niemoeller is a great resource for connecting diagram illustrations to actual part numbers. That said, here is an inexpensive and commonly available kit that I am going use instead and was excited to find for your consideration:

Polaris Gearcase shim kit, p/n 3233581 (~$40 from Amazon, eBay, and various Polaris dealers)

ID: 63.44 mm (essentially matches my OEM MB shim)
OD: 78.73 mm (vs. OEM OD of 82.29 mm as measured on mine.)

NOTE: The smaller OD still covers 100% of the flat surface of the race, which seems to me to be the load bearing portion. I am using a slice of pool noodle to keep the Polaris shims centered while pulling or pressing the race in. Then, with 180+ NM of torque on the final assembly, I doubt they will wiggle.

Thicknesses I measured in my kit: 0.25 mm, 0.62 mm, 0.74 mm, 1.05 mm, 1.13 mm, 1.22 mm, 1.26 mm, 1.36 mm, 1.42 mm, 1.51 mm

The attached photos show the shim kits (2 views), the Polaris shim over my MB OEM shim, the Polaris shim over the pinion bearing race, and the assembly I used to pull in the race with the pool noodle helper to keep the Polaris shims centered.












Lastly, as a reference, I finally found the MB part numbers for the original shims, courtesy of https://www.niemoeller.de/en/w107/w107/B023/9/23 :

OEM p/n ; Thickness
1163531152 1.5 MM
1163532152 1.6 MM
1163532352 1.7 MM
1163532552 1.8 MM
1163532752 1.9 MM
1163532952 2.0 MM
1163533152 2.1 MM
1163533352 2.2 MM
1163533552 2.3 MM
1163533752 2.4 MM

I hope this helps someone.

[Frank Reiner]

Originally Posted by lakesurfer

Pinion Bearing Shims: An Alternative plus OEM Part Numbers

My project required me to replace the flange yoke on my differential, plus I upgraded to a Quaife ATB differential unit. These required adjusting my pinion depth to regain a good contact pattern between the pinion and crown gears.

Re: Highlighted statements

How did replacing the yoke and the diff result in a change of pinion depth?
The center of the ring gear (crown wheel) did not move depth-wise with respect to the pinion, and changing the yoke did not change the pinion shim.