Good info. I have never taken a turbo apart. I just thought it had ball bearings from things I have read. I recall some early turbos in the 1980's had problems with oil coking from heat-soak, causing bearing failure. Perhaps they meant journal bearings. Makes sense since the bearings are flushed w/ oil.

Something round, about the size of a ball bearing, was bouncing around in the #1 cyl of my 1985 engine, since there were circular depressions in the piston top, and similar on the pre-chamber outside. Don't know if that caused the failure at 330K miles. Several other cylinders had chunks missing from the pistons around the ring grooves, but not such pocked damage. It did make a bad noise about 6 months prior that, sounding like something bouncing around inside, then went away after a minute idling. When it made it the 2nd time, I drove ~2 miles before the engine stopped and wouldn't turn over.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I didn't think you actually forgot it as you would have had a good sized oil leak if you had.

But, you did say "There are no "rubber" seals internally only a paper type gasket...". O-rings are seals.

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84 300D, 82 Volvo 244Gl Diesel

The bearings on your turbo are what are called free floating bearing. The bearing is not mount solidly anywhere. Their side ways play is arrested by some sort of snap ring.

There is clearance between the Shaft journals and the inside of the bearing and there is also clearance between the inside of the bore of the bearing housing and the outside of the bearing.

There is a seperate thrust bearing that is mounted solidly.

The shaft bearings are circled in the pic.

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84 300D, 82 Volvo 244Gl Diesel

Ahhh, that's why some rebuild kits specifically mention a 360° thrust bearing instead of a 270°!

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RIP:
2011 E350 BlueTEC, Schwartz 81k (totaled by uninsured drunk driver)
1964 Unimog 404.1 (wrongfully towed by the city)
1994 E320, Brilliantsilber 208k (transmission shuffled off after sudden catastrophic fluid loss)
1982 300D, Silberblau under a blue repaint 256k (sold for parts)
1995 E320 Polarweiss, 131k (sold for parts)
1995 E300D Polarweiss, 287k (totaled by drunk driver)

Gerrett T3 and T4 turbos also can have different seals on the Compressor ends.

So you need to be sure you get a kit with Piston/dynamic type Ring seals on the Compressor side of the W123 Turbos.

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84 300D, 82 Volvo 244Gl Diesel