603.961 connecting rod bearing specs

[sixto]

Looking at section 03-320 in the shop manual, there's an axial play spec but no radial play spec. There are both specs for the crank. Do the same radial specs for the crank apply to the connecting rods? Can someone with a W124 shop manual check if specs are available?

Also I can't figure out how to check con rod axial play. The crank doesn't have a machined surface beside the big end. Something I missed in the manual? Any ideas?

Thanks,
Sixto
93 300SD

[gsxr]

Sixto,

It's mostly Greek to me, but in the printed manual, 03-320 has a section with bearing play in mm that appears to show both specs. I see:

Radial: 0.030 - 0.055 new, wear limit 0.08
Axial: 0.12 - 0.26 new, wear limit 0.50

The manual indicates that axial play is controlled by two thrust washers that locate the crank in the block. What manual are you looking at?

[sixto]

Are you quoting radial play for crank bearings or con rod bearings? W126 03-320 doesn't have specific info for con rod radial play that I can see. At best MB meant to put the same info for crank and con rod but printed the numbers in the crank column.

I can figure how to measure crank axial play at the thrust washers.

The manual has a spec for con rod axial play, presumably at the crank end, but there are no surfaces that will take a feeler gauge. Seems like you'd have to set up a dial gauge which is a bear to do 6 times. The manual doesn't say how to measure con rod axial play.

Thanks,
Sixto
93 300SD

[gsxr]

W126 03-320 has two columns with different data, one says for the crank, the other says for the rods. I didn't try to compare to the W124 (WIS-based) specs. You might want to contact Mark DeGroff and see what he says... this is waaaaay out of my realm of expertise.