S 320 LWB (140.033) L6-3.2L (104.994) (1995)
of the journal.
Hardening
Always harden journals with hardened radii (arrows) inductively.
If this is not possible, scrap crankshaft.
Inspecting Hardening
The setting of the hardening system should be checked by taking metallographic sections in order to achieve proper hardening.
These sections can be taken from test hardenings on scrapped crankshafts.
Check hardening by etching the surface of the journal with a 2% alcoholic nitric acid (HNO3).
No dark patches should appear on the surface of the journal.
The hardened radii must be just as bright as the surface of the journal.
The non-hardened radii darken in color.
As a comparison, it is recommended to perform etching on a journal which has been metallographically checked.
Following this, carefully wash off the nitric acid with alcohol.
Corrosion Protection
Crankshafts which are not re-installed immediately, must be oiled with a corrosion protraction oil.
Examining, Grinding And Hardening Flow Charts
Proceed in the order stated in the diagram when examining and servicing crankshafts.
Section A