Nut and Bolt paint markings

[AudioGuy]

I am looking to find the factory specifications for the meaning of different paint colors on various nuts and bolts.  Some are marked with yellow paint.  Is there any source to reflect the which nuts or bolts are marked with which color?

Mark

[al_lieffring]

I had been told once that the color of the dots was to identify the inspector. Each inspector had a different color. They were Mercedes' equivilant of the "inspector #12" tag found in the pockets of new trousers.

[Benz Dr.]

Not that anyone will believe this but........ the paint dots are made with a special torque wrench that shoots a bit of paint out once it gets to the proper setting. Some inspector guy on the line looks at all the dots and says it's OK and the car moves out the door.

[SteveK]

I believe it.  I'm in the construction business and we use "sqirt washers" today when assembling structural steel.  They squirt out a small amount of paint when they are properly tourqued and then the inspectors can see it was done right

[Douglas]

Mark,

The late Frank Mallory gave this response in a forum when someone raised this exact question:

"Actually, there is a field of study know as "dotology" that is devoted
to analysis, recognition, and cataloging of the paint spots on Mercedes
(no joke).

Most of the paint spots were applied by the special torque wrenches used
by Factory inspectors; when the wrench reached the specified valoe for
that fitting, it squirted out some paint.

Other spots were put on springs, motor mounts, and other components, to
designate their value in shore hardness, etc.

The reason these marks are being studied is that when a car is restored
to 100 point condition, it is considered essential that it have the same
paint spots it left the Factory with.

Frank M."

[280SE Guy]

Found this picture in a European Mercedes Benz 280S/280SE/280SE 3.5/280SEL 3.5 brochure: