User Guide
DMF function tests
The LuK special tool allows you to perform
the following tests on the DMF:
• Measuringthefreeplayangle
• Measuringtherock
These tests, in combination with a visual inspection to
check grease egress, thermal load, clutch condition,
etc., allow for a reliable assessment of the DMF’s opera-
tional condition.
The freeplay angle is the angle at which primary and
secondary mass can be rotated against each other until
load is exerted on the arc springs. The measuring points
are both end stops in the le-hand and right-hand direc-
tion of rotation. The measured freeplay serves as a wear
indicator.
Caution:
Some DMFs have a friction control disc that can be
felt as a hard stop in one direction. In this case apply
greater force to rotate the secondary mass a few
more millimetres until spring resistance can be felt,
and then allow it to return. This also rotates the fric-
tion control disc in the DMF.
The term “rock” describes the clearance between the
two DMF masses which allows them to be tilted towards
and away from each other.
Caution:
Please note especially Chapter 5.1 “General advice”.
7 DMF function tests