A dual mass flywheel is a rotating mechanical device containing moving components.
It consists of two flywheels (the primary and secondary flywheels) that rotate independently of each other. One is attached to the clutch assembly and the other to the crankshaft of the engine.
Between the two flywheels are bearings and a series of springs, which dampen the engine vibrations and prevent most of them from reaching the gearbox.
Valeo does not recommend the resurfacing of dual mass flywheels!
Why does a Dual Mass Flywheel not be reconditioned?
Contamination of the Dual Mass Flywheel
The shards of steel alloy being removed during the skimming/machining process may contaminate the internal components of the dual mass flywheel (metallic dust).
Flywheel Bearing Damage
Due to the movement in the secondary flywheel it can be difficult to clamp it correctly.
Shocks from impacts to the flywheel can damage the bearings.
Incorrectly Machined Surface
- Risk of inclined machining to the friction surface/incorrect runout.
- Risk of excessive reduction of the thickness of the secondary flywheel.
Resurfacing Flywheel Bolting/Mounting Surface
If only the friction surface is machined, the dual mass flywheel will have an increased step (working height of the pressure plate), thus increasing the bearing load because of the "artificial" wear.
Flywheel bolting/mounting surfaces with dowel pins can not be machined. Removing the dowel pins may damage the unit.
Flywheel manufacturers are now printing warnings in dual mass flywheels to advise that they not be reconditioned.
As the risk of reconditioning a dual mass flywheel is high, parts manufacturers will not honor warranty claims where reconditioning is evident.