Check the friction linings for reuse by measuring from the surface of the lining to the top of the rivet head using a depth gauge (figure 161). If the size is less than 0.30 mm, the disc must be replaced. The disk is also changed if the size approaches this value.
Figure 161. Measuring the thickness of the clutch disc lining to the rivet head
To check the driven disk for runout, it is clamped on a suitable mandrel or clutch shaft between lathe centers and a dial indicator is fixed on a suitable stand next to the disk so that the measuring pin is against the edge of the disk (with a diameter of 175 mm). Rotate the disk slowly and read the indicator readings (figure 162). If the reading is greater than 0.1 mm, you can, if desired, carefully align the disc using pliers. Otherwise, the disk needs to be replaced. Check the sliding of the driven disk sleeve on the splined connection of the clutch shaft. To do this, you need to put the disk on and take it between your thumb and index finger. Move the disc back and forth in the direction of rotation. If the gap is greater than 0.4 mm, there is wear in the splined connection, which is usually located in the disc. Check the inner edges of the disc springs for wear. If deep wear areas are detected, the entire clutch must be replaced.
Figure 162. Checking the driven disk for runout between lathe centers
The tops of all disc springs must not exceed 0.5 mm at the same height. The bent tops need to be straightened again. A special tool is usually used for this (figure 163), however, you can use a steel strip with a slot and bend the edges.
Figure 163. Extension of the disc spring fingers
Lubricate the moving parts of the clutch lever and release sleeve.