Mercedes Coupes/Sedans/Wagons 1974-1984 Repair Guide

Driven Disc and Pressure Plate

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INSPECTION



See Figure 1 and 2

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Fig. Fig. 1: A fully seated measuring gauge indicates that the clutch plate has reached its wear limit



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Fig. Fig. 2: A partially seated measuring gauge indicates that the clutch plate has not yet reached its wear limit

A spring plate clutch that automatically compensates for wear is used, so no periodic adjustments are required. Apart from the usual slippage which accompanies severe wear of the clutch plate or disc, Mercedes-Benz has a simple tool, which can be purchased from a dealer that measures the amount of wear on the clutch plate. Actually, it is a simple "go-no go" gauge.

  1. A plastic shim is installed between the slave cylinder and the bellhousing.
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  3. The shim is provided with two flat grooves running diagonally from bottom to center. When the shim is installed, these grooves appear as slots. Use groove (a) for left-hand drive vehicles and groove (b) for right-hand drive vehicles.
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  5. The clutch slave cylinder pushrod has two different diameters. The jaw width of the test device corresponds to the smaller diameter of the pushrod. If the notches on the test device disappear when the test device is inserted as far as it will go, the clutch plate is still operational.
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  7. If, however, the notches on the test device remain visible, this is an indication that the clutch plate is worn severely and should be replaced.
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REMOVAL & INSTALLATION




WARNING
The clutch driven disc may contain asbestos, which has been determined to be a cancer causing agent. Never clean clutch surfaces with compressed air! Avoid inhaling any dust from any clutch surface! When cleaning clutch surfaces, use a commercially available brake cleaning fluid.

See Figures 3 through 20



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Fig. Fig. 3: Exploded view of a typical clutch assembly's components



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Fig. Fig. 4: View of the clutch and pressure plate assembly



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Fig. Fig. 5: Loosen and remove the clutch and pressure plate bolts evenly, a little at a time ...



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Fig. Fig. 6: ... then carefully remove the clutch and pressure plate assembly from the flywheel



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Fig. Fig. 7: Check across the flywheel surface, it should be flat



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Fig. Fig. 8: If necessary, lock the flywheel in place and remove the retaining bolts ...



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Fig. Fig. 9: ... then remove the flywheel from the crankshaft in order replace it or have it machined



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Fig. Fig. 10: Upon installation, it is usually a good idea to apply a thread-locking compound to the flywheel bolts



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Fig. Fig. 11: Check the pressure plate for excessive wear



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Fig. Fig. 12: Be sure that the flywheel surface is clean, before installing the clutch



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Fig. Fig. 13: Typical clutch alignment tool, note how the splines match the transmission's input shaft



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Fig. Fig. 14: Install a clutch alignment arbor, to align the clutch assembly during installation



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Fig. Fig. 15: Clutch plate installed with the arbor in place



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Fig. Fig. 16: Clutch plate and pressure plate installed with the alignment arbor in place



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Fig. Fig. 17: Pressure plate-to-flywheel bolt holes should align



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Fig. Fig. 18: You may want to use a thread locking compound on the clutch assembly bolts



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Fig. Fig. 19: Install the clutch assembly bolts and tighten in steps, using an X pattern



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Fig. Fig. 20: Be sure to use a torque wrench to tighten all bolts

  1. To remove the clutch, first remove the transmission and bellhousing.
  2.  
  3. Loosen the clutch pressure plate hold-down bolts evenly, 1-1 1 /2 turns at a time, until tension is relieved. Never remove one bolt at a time, as damage to the pressure plate is possible.
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  5. Examine the flywheel surface for blue heat marks, scoring, or cracks. If the flywheel is to be machined, always machine both sides.
  6.  

To install:
  1. Coat the splines with high temperature grease and place the clutch disc against the flywheel, centering it with a clutch pilot shaft. A wooden shaft, available at automotive jobbers, is satisfactory, but an old transmission mainshaft works best.
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  3. Tighten the pressure plate hold-down bolts evenly 1-1 1 /2 turns at a time until tight, then remove the pilot shaft.
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Most clutch plates have the flywheel side marked as such (Kupplungsseite). Do not assume that the pressure springs always face the transmission.

 
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