Clutch Disc: Service and Repair
Checking and/or replacing the clutch and clutch driven plate
Special tools:
999 5112 GEAR SECTOR 999 5112 Gear Sector
999 5662 Compression tool 999 5662 Compression Tool
999 5663 Centering tool 999 5663 Centering Tool
999 5677 Counterhold 999 5677 Counterhold
Note! Removing the transmission: To remove the transmission, refer to the car model and year.
Note! The illustrations show a self-adjusting clutch. Where there are differences, these are noted.
Removal
Blocking the flywheel
Use gear sector 999 5112 GEAR SECTOR 999 5112 Gear Sector.
Applies only to certain engine versions with self adjusting clutches:
Secure the clutch automatic adjustment.
Use counterhold 999 5677 Counterhold 999 5677 Counterhold. Align the counterhold, see below.
Aligning the counterhold for automatic clutch adjustment
Applies only to certain engine versions with self adjusting clutches:
The three pins on the counterhold lock the automatic adjustment.
Position the tool as illustrated.
Ensure that all the three pins (see the illustration) go into the groove in front of the tensioner springs for the automatic adjuster.
Press the ring against the pressure plate. Pull out the counterhold springs. Secure the three hooks in the center holes of the outer edge. See Blocking the flywheel.
Installing the compression tool
Install compression tool 999 5662 Compression tool 999 5662 Compression Tool , together with the conversion kit on the clutch. The tool is modified as described in the Workshop Guide.
Ensure that the hooks grip correctly, although without clamping the adjuster springs.
Center the compression tool and tighten the screw to light contact against the diaphragm spring. At the same time, check that the hooks on the tool are in position.
Applies only to clutches without self adjustment:
Note the position of the handle with slots. Then screw in by not more than two turns .
Remove the clutch and clutch driven plate
Applies only to certain engine versions with self adjusting clutches:
Compress the clutch so that the automatic adjuster is not under load.
If the clutch is worn, turn counterhold automatic adjustment to the original position marking.
The marking consists of two stamped arrows.
Then continue to screw in the compression tool until the diaphragm spring has pressed the pressure plate to a free position.
A click can be heard when the clutch pressure plate snaps out.
Remove the clutch and the clutch driven plate .
Relieving the load from the clutch diaphragm spring
Note! Do not allow the diaphragm spring to be under load for a long period of time. Remove the load as soon as possible. Leave the compression tool in position.
Applies only to certain engine versions with self adjusting clutches:
Note! Keep fingers away from the three clutch rivets when relieving a load or removing the compression tool. There is a risk of clamping injuries.
Checking the clutch
Wipe the clutch with a dry cloth.
Check carefully for over heating damage, cracking, scoring or other damage to the friction surface
Check that spring is not damaged or broken.
Checking the pressure plate for out-of-true
Wipe the pressure plate friction area clean.
Check any out-of-true carefully. Use a ruler and a feeler gauge. Out-of-true is permitted in one direction only.
Out-of-true must not exceed 0.2 mm . If out-of-true is greater, replace the clutch.
The clutch must be replaced as a complete unit.
Checking the clutch driven plate
Wipe off clutch driven plate using a dry cloth. The cloth must be free of oil and contaminants.
Check the clutch carefully for signs of wear, damage through overheating, cracking or other damage.
Note! The clutch driven plate must always be replaced if there are no radial ripples remaining on the friction coating. The clutch driven plate must also be changed if there is oil or grease on it.
Checking that there are no cracks or large scratches on the flywheel
To replace the flywheel, see Flywheel, replacement, M56 Service and Repair.
Installation
Installing the centering tool for the clutch driven plate
Use centering tool 999 5663 Centering tool 999 5663 Centering Tool. The drift is modified as described in the Workshop Guide. The conversion kit is included.
Remove the cone from the centering tool.
Install the centering tool in the flywheel center as far in as possible.
Use a wrench as a counterhold. Tighten the outer socket so that the drift expander locks the centering tool.
Feel to see that the centering tool is secured in the crankshaft.
Installing the clutch driven plate
Caution! Turn the slightly longer part of the clutch driven plate hub in towards the flywheel. There is a marking on the clutch driven plate.
Install the cone on the centering tool. Tighten the cone by hand and secure the clutch driven plate.
Note! Tightening tools must not be used on the cone or damage may be caused to the clutch driven plate.
Installing the tools on the clutch
Install counterhold 999 5677 Counterhold 999 5677 Counterhold. See Aligning the counterhold for automatic clutch adjustment.
Install compression tool 999 5662 Compression tool 999 5662 Compression Tool. See Installing the compression tool.
First tighten the center screw on the compression tool to light contact. Then compress the clutch.
Note! When the center screw comes into contact with the diaphragm spring, the screw should, for a loose clutch, be tightened a maximum of 4-4.5 turns.
Applies only to certain engine versions with self adjusting clutches:
Note! When the center screw comes into contact with the diaphragm spring, the screw should, for a loose clutch, be tightened 4.5 - 5 turns or until a clear click is heard.
Installing the clutch
Applies only to certain engine versions with self adjusting clutches:
Check that the clutch automatic adjustment is secured with counterhold 999 5677 Counterhold 999 5677 Counterhold.
Applies to all clutch versions:
Install the clutch and locate the guide pins.
Check that the clutch is in contact with the flywheel all around its circumference.
Carefully tighten the six screws, crosswise, so that the clutch is guided up onto the guide pins and lies in contact all around with the flywheel.
Tighten the screws crosswise to 25 Nm .
Removing the tools
Screw out the center screw. Remove the compression tool.
Note! Applies only to certain engine versions with self adjusting clutches: Keep fingers away from the three clutch rivets when relieving a load or removing the compression tool. There is a risk of clamping injuries.
Applies to all clutch versions:
Remove the hooks. Remove the counterhold.
Remove the centering cone from the clutch driven plate.
Remove the socket. Tap the centering tool lightly with a rubber mallet so that the expander releases. Use a rubber mallet so that the threads are not damaged. Remove the centering tool.
Remove the flywheel gear sector.
Note! Installing the transmission: To install the transmission, refer to the car model and year.