Clutch: Service and Repair

Remove Or Replacing Clutch

Note: Transmission is removed!

SAC clutch (self-adjusting clutch): Identifying feature:
^ 3 recesses, each with one pressure piece (1) on the adjustment ring and one compression spring (2).

Note: Illustrations shows new position of pressure pieces.

6-cylinder engines: Block flywheel (1) with special tool 11 2 170.

8-cylinder engines: Block flywheel with special tool 11 2 070.

Release screws and remove SAC clutch from flywheel.

Caution: Do not use a special tool to detach SAC clutch from flywheel.

Remove clutch plate (1) from flywheel.
Clean flywheel, check for wear and damage.
Replace damaged flywheel.
Check deep-groove ball bearing in crankshaft for ease of movement and leaks and if necessary replace ball bearing.

Caution: Always replace contaminated clutch plate, e.g. by oil, cleaning agent.

Check clutch plate for damage and friction rust in hub profile and replace if necessary.

Checking clutch plate for wear: Measure lining protrusion on lining rivets at closing head (A) in each case.

Note:
Rivet connection
a) Closing head
b) Swage head

Replace clutch plate if lining protrusion at closing head (A) is less than 1 mm.
Connect clutch plate to cleaned transmission drive shaft and check that it can move easily.

Caution:
Do not clean SAC clutch with high-pressure cleaner or washing machine as this may impair function of adjustment unit.
Clean friction surface only.
Check SAC clutch for wear and damage and replace if necessary.

Reinstalling removed SAC clutch and clutch plate:

Note: Locking hooks (1) of special tool 21 2 180 must engage in openings in SAC clutch.

Set SAC clutch down on a clean surface. Install special tool 21 2 180 in SAC clutch (1).

Press together special tool 21 2 180 at handles (1) up to stop and hold firmly.
Simultaneously tighten down knurled screws (2).
Adjustment ring of SAC clutch is now secured in its original position (wear position).

Caution: Do not reset adjustment ring to new position.

Note: Insert special tool 21 2 170 only in area of bores for dowel pins.

Fit special tool 21 2 170 and tighten down at knurled screw (1).

Screw in spindle (1) until diaphragm spring (2) is pretensioned up to stop.

Caution:
Handle clutch plate with care, do not touch surfaces of friction linings.
Install clutch plate (1) in correct position.
Pay attention to text "engine end" / "transmission side".

Center clutch plate (1) with special tool 21 2 141 or 21 2142.

Attach SAC clutch (1) to flywheel.
Pay attention to dowel pins (2).
SAC clutch (1) must be secured by means of dowel pins (2).
Insert screws and tighten down.

Screw out spindle (1) until strain is completely removed from diaphragm spring (2).

Release knurled screw (1) and remove special tool 21 2 170 from SAC clutch.

Release knurled screws (2) and remove special tool 21 2 180 from SAC clutch.

Withdraw special tool 21 2 141 or 21 2 142 with aid of accompanying screw (1) from clutch plate.

Installing Removed SAC Clutch With New Clutch Plate:

Caution: Before installing an SAC clutch which has been in service with a new clutch plate: always reset adjustment ring in new position.

Note: Locking hooks (1) of special tool 21 2 180 must engage in openings in SAC clutch.

Set SAC clutch down on a clean surface. Install special tool 21 2 180 in SAC clutch (1).

Note: Insert special tool 21 2 170 only in area of bores for dowel pins.

Fit special tool 21 2 170 and tighten down at knurled screw (1).

Screw in spindle (1) until adjustment ring of SAC clutch (2) can be turned with special tool 21 2 180 at handles (3).

Press together special tool 21 2 180 at handles (3) up to stop and hold firmly.
Simultaneously tighten down knurled screws (2).
Adjustment ring of SAC clutch is now secured in new position.

Center clutch plate (1) with special tool 21 2 141 or 212142.

Attach SAC clutch (1) to flywheel.
Pay attention to dowel pins (2).
SAC clutch (1) must be secured by means of dowel pins (2).
Install retaining screws of SAC clutch and tighten down.

Screw out spindle (1) until strain is completely removed from diaphragm spring (2).

Release knurled screw (1) and remove special tool 21 2 170 from SAC clutch.

Release knurled screws (2) and remove special tool 21 2 180 from SAC clutch.

Withdraw special tool 21 2 141 or 21 2 142 with aid of accompanying screw (1) from clutch plate.

Installing New SAC:

Caution:
Handle clutch plate with care, do not touch surfaces of friction linings.
Install clutch plate (1) in correct position. Pay attention to text "engine end" / "transmission side".

Center clutch plate (1) with special tool 21 2 141 or 21 2142.

Push SAC clutch onto dowel pins (1) located in flywheel and screw down.

Tightening torque, Clutch to flywheel.

All M8 8.8 Thread = 25 Nm.
All M8 10.9 Thread = 34 Nm.

Caution: Locking piece (1) may only be removed when SAC clutch is screwed down!

Carefully unscrew locking piece (1) clockwise or counterclockwise with a hexagon socket screw key (14 A/F) (2).

Note: A slight snapping of the plate spring while unscrewing is possible.

Withdraw special tool 21 2 141 or 21 2 142 with aid of accompanying screw (1) from clutch plate.