Wayne McCluskey, technical training manager at ZF Aftermarket, offers fitting advice for the Sachs twin-plate clutch on two of BMW’s Motorsport Division favourites, the M5 and M6.
These guidelines are applicable to the following vehicles equipped with the S85 engine: M5 Saloon (E60 2003-2009), M5 Touring (E61 2005-2010), M6 Coupe (E63 2004-2010) and M6 Convertible (E64 2005-2010).
A replacement Sachs MF2-228 twin plate clutch is supplied pre-assembled, with the intermediate disc and pressure plate balanced relative to one other and marked with an alignment check line. The clutch is fixed in the correct fitting position with transit supports consisting of cable ties and a wire ring. On delivery, check the ties and wire ring are in place and the paint marks on the clutch housing are aligned. If they aren’t, do not fit the clutch but contact your supplier for a replacement (Figure 1-The clutch is supplied with transit supports fitted).
REMOVAL OF CLUTCH FROM THE VEHICLE
The clutch must be removed and refitted using BMW installation and alignment tool 21 2 300, BMW part number 83 30 0 495 136 (Figure 2-The BMW installation and alignment tool is required).
Step 1: Press the installation and alignment tool into the hub of the twin plate clutch until its locking device snaps into place.
Step 2: Identify the alignment marks on the clutch housing and the reference mark on the dual-mass flywheel, noting their relative positions.
When refitting the clutch, the marks on the clutch housing must be offset by 1800 from the mark on the DMF, not aligned with it (Figure 3 – Identify the alignment marks on the clutch and DMF).
Step 3: Loosen each of the clutch housing securing bolts by half a turn, following the sequence shown (Figure 4 – Loosen clutch retaining bolts in sequence). Continue to loosen the bolts in this sequence half a turn at a time until the preload of the diaphragm spring can no longer be felt.
Step 4: Remove the clutch from the DMF and secure it in a bench vice by clamping the base of the installation and alignment tool. If the clutch is to be reused, do not release the locking device on the tool.
FITTING A NEW CLUTCH
Step 5: Place the new clutch on the bench with the driven plate facing upwards and cut off the cable ties, leave the wire ring in place for now.
Step 6: Clamp the BMW tool in a bench vice and pull the knurled pin to release its locking device.
Step 7: Lift the clutch onto the tool and press down until it snaps into place, locking the clutch components.
Step 8: Remove the assembly from the vice and offer up to the DMF, paying attention to the following (Figure 5 – Clutch housing alignment marks must be at 1800 to DMF mark):
1. The alignment marks on the clutch housing must be offset by 1800 from the reference mark on the DMF
2. Each dowel pin must be fully inserted in its corresponding hole on the clutch housing
3. Each coil spring must be fully inserted in its corresponding recess on the DMF.
Step 9: Fit the clutch housing to the DMF with the securing bolts, finger tight at first then tighten in the correct sequence to the torque setting specified by the VM (Figure 4).
Step 10: Remove the transit support wire ring from the diaphragm spring.
Step 11: Remove the installation and alignment tool from the clutch hub by pulling the knurled pin to release the locking device.
REFITTING A USED CLUTCH IN THE VEHICLE
Follow the instructions for fitting a new clutch from step 8 onwards, omitting step 10 as the transit support wire ring will not be present.