Triumph Stag Clutch Housing/Operation
Clutch drag is the result of insufficient pressure plate lift to completely free the drive plate when the clutch pedal is operated. Contributory factors are; insufficient travel of the slave cylinder push rod, oil contamination, excessive 'run out' of the driven plate facings (buckled), or, in certain circumstances, excessive length of the clutch mounting bolts.
Also, rough operation and/or misalignment of the release bearing can subject the clutch to high frequency vibration and rapid wear of the internal parts making the clutch inoperative.
To establish if the fault is hydraulic or mechanical, the movement of the slave cylinder pushrod must be checked, it must be at least 16mm. if this measurement is achieved then the cause is likely to be mechanical lost movement, therefore, after gearbox removal the following points should be checked.
Examine the gearbox mounting holes for wear or ovality which may allow the gearbox to drop from its original mounted position casing mis-alignment of the release bearing.
The clutch release bearing carrier must be a snug fit on the front cover nose with no tight spots or excessive play. The carrier groove should be unworn, particularly on the front face where it is contacted by the clutch fork trunnions.
The clutch fork must be held securely to the withdrawal shaft by the locking bolt, no play whatsoever is permissible at this point. The release fork trunnions shouldbe round & unworn.
Carfully examine the cross shaft bearings for wear or lack of lubrication, particularly on the withdrawal arm side.
Check the release bearing, which must revolve smoothly while being turned under firm pressure between the hands
Examine the pilot bearing carefully, looking for wear or 'bellmouthing', however slight
Should any components be found to be unserviceable, they must be replaced
Before re-assembly ensure that the clutch plate moves freely on the splined shaft, at the same time revolve the plate to check for excessive 'run out' of the facings. Lightly smear the front nose and clutch fork trunnions with copper grease.
Where a Borg & Beck clutch is fitted as a service replacement for a Laycock assembly, due tomthe difference in mounting flange thickness of the two types, the mounting bolts must be shortened to a length not exceeding 19mm under the head, otherwise the bolts may bottom in the holes and leave the Borg & Beck clutch loose on the flywheel.