Technical Answers to your Questions

CORRECT CLUTCH FITTING PROCEEDURES

It is vital to diagnose cause of the old clutch malfunction before replacing with a new or rebuilt unit, to identify the cause of failure.

For example if the old clutch has oil contamination DO NOT  INSTALL A NEW CLUTCH until you have established and cured the cause of the oil leak. Check hydraulic system- Release bearing free travel- Clutch Cable-  plus signs of old Facing Material or oil etc. that may have built up in the Bell Housing which may cause Contamination of the New Clutch. All this must be corrected before beginning installing the New Unit.

Leading Clutch Manufacturers Worldwide such as Borg and Beck - Daikin -Exedy-Sachs Valeo etc. have been publishing articles which are all available by researching the net (i.e. Google) they give clear and accurate instructions on how to diagnose clutch problems and good fitting practices, for specific vehicle applications.

BEFORE BLAMING THE CLUTCH

Clutch Fitting and Installation Tips to assist with resolving Problems and customer complaints.

CORRECT SELECTION AND INSTALLATION OF GOODS OR PRODUCT SUPPLIED IS THE RESPONSIBILITY OF THE OF THE PURCHASER. ALWAYS MAKE SURE THAT THE PARTS YOU HAVE BEEN SUPPLIED  WITH OR HAVE ORDERED, ARE THE CORRECT PARTS. IF IN DOUBT CHECK AS THE PREVIOUS CLUTCH FAILURE MAY HAVE BEEN CAUSED BY INCORRECT PARTS BEING PREVIOUSLY INSTALLED...

Always Ensure the flywheel is resurfaced - Failure to do so will automatically void warranty of parts supplied.

FLYWHEELS MUST BE STONEGROUND & NOT MACHINED IN A LATHE, (If flywheels are not resurfaced, shudder-Slippage or release problems can occur.)

Our computerized clutch testing bench unit gives Clamp Loading - Drive strap release PLUS pedal travel require to release. We frequently test other suppliers units and give written reports. Our Customers can come to our premises and watch their own unit releasing and functioning  correctly. 

DUAL MASS FLYWHEELS

In the case of a Dual Mass Flywheel being fitted to the vehicle (Vehicle manufacturers such as BMW and Porsche recommend they are not machined. If a DMF Flywheel is worn it must be replaced) To check the flywheel.: Axial play between the primary and secondary masses can be up to 2mm. The secondary Flywheel of each DMF also has a TILTING:  clearance of up to 1.6mm for a ball type Bearing and 3.0mm for the plain bearing. Provisional testing can be carried out in the workshop.

If  primary and secondary flywheels can be rotated by more than 20mm in opposite directions by hand (Measured on the Outside Circumference of the Flywheel) the wear limit has been reached and the flywheel MUST BE REPLACED.

THE PRIMARY AND SECONDARY FLYWHEEL MUST NEVER KNOCK AGAINST EACH OTHER. IF IN DOUBT REPLACE THE DMF FLYWHEEL.

Clean gearbox main drive shaft splines and check that the new clutch disc slides freely on the shaft. Grease the shaft LIGHTLY with high melting point Grease. Never use copper based or anti-seize type grease lubricants  they will not adhere and may cause contamination of the friction material resulting in slippage and or clutch shudder. Lack of lubrication of splines/components will lead to clutch drag or failure to disengage gears. Excess Grease may cause slipping/Shudder issues and premature failure of the clutch.

Before fitting the Gearbox :

1. Check clutch release fork for cracks, check clutch cable for signs of stretch, and check the release bearing tube for signs of wear or grooving. IF IN DOUBT REPLACE.
2. Always lightly grease the outside diameter of the tube for smooth sliding of the bearing carrier.
3. Check the bearing on the clutch fork by moving the fork backward and forward to ensure the bearing is secure before refitting the gearbox
4. Dry fit the clutch disc on the spigot shaft- Check clutch disc in Pressure Plate (COVER ASSEMBLY) for clearance - Ensure clutch disc is in the right way and does not foul on flywheel Bolts etc.
5. ALWAYS use an alignment tool to ensure correct alignment and avoid spline damage.  (Burring on splines is a Major cause of difficult clutch disengagement)  Align any flywheel dowels to the cover assembly.

Tighten the bolts in a diagonal pattern NEVER use air-tools to install a clutch Cover Assembly. Torque down bolts in an uneven pattern.  Failure to do this in some cases such as lever style covers could cause the release lever struts to dislodge from the pressure plate casting.

When the pressure plate has been torqued down to the flywheel Ensure the diaphragm tips are in a parallel or slightly upward position. If they are below horizontal it indicates the clutch plate is too thick or the flywheel step/recess is incorrect. RELEASE PROBLEMS WILL OCCUR - DO NOT PROCEED

Refit Gearbox: NEVER hang the gearbox off the clutch disc or use any force to align the input shaft. Be careful you do not bend the disc or clutch release -shudder problems will occur.
HYDRAULIC RELEASERS - NEVER  SQUEEZE  MANUALLY OR PUMP RELEASE BEARING UNTIL THE SYSTEM IS CORRECTLY BLED OR SEAL DAMAGE WILL OCCUR CAUSING RELEASE PROBLEMS.

Check all Bell housing dowels to ensure they are in the correct position and tighten bell housing bolts. Make sure there is no contamination or cable clips, electrical wiring etc between the Gearbox and Bell housing mating surfaces which can cause misalignment.

Perform any clutch adjustments to vehicle manufacturers specification (REMEMBER THAT THIS IS A NEW INSTALLATION) and always reset the clutch Master cylinder pushrod to obtain correct and comfortable release position. Keep in mind that the diaphragm or Lever tip position will have changed with the new installation.

CABLE RELEASE:
ALWAYS CHECK THE CABLE: if you are unable to disengage the new clutch Start by replacing the cable

HYDRAULIC RELEASE:
If it is a Hydraulic clutch start by checking the clutch Master cylinder and slave, ensure the system has been bled completely and there is no air in the system. This is absolutely critical to obtain maximum travel for clutch disengagement.

Release Bearing Clearance: There must always be bearing clearance. If there is no operating clearance the bearing is in constant contact with the diaphram and the bearing itself. This causes excessive diaphram and bearing wear - causes the clutch plate to not be fully engaged and clutch slippage or release problems will occur.

Depending on clutch type:

With a Hydrostatic  Release Bearing system as the clutch disc wears- the release arm moves the piston into the slave cylinder to compensate automatically and through the life of the clutch maintains a light release bearing contact.

Adjustable Pushrod type :
To maintain the correct bearing clearance the cylinder pushrod can be adjusted to maintain the clearances. (As a general Guide adjust the pushrod until there is approx 19-25mm free movement at the clutch pedal.

Road test the vehicle-NEVER ABUSE A NEWLY FITTED CLUTCH.

Allow a minimum 500km break in period and adjust the release bearing free travel, and again at 1500km. Adjust there after every 10,000km for maximum clutch life.

Remember you will not get paid for doing the same job twice!