Clutch best practice

MALCOLM SHORT, SCHAEFFLER’S TECHNICAL SERVICES MANAGER, OUTLINES CLUTCH BEST PRACTICE TO PREVENT PROBLEMS AND PROMOTE PROFIT

Some workshops are still avoiding clutch work, preferring instead to send it to a ‘specialist’ that, in reality, has simply learnt the tricks needed to avoid having a car stuck on the ramp overnight when what should have been a five-hour job, goes wrong. By following a few simple precautions, all garages can avoid the pain and problems and potentially start turning a profit from clutch.

Supplying car parts is becoming increasingly difficult, especially when looking at genuine parts from OE suppliers. With millions of errors on the DVLA system, a vehicle registration look-up may not be as accurate as you would think, so furnishing yourself with some basic vehicle details (preferably directly from the car if you have it) will help the motor factor supply the correct part first time.

Good-to-know problem solving information includes finding the correct VAG engine code; knowing where reverse is located on Vauxhall applications to identify the correct CSC; and knowing if a VW has start/stop is essential in identifying the right DMF.

While you are waiting for the parts and/or the car to arrive, it’s a good time to see if any accurate fitting instructions are available, especially if you are not familiar with the vehicle. Schaeffler’s REPXPERT workshop portal is a perfect place to start, as clutch fitting instructions are free or charge for members to access, and can be saved, printed and attached to the job card.

Whilst you are looking up the TecRMI vehicle manufacturer instructions using TecDoc in REPXPERT, you will pass the clutch application listings, so take a quick look to see how many components are shown and check if you have ordered all of the parts required.

If your technicians do not have access to an iPhone or Android phone (or mobile device) installed with the free ‘DMF Checkpoint’ app, then you can also find and print the critical tolerance values from REPXPERT, so they can accurately diagnose DMF wear when the gearbox is removed.

There is not a great deal of specialised equipment required, but a few essentials can make the job easier; a two-post ramp and a working transmission jack (or two if you work on some larger vehicles such as the L200), preferably with a tilting head for a trauma free gearbox refit.

A universal alignment tool will also help with smooth gearbox installation and prevent any damage to the new clutch.

Whilst it is essential to use a special tool to fit a self-adjusting clutch, Schaeffler’s LuK SAC tool has added value in that it can be used during any clutch installation to help prevent judder, and it also includes lots of special alignment tools to suit the latest BMW applications.

Dual mass flywheels can be checked for wear prior to gearbox removal by using a LuK DMF tool in conjunction with the DMF CheckPoint app. If the DMF does need replacing then the app also tells you if new bolts are required and what torque values to use.

When the parts have arrived and you have removed the gearbox, it’s always worth doing some basic comparisons:

Spline count – sliding the drive plate back and forth to distribute a small amount of grease is a good check that the splines are correct (not forgetting to wipe off any excess grease afterwards).

Drive plate orientation – “Getriebe Seite” is German for “Gearbox Side”, “Schwungrad” is “Flywheel”, and if you see something else or even nothing, contact the free REPXPERT technical hotline – the problems caused by fitting a drive plate the wrong way round are easily avoidable!

Dual Mass Flywheels (DMF) – It is always worth checking the reluctor ring on the back of a DMF, even if it’s from a different manufacturer it should still have the same number of teeth and they should be undamaged. OE suppliers such as Schaeffler will replace transit damaged goods as long as it has been spotted before fitment.

Concentric Slave Cylinders (CSC) – A modern plastic CSC can obviously look different, but it should have the same number of fixings and the pipe position should be similar. It may sound simple, but always read the instruction sheet inside a CSC box! It may contain critical information, such as how to find and discard a redundant pipe seal (on Vauxhall applications), and some Ford instructions explain that the O-ring should be replaced by sealant (and not too much!). Check the rest – Worn or seized cross shaft bushes need to be rectified; bent or damaged forks need to be replaced; always replace the ball pivot on BMW applications and check the others; repair leaking gearbox seals and, finally, reset or replace all self-adjusting cables.

Never grease plastic release bearings. On most pull type clutches you fit the release bearing to the gearbox and locate it to the clutch cover after fitting the gearbox. Be careful when inserting the gearbox, swinging up and down on the back of a gearbox to fit it to a poorly aligned clutch will probably cause judder and damage.