November 2020

NOVEMBER 2020 AFTERMARKET 35 “Technicians can also access REPXPERT direct from their mobile device, with extra functionality such as a barcode scanner that will take you straight to all of the technical documents for the parts you have ordered.” Equipment “There is not a great deal of specialised equipment required, but a few essentials will make the job easier; a two-post ramp and a working transmission jack – or two if working on larger vehicles preferably with a tilting head for a trouble-free refit. “A universal alignment tool will also make gearbox installation easier and prevent damage to the new clutch. While it is essential to use a special tool to fit self-adjusting clutches, Schaeffler’s SAC tool has added value, as it can be used during any clutch installation to help ensure correct fitment, whilst also including special alignment tools to suit all the latest BMW applications. “A DMF can be checked for wear prior to removal by using a LuK DMF tool in conjunction with the DMF CheckPoint function in the REPXPERT app. If the DMF does need replacing, then the app also informs the technician if new bolts are required and what torque values to use.” The right parts “Once the parts have arrived and the gearbox has been removed,” continued Jeff, “it’s always worth conducting some basic comparisons. “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. “On many LuK clutches ‘Getriebe Seite’ may be seen, which is German for ‘Gearbox Side’, while ‘Schwungrad’ is translated to ‘Flywheel’. If something different is identified – or no direction is given – technicians should carefully check the installation instructions, to avoid problems caused by fitting the drive plate incorrectly. “It is always worth checking the reluctor/sensor 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 – if it has been spotted before fitment. “A modern plastic CSC can obviously look different, especially if the original was metal, but it should have the same number of fixings and the pipe position should be similar. It may sound simple, but technicians should always read the instruction sheet inside the 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. “Worn or seized cross shaft bushes need to be rectified; bent or damaged forks need to be replaced; technicians need to 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.” Finishing touches Jeff concluded: “Technicians should never grease plastic release bearings. On most pull-type clutches, technicians should fit the release bearing to the gearbox, and locate it to the clutch cover after fitting the gearbox. They need to be extremely careful when inserting the gearbox; swinging up and down on the back of a gearbox, to fit it to a poorly aligned clutch, will most probably cause damage and judder.” MEYLE-HD Flex disc New products are continuing to help improve the performance of clutch and transmission systems. Commenting on the MEYLE-HD flex disc Patrick Stüdemann, Technical Trainer International at MEYLE said: “Optimal winding technology reduces inner friction and thus the development of heat inside the flex disc. In addition, the optimised push and pull characteristics minimise wear. The improved thread stability inside the MEYLE-HD flex disc optimises breaking load, while the full- surface, comprehensive yarn packages inside increase torque resistance up to 3,000 Nm. The flex disc also reduces torque peaks and boasts wavelength frequency damping and sound insulation. The rubber blend of the flex disc is heat-resistant up to 130 °C, while OE parts can usually only withstand temperatures up to 90 °C.” Here MEYLE provides a guide on how to remove and install the MEYLE-HD flex disc, using a Mercedes S211 as an example. Removal of the installed flex disc To remove old flex disc, expose cardan shaft. For some vehicles, it may also be necessary to remove the underride guard and/or parts of the exhaust system. For many vehicles, it may make sense to loosen the centre bearing, as this will simplify removal. Once bolts have been loosened, flex disc can be removed. For some cars, it’s important to remember not to place any weight on rubber of vibration absorber when removing flex disc, as this could tear vibration absorber. If any flex disc spacers remain in cardan shaft flange, these need to be removed. Any rust should also be removed. Inspect the cardan shaft During repair, guide bushings of cardan shaft should be inspected and replaced if worn. Sufficiently grease differential pin and cardan shaft bushing before attachment to differential. Centre bearing of cardan shaft should also be inspected for wear during repair. Check rubber mount of centre bearing to ensure it is not torn. If cardan shaft is clearly off-centre in centre bearing, this is an indication of fatigue in centre bearing rubber. Worn rubber often leads to sounds and vibrations. Installation of the MEYLE-HD flex disc Before installation, observe cardan shaft’s rotational direction when driving forwards. Gearbox flange ‘pulls’ the cardan shaft over inner winding of the flex disc. Flex disc should be installed accordingly. Same applies to the rear flex disc. Here, flex disc should be installed in such a way that cardan shaft flange ‘pulls’ the differential flange over the large inner winding of the flex disc. Once nuts and bolts are in place, these can be tightened with the specified torque. Right: BIO system from Dayco

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