Car Mechanics

Car Mechanics July 2018

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Car Mechanics is the UK's only car magazine with essential advice on maintaining and repairing popular makes and models. It’s an invaluable motoring resource that appeals to both the DIY car enthusiast and the more experienced motor trade professional. Car Mechanics has helped save money for our readers every month since 1958. Each issue includes a wide range of in-depth features written in a clear, straightforward manner: • Readers’ motoring-related problems answered for FREE • Real-life motoring dilemmas from our man in the garage trade • Electronic diagnostics delves inside a different modern vehicle each month to explain its management system • Survival Guide looks at new and used component prices for a particular vehicle • Used Car Focus is an in-depth buying guide on a specific make and model • Service Bay covers a full service with close-up images and comprehensive descriptions • Project cars are a major part of the structure of the magazine as we buy, fix and sell different vehicles over a period of months So if you're into saving money and being a home technician, Car Mechanics will help you out - guaranteed!

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United Kingdom
Kelsey Publishing Group
4,16 €(Inkl. MwSt.)

in dieser ausgabe

3 Min.
motorway skills

From June 4, learner drivers in England, Scotland and Wales will be allowed to take driving lessons on motorways, as long as they are accompanied by an approved driving instructor in a vehicle fitted with dual controls. It’s not a compulsory requirement and the driving instructor will have to decide if the learner is competent enough to consider driving on a motorway. For me, this is a good idea and it has been a long time coming. In the past, you could be a learner one day, pass the driving test the next and get straight onto dual-laned fast roads without ever having experienced them. I can’t remember the first time I drove on the motorway system – it hasn’t stuck in my mind. What I do remember, though, was being handed…

14 Min.
transferring the drive

Unlike steam engines or electric motors, the internal combustion engine cannot generate maximum torque from zero crankshaft speed. Some kind of clutch mechanism is required not only to apply power progressively to the transmission, but also disconnect drive promptly, to facilitate gear changes. In 1889, Gottlieb Daimler and Wilhelm Maybach devised the first friction clutch to operate the four-speed gearbox in their Stahlradwagen, which was licensed to be built in France by René Panhard and Émile Levassor. Advances by Levassor in engine layout and direct-drive systems, plus developments in propshafts and differentials by Louis Renault, increased engine power, speed and efficiency, with clutches keeping pace. From a design standpoint, one crucial development was the introduction of the diaphragm spring pressure plate, invented by LuK in the 1960s, which replaced the earlier…

4 Min.
how dmfs work & what goes wrong

Until fairly recently, flywheels were solid, heavy lumps of metal that performed damping duties by employing weight to smooth the torsional vibration that resulted from the crankshaft speed increasing and decreasing on each firing stroke. The need to reduce weight and maintain – or increase – torque levels at lower engine revs has necessitated that the solid flywheel be cut in half and the centre section hollowed out to incorporate a damping mechanism. This means that one half of the flywheel is connected to the engine, the other to the transmission. Supported by a centre bearing (or a bush, depending on application), the two flywheel halves can rotate by more than 180°, although a typical average is around 100°. While a solid, or single mass, flywheel can be ruined, it tends…

1 Min.
sac – the self-adjusting clutch

Developed by LuK and fitted to many models from 1996, the SAC addresses the weightier pedal and inconsistent bite point as the friction plate wears and causes the geometry of the release mechanism to alter. The self-adjusting mechanism is incorporated within the pressure plate, which consists of a sensor spring and adjuster ring that keep the diaphragm spring geometry consistent. During fitting, it is advisable to use a special tool to apply an even load to the centre diaphragm spring ‘fingers’ before the retaining bolts are tightened. A riskier DIY strategy is to not use the tool but to ensure that the bolts are tightened evenly, so that the pressure plate is not pulled in one specific direction. This can cause the self-adjusting mechanism to over-compensate, and Schaeffler recommends that…

1 Min.
making dmfs last longer

Like diesel particulate filters, a worn DMF may be a symptom of other mechanical issues and not the cause, because an engine that is not running evenly will create additional vibrations that the DMF must absorb. Worn/leaking fuel injectors, a clogged EGR valve, low compression, or skipped servicing, for example, may be responsible. A tired battery, or starter motor, can prevent optimum engine cranking speeds that, again, place the DMF under stress. Before replacing the DMF needlessly, look for other underlying problems. Tuning the engine to increase torque will also place the DMF outside its original design parameters and is likely to shorten its life. Pay attention to towing weights, too. Try to maintain a smooth driving style, especially as many modern cars possess such tall gearing. Consider that the DMF…

1 Min.
enhancing clutch life

Regardless of the many detailed improvements made to clutch kits over the years, driving style remains the greatest influencer on clutch life. Using the clutch pedal permanently as a foot rest tends to wear-out the release bearing, as does keeping the clutch depressed for long periods of time. Should you expect a relatively long wait, mechanical sympathy (and the Highway Code) dictate that the handbrake be applied, the gearlever placed in neutral and the clutch pedal released. Excessive clutch slip, especially at high engine speeds, overheats the driven plate’s friction materials, as well as the pressure plate and flywheel surface, which can be identified by ‘bluing’ on the metal; this is why tow-cars tend to be more at risk of premature clutch wear. While clutches tend to be maintenance-free, ensure that any…