89 knowing when your clutch needs replacing
knowing when your clutch needs replacing
By Jamie Rogers on 2018-11-08 12:15:02
Your clutch is the drive-link between your engine and gearbox, and depending on what type of car you drive and the power it makes, and to an extent, your driving style, it could last for many thousands of miles, or be done within a year.
Replacing clutches can be expensive by their very nature, they are inaccessible and difficult to get to, meaning that a replacement takes a good number of hours of labour, and depending on where you are in the country, that could start at around £35 per hour, and easily go further North of £100 per hour.
Usually (but not always), a clutch will give signs of an impending failure long before it actually fails, although in some circumstances, it could just fail. This really does depend on the type of clutch, and the type of failure a loss of hydraulic fluid, for example, could lead to an instant failure, albeit not the actual clutch assembly.
A clutch failure usually happens due to wear the clutch friction plate material literally wears out, this could mean a number of things difficulty to engage gears, loss of drive, a constant slipping (where the engine is trying to drive the wheels, but can´t) or a pedal without pressure.
It´s worth noting that in extreme cases, a failed clutch could also lead to a premature failure of the clutch release bearing, which may or may not include the hydraulic slave cylinder.
Signs of Failure
In most cases, you’ll notice clutch slip not usually from a standstill or in the lower gears, it´s more likely to occur when you´ve engaged 4th, 5th or top gear (depending on how many gears you have). It´s easily recognized as you load the engine (pushing the accelerator pedal), the engine revs will rise sharply, but the speed of the vehicle won´t increase, or certainly not at the speed of the revs.
Cars fitted with turbochargers are more susceptible to this when they hit peak boost pressure is when the engine load is at its maximum; drivetrain load is maxed out.
Other signs of failure could be a complete loss of pressure in the clutch pedal, this could mean a number of things: there has been a fluid loss, either from the master or slave cylinder, the rubber seals in the cylinders have failed, the clutch release bearing has collapsed, or if it´s an older car, the clutch cable has broken.
In all honesty, there isn´t much you can do to stop a clutch from wearing out, or at least not maintenance-wise, although certain driving techniques could help prolong the life. As for the fluid, this should be changed as part of the routine maintenance schedule, or at least every two years if you don´t do many miles.
The reason for this is simple clutch fluid is ’«hygroscopic´, which means it has a tendency to absorb moisture from the air, and water doesn´t have the same characteristics as clutch fluid it won´t be able to operate the clutch.
Driving style can play a part in how long your clutch lasts traffic light Grand Prix´s (racing from red to red) will shorten the life immensely, as will showing off in a cloud of tyre smoke. Thanks to materials engineering and science, modern clutches can take more abuse than those from a decade ago, but they´re still susceptible to being abused.
It´s also worth remembering that some modern cars now have to have the flywheel replaced at the same time as the clutch the days of simply changing the friction plate are beginning to be left behind, you could now be looking at a bill for a clutch plate, diaphragm, slave cylinder, release bearing and flywheel! That´s going to be expensive.
We´ve even heard that a number of Honda owners had to pay for a new bellhousing after Honda redesigned a clutch due to a manufacturing fault that wasn´t covered under warranty.
Whatever car you drive, taking care of the clutch is just good sense it´s one the least replaceable and most expensive components in the car, at least in the terms of a ’«wear part´. If you´re looking to buy a second-hand car, you should always consider the mileage and check to see if it´s had a clutch replacement in the past you could be lumbered with a rather significant bill if you´re not careful.
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