Why a Clutch and Flywheel Are Often Replaced Together

The labour is the same either way

To get at a clutch, the gearbox has to be separated from the engine. On many cars that is a big job, involving driveshafts, linkages, mountings and sometimes a subframe. The flywheel is bolted to the end of the crankshaft, in plain view as soon as the clutch comes off.

Because the hard work is getting there, adding a flywheel replacement does not double the labour. Doing it later, as a separate job, means paying again for that same strip down. That is the heart of the argument for replacing both together when the flywheel is worn.

Cost obviously matters, and we understand that people want to avoid unnecessary parts. The honest approach is to inspect the flywheel properly rather than replace it by default, and to tell you what the condition is.

Dual-mass flywheels

Many modern diesels and some petrol cars have a dual-mass flywheel. It is made in two parts joined by springs and dampers, which smooth out engine vibration. A solid, single-mass flywheel is simpler and can sometimes be skimmed flat. A dual-mass unit contains moving parts that wear, and it generally cannot be refaced in the same way.

Signs of a tired dual-mass flywheel include rattling at idle that stops when you press the clutch, shudder or vibration when pulling away, and a clunk when you let the clutch up or shut the engine off. On inspection, excessive play between the two halves, heat marks or leaking grease are all reasons to replace it.

• Rattle at tickover that eases when the clutch pedal is pressed
• Judder or harshness on pulling away
• Clunk when lifting off or stopping the engine
• Visible heat cracks, blue marks or grease leaks on inspection

What gets inspected on the flywheel

With the clutch off, the friction face of the flywheel is checked for scoring, hot spots, cracks and warping. A single-mass flywheel in decent condition may be resurfaced, depending on how much metal can safely be taken off. The starter ring gear teeth are looked at too, since damaged teeth cause starter noise.

Whether to replace it is a judgement based on what we find, not a rule. We will not promise either result before the inspection, and we would tell you if the flywheel looked fine and could be reused.

Release bearing, slave cylinder and seals

A few other parts earn their place on the list while access is good. The release bearing, sometimes called the thrust bearing, presses on the clutch every time you push the pedal, and it is very cheap to renew when everything is already apart. On cars with a concentric slave cylinder, which sits inside the bell housing, the hydraulic part is not reachable without the same strip down, so it is often replaced as well.

The engine rear main oil seal and the gearbox input shaft seal are also worth looking at. A seal that is weeping onto the new clutch will ruin it, so it makes sense to renew anything leaking while it is exposed.

Avoiding doing the job twice

The aim is simple: do not close the car up and then discover a worn part that could have been fixed in the same sitting. At Banks of the Tyne we cover clutch replacement and flywheel replacement, and we explain which parts we recommend and why, so you can decide.

Cost depends on the vehicle, the type of flywheel and which extras are needed, so we would quote after looking at the car. If funds are tight, tell us. Sometimes the answer is to fit what the inspection says is necessary, and ask us to note anything borderline.

Frequently asked questions