I have renewed my clutch master cilinder. (in fact, carjoy did it) After the job was done, the clutch pedal needed much more force. So i suspected the bore of the cilinder. The bigger the bore, more power is needed to apply the clutch pedal. It turned out that a mastercilinder of a 2.2 was fitted. (my murena was a 1.6)
Then the cilinder is replaced by a smaller cilinder. The clutch pedal become much lighter, but stil not as light as it was.
My old master cilinder have a bore of 19mm, and the first new cilinder had 22mm. The second new cilinder seems to have the same numbers written on it as the old one, alltough the old numbers are difficult to read.
So my gues is that i have now 20,5mm?
Carjoy don't seems to have 19mm cilinders.
Are there rebuild kits available?
The 1.6 clutch master cylinder should be 19mm bore and the 2.2 should have a 20.6 mm bore (note these are really imperial sizes 19mm = 3'4" and 20.6mm = 13/16") but I have found 2.2 master cylinders on a 1.6 before now, and it seems some people don't realise they should be different!
If you had a master cylinder with a 22mm bore as stated then it was entirely wrong! Trying to move that much fluid would make the slave cylinder bottom much quicker and could account for the high pedal load.
If you put a 2.2 master cylinder on a 1.6 then the volume of fluid moved for the same pedal movement will be greater and try to force the slave cylinder further.
If the clutch is almost worn out it usually gets harder on the pedal, so increased pedal pressure can signify the clutch is near the end of its life.
The number cast onto the master cylinder will often be the same as they used the same casting and simply drilled them different sizes.
Simon stock 1.6 and 2.2 seal kits. See their new Murena parts pages.
Roy