Clutch master cylinder bore size

[dal2.0litrefrogeye]

Hi as the title says really off the top of head anyone know the bore of the clutch cylinder ? And anyone know the formular ...is it a smaller bore moves more fluid with a harder pedal feel and bigger bore less fluid with softer feel ???? Regards Confused of Orpington

[Hugo]

Hi as the title says really off the top of head anyone know the bore of the clutch cylinder ? And anyone know the formular ...is it a smaller bore moves more fluid with a harder pedal feel and bigger bore less fluid with softer feel ???? Regards Confused of Orpington

You mean the slave cylinder I presume? In which case you are almost correct - a smaller bore slave will give greater travel at the release bearing for the same pedal travel, but the pedal will feel heavier, and vice versa. The amount of fluid moved depends on the master cylinder. BUT! The effect is not linear; it is the square of the alteration. In other words, if you go from a 1" slave (I'm sorry I don't know what the actual size should be!) to a 1.25" slave, the difference will not be 4:5, but 4 squared to 5 squared, i.e. 16:25. In other words, a small alteration will have a big effect. Increasing the slave by 1/8" will reduce the release bearing by about a quarter. Similarly, if you fit a smaller bore master cyl you will have less travel at the release bearing but a nice light pedal, which of course is not much use if your clutch won't disengage!

[dal2.0litrefrogeye]

hi thanks for reply but it was the master cylinder , my fault should of stated that , any way another member comfirmed what I thought it was , thanks Simon , and I now have clutch pedal with full disengagment
wooohoo