4 replies to this topic

[Jordie]

Do they come in different sizes?

Ive seen one on ebay, which says its taller and therefore rare.

Heres a brake cylinder i have next to a clutch one, you can see its taller, so is it rare or just normal?



Jordie

[rally515]

mines like that

[carbon]

Taller master brake cylinders were used on the Cooper S and all of the Austin/Morris 1100-1300 range. Extra fluid capacity to allow for brake pads wearing and fluid level dropping.

Brake master cylinders also come with different bore sizes, typically 0.70 or 0.75 inch. Larger bore gives less pedal travel but slightly heavier pressure needed on pedal.

[tiger99]

Correct, and it is also very important that you have sufficient displaced volume to always apply the brakes fully, allowing for wear and inperfect adjustment, and in the case of dual-circuit brakes, total failure of one circuit, so don't go changing it to a smaller diameter to get a lighter pedal, or you may end up killing yourself when you run out of pedal travel. Each diameter of master cylinder belongs to specific wheel cylinders and calipers.

The reservoir volume is actually far less important than the displaced volume of the cylinder.

Check the Somerford Mini web site for what parts can go together on which cars.

[Big_Adam]

If I may hijack a little, does it matter if you use a tall brake master for a clutch master.

Just I have 2 on the shelf, not sure what each is and I'm too skint to buy another clutch master if I can get away with using an old brake master.