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master cylinders
beaver34 - 3/6/10 at 11:22 PM

can someone explain the sizes of m/c to me,

what the differnce between 0.625 and 0.70

not just 0.075

Madinventions - 4/6/10 at 12:14 AM

It's all about the volume of fluid you are moving. A 0.7" diameter master cylinder will move more fluid for a given travel as opposed to a 0.625" one. So basically, a larger diameter master cylinder will give you shorter brake pedal travel and you'd have to press it harder.

A 0.7" diameter m/c will move 7.8cc of fluid per cm of travel, whereas a 0.625" one would move 6.2cc. You therefore need to match the m/c size to the type of calipers you're using (how much piston area) and your preferred feel of brake pedal.

And then of course there's the brake pedal ratio to consider....

Take a look here for some more info.

HTH,
Ed.

[Edited on 4/6/10 by Madinventions]

beaver34 - 4/6/10 at 07:44 AM

quote:
Originally posted by Madinventions
It's all about the volume of fluid you are moving. A 0.7" diameter master cylinder will move more fluid for a given travel as opposed to a 0.625" one. So basically, a larger diameter master cylinder will give you shorter brake pedal travel and you'd have to press it harder.

A 0.7" diameter m/c will move 7.8cc of fluid per cm of travel, whereas a 0.625" one would move 6.2cc. You therefore need to match the m/c size to the type of calipers you're using (how much piston area) and your preferred feel of brake pedal.

And then of course there's the brake pedal ratio to consider....

Take a look here for some more info.

HTH,
Ed.

[Edited on 4/6/10 by Madinventions]


thanks ed,

its for a hydro handbrake, what size should i go for? so if i go for the biggest and wont have to pull it as hard?

JF - 4/6/10 at 07:51 AM

No if you take the biggest you'll have to pull the hardest, but only a small distance. Take a small one and you'll have to pull the lever further, but with less force.

As mentioned above though, keep into account the lever ratio. And in theory, if you go to small you might not move enough oil to engage the brakes properly.

beaver34 - 4/6/10 at 08:08 AM

quote:
Originally posted by JF
No if you take the biggest you'll have to pull the hardest, but only a small distance. Take a small one and you'll have to pull the lever further, but with less force.

As mentioned above though, keep into account the lever ratio. And in theory, if you go to small you might not move enough oil to engage the brakes properly.

ahh, i see there is alot of lever travel,

what do you think i should use, i run cosworth rear calipers

PuppiesBalls - 4/6/10 at 08:34 AM

is it possible to use a notmal master cylinder for a hydraulic handbreak?