RT-40/41 Master Cylinder Sizes?

[Rick Ross]

Can anyone tell me what the most common master cylinder sizes are for a Ralt RT-40/41? My car currently has the following:

Front - 0.70"
Rear - 0.75"

I was surprised to see that they are diffferent diameters -- my Swift DB4 had the same diameter MC's for the front and rear systems.

[Paul LeCain]

That's what they came with when new. We use 13/16" F & R.
It depends on what kind of pedal you want. 13/16" gives a very hard pedal.

[bill gillespie]

Hey Rick,

My 41 had the same .7/.75 as your 40.....as Paul said, I went up a size for a harder pedal, but went back to the oem size for easier modulation.....at least for me.

The stock MC pedal travel might be a little long for a right foot braker, but was not an issue for left foot braking .

BTW, what was the issue with your gearbox adapter ?

Merry xmas,
Bill

[Rick Ross]

Thanks for the info, guys. I'm not sure I like the different front and rear sizes, but since it was OEM perhaps I should give it a try. Or I could replace just one MC and use 0.75" front and rear. I am a right foot braker, and I definitely prefer a hard pedal.

Bill - no problem with the adapter plate. Just thought I might get one for the spare motor.

[Rick Ross]

After giving this some more thought, and discussing this with a few friends today, perhaps I should stick with different sized MC's for the front and rear systems. I did not find this necessary on my DB4, but I am aware that many other cars have similar configurations. I assume that the staggered MC piston sizes allow for a more optimum brake balance bar position? In other words, for equal pushrod input force, the smaller MC on the front will allow for a higher front system pressure, allowing the balance bar pivot to remain closer to the center?

Since I do prefer a very hard brake pedal, perhaps I will go up one size on each sysem, to 3/4" front and 13/16" rear.

[kala]

Rick
Consider trying that MC combo with -2, we like it very much.
Shelton