..which size bore master cylinderi really need

[De-noz]

Guys, i have a to hard brake pedal feeling in my 65 Olds 442 with a 1" master and disc/drum
( pushrod bolt to upper hole)

This combination works until i switch from power to manual... always read that with power brakes you need 1 1/8 and with manual 1 "

Sooo it´s seems i´m a exception, question is now...which size?

Must i goo to a 15/16“ master and hope everything will be okay or better go to 7/8“ and be safe ?

thanks from germany

[65 drop top]

It really depends on your calipers piston area and pedal ratio. Which calipers are you using? I'd guess pedal ratio is 6:1? Most likely though a 7/8" is going to be what you need.

[De-noz]

What i know is, the front Disk (10.75") & calipers are from the 67-72 cars...i assume stock size is 2.75" (one piston)


About the piston ratio: really don´t know, never measure it--- I only bolted the rod to upper hole....


Let me know if must measure the ratio.

[andrewb70]

Why not go back to power brakes?

Andrew

[De-noz]

no space for a booster.

think i try a 7/8" bore MC and see what happens, may some one know a low cost 7/8" MC with 1/2"-20 & 9/16 ????

[andrewb70]

I don't remember the port size, but I'm using a 7/8" bore MC from a 1995 Dodge Sprint. It's aluminum and has a plastic reservoir. The bolt pattern is not quite right, but it's easy to elongate the holes. I think I paid $65 for it. Works awesome.

Andrew

[Skip Fix]

Most of the stock F and A body manual disc/drum cars did use a 1".

I think there is also a smaller than 1" aluminum manual S-10 MC.

[TheParker]

I don't remember the port size, but I'm using a 7/8" bore MC from a 1995 Dodge Sprint. It's aluminum and has a plastic reservoir. The bolt pattern is not quite right, but it's easy to elongate the holes. I think I paid $65 for it. Works awesome.

Andrew

What dowel did you use and how do you keep it in place?

[andrewb70]

What dowel did you use and how do you keep it in place?

By "dowel" I assume you are referring to the pushrod? The MC has a deep pocket for the pushrod and I reused the push rod that came with the 79 Malibu MC that I had before that.

Andrew