Technical brakes

i installed new front rotors and chevy calipers, new steel brake lines front and back. new MC and booster. it will stop but with excessive force. has vacuum. little advice here . 1957 chevy. new wheel cyl in rear too.

 

The booster needs to have a 3/4" ID line supplying vacuum & then a short rubber hose to the booster's nipple. All else the bore on the master cylinder needs to be 1-1/8".

 

Also what is the pedal ratio? unassisted is normally 6:1, power 4:1.

 

not sure how do i measure that

 

The distance from pedal pad to brake lever pivot, divided by lever pivot to pushrod pin distance. Ex. 8" pedal pad to pivot divided by 1.5" pivot to pushrod pin = 5.33

Also check for binding, pushrod angle where it enter the booster or MC, plugged rubber lines, etc.
I've had old rubber flex lines swell shut

 

57 Chevy with exactly what calipers and rotors? Post part numbers or at least whatever it was that they would have been OEM for. 57 Chevy should have been front drums, so what’s being used to adapt the disk setup to the car?

Same for the master cylinder and booster. What are they? Where did they come from? Installed where on the car?

Rear wheel cylinders are original spec?

How is the pedal assembly? Modified to work with whatever all of this is? Or an aftermarket replacement?

How is it plumbed? New hard lines are good, but what’s the rest of the story? Proportioning valve installed? Residual pressure for the drums? Plumbed correctly?

Is this a kit from somebody? Or are you making it up as you go along?

Has it ever worked correctly? Or is this a new build?

 

ok here i go. calipers or for 70 nova. booster 61 impala. rear cyl factory 57 as is brakes. , rotors i’m not for sure. two piece rotor with hub. has proptioning valve. master cylinder new booster i think is 7/8 bore. ebay. new steel lines from the brake store. prebent. brake hoses in front are new steel braid. pedal is good. has adj rod for booster to mc

 

this is the mc.

 

Ok, so 70 Nova is a basic single piston GM caliper. How is it mounted to the suspension? Is the rotor centered in the caliper? If not, you lose a lot of braking effort forcing the pads to contact the rotor.

1” bore master should be ok, but you’ll need to look at your pedal ratio.