Master Cylinder Sizing

[dak697]

OK Guys I need some help sizing a master cylinder for my car
Big tire in the back, drag lites in the front

Brakes
Front
Wilwood 4 pistons Calipers - 1.75" pistons
Rear
GM Metric single piston Claipers - 2.5" pistons
Manual Brakes

Current set up
4 wheel drum brakes. 6 cyl chevy II in the front...Big Ford in the back
Car stops good but they do tend to fade away and require adjustment some weekends...
2850 lbs
135 mph
I have more motor for the car and do not want any problems going a 150 plus

So I need to know what bore to buy. Thanks Dean

[robinhorn]

Good luck making that combo work. I had the GM stuff and wilwood and it does not work together. It's been 7 months and still no luck using anything other then all wilwood.

Buy the wilwood for the front and back and the 7/8 or 1 inch bore Wilwood.

[Tod74]

Good luck making that combo work. I had the GM stuff and wilwood and it does not work together. It's been 7 months and still no luck using anything other then all wilwood.

Buy the wilwood for the front and back and the 7/8 or 1 inch bore Wilwood.

What about wilwood discs on the front with factory drums on the back? I am installing mine right now.... :? It is a drag car only...will it work?

[john858]

got that setup on 70 nova stops fine ,uses a gm master but i would use a wilwood or strange master 3/4 or 1"

[robinhorn]

Wilwood disk on the front and drum on the back is fine. It's when you try and mix two diff calipers. One is solid mounted and one slides.

master will not work from my findings. It seems the fluid to move the sliding calipers vs the solid mounted creates a volume issue.

I have 3 masters, 2 p-valves and 2 sets of rear brakes. One set the gm small caliper and now the wilwood.

Wilwood has had to replace a brand new master for me. Itwas broke right out of the box.

I have replaced brake lines and so on. If anyone can make this work please let me in on the process.

[john858]

i've put aerospace on several cars, liked it well enough that i put it on my own car rolls easy & stops great

[dak697]

what master cyl. have you used? wilwood or fact GM style

[john858]

i use astrange master,don,t need a poportioning valve with it

[dak697]

I was at the track this weekend and looked at SG roadster... Willwoods up front and Metrics in the back...I talked to the guy and he says the thing stops great.. Uses a factory GM Mastercylinder an aluminum one. Has a portioning valve for biased and has residual valves in line.. The only thing that he has to do every day is gets in the car and pumps the brakes up. He said the petal is soft if it sits overnight or for a couple of days. he is not sure why.Said that when they first put the brake set up in they blead the brakes trying to get rid of the soft pedal after sitting and it would not clear up. Once he "cycles" the brakes the brakes have lots of pedal and work fine all day. He is going to see if they have a make and model on the master cylinder.

[john858]

just get a stock nova or camaro master

[dak697]

What year, and a manual or power 1

[john858]

68 to 72 nova none power. what year is your car? if it is 67 or down i would use a strange master it's about $100.00

[dak697]

63 Chevy II ...tube chassic car ..I have lots of room

thanks

Dean

[robinhorn]

I was at the track this weekend and looked at SG roadster... Willwoods up front and Metrics in the back...I talked to the guy and he says the thing stops great.. Uses a factory GM Mastercylinder an aluminum one. Has a portioning valve for biased and has residual valves in line.. The only thing that he has to do every day is gets in the car and pumps the brakes up. He said the petal is soft if it sits overnight or for a couple of days. he is not sure why.Said that when they first put the brake set up in they blead the brakes trying to get rid of the soft pedal after sitting and it would not clear up. Once he "cycles" the brakes the brakes have lots of pedal and work fine all day. He is going to see if they have a make and model on the master cylinder.

This is the problem I am having with the stock in the front and the wilwood in the rear. If that guy thinks that is how brakes work and he is ok with that then that's cool with me But I refuse to put myself in a car that the brake pedal does not work first or second pump.

I drive my car on the road and the last thinkg you want is a soft or pedal you have to pump. Return roads come up real fast on some race tracks I have been to.

[john858]

is your master on the firewall or floor?

[dak697]

My master cylinder is on the Firewall..

I was thinking of going to a 1.125" MC Disc/Disc configuration

Strange or a OEM style 1

[dak697]

I talked to the Roadster owner today and asked him about the pumping of brakes and he said that the when he goes down the track and has to stop/slow down there is no pumping of the brakes.

He only does it first thing in the am when he gets in the car. After that the brakes are great, the pedal is not soft and would be comparable to the dragster he owned

He has also been working on the problem and believes it is the Metric calipers opening up over a period of time.

[john858]

imo strange 1"no bigger .now on the rear calipers you need to run a steel line to them and just have a hose coming off the rearend to the frame for travel, if you don't you will have soft pedal issue from the hoses flexing and moving around.good luck

[robinhorn]

is your master on the firewall or floor?

Mine is on the fire wll in the stock location.

[robinhorn]

I as well was told to use hard line over braided. This did not make a change.

3 master coming from Wilwood thursday. 2 bad (Both brand new).

[john858]

thats why i said strange, one of the parts guys i use all the time can't stand wilwood stuff, he said there tech department was crap.(just what i was told)

[robinhorn]

thats why i said strange, one of the parts guys i use all the time can't stand wilwood stuff, he said there tech department was crap.(just what i was told)

They suck bad