Which master cylinder?

[79loserbluebu]

Hey everyone, I'm building a new car with my father. It's not really going to be a track car but just a cruiser with some modern upgrades. It is a 66' Impala station wagon and I am swapping in an LS1 with a 4L60E trans.

Anyways, I am using the big brake CPP kit up front and rebuilding the factory rear drums in back. The car was originally a manual drum/drum and obviously it needs to be converted to disc/drum

So what I have so far is a new brake line set coming for the car that is made for disc/drum, not really sure where the lines will be placed by the master cylinder but I will find out once they arrive.

I ordered a master cylinder from a 98+ S10, however the brake lines were on the passenger side of the master and that wasn't going to work.

So then this morning I ordered a master from a 97+ Corvette, which appears to be the same looking master just with the line ports on the driver side of the master cylinder.

For the booster I have one from an 05' Astro van and have a steering box from an 87' Grand National, and will be using lines from probably the Astro van and will have them cut down if I need them to be.

So my question is, should I look for a disc/drum master cylinder and return the Corvette one? I am worried since the Corvette one is disc and disc it may be an issue. I am using the disc/drum proportioning valve kit that all of the companies sell, CPP, Ecklers, Hubbards, etc.

I am also confused on which way the master cylinder to prop valve lines need to be ran. Some places I have seen them needing to be crossed, and others to be ran front to front and back to back.

Sorry for the long post and thanks to anyone willing to give advice on a grocery getter

[dontlifttoshift]

Use the disc/disc master.....I am assuming you have done the math and that bore size will work for you.

Throw away the brass combination valve, nothing but trouble unless you are stock.

Use an adjustable proportioning valve and a 10 psi residual valve in the rear for the drum brakes.

[andrewb70]

Hey everyone, I'm building a new car with my father. It's not really going to be a track car but just a cruiser with some modern upgrades. It is a 66' Impala station wagon and I am swapping in an LS1 with a 4L60E trans.

Anyways, I am using the big brake CPP kit up front and rebuilding the factory rear drums in back. The car was originally a manual drum/drum and obviously it needs to be converted to disc/drum

So what I have so far is a new brake line set coming for the car that is made for disc/drum, not really sure where the lines will be placed by the master cylinder but I will find out once they arrive.

I ordered a master cylinder from a 98+ S10, however the brake lines were on the passenger side of the master and that wasn't going to work.

So then this morning I ordered a master from a 97+ Corvette, which appears to be the same looking master just with the line ports on the driver side of the master cylinder.

For the booster I have one from an 05' Astro van and have a steering box from an 87' Grand National, and will be using lines from probably the Astro van and will have them cut down if I need them to be.

So my question is, should I look for a disc/drum master cylinder and return the Corvette one? I am worried since the Corvette one is disc and disc it may be an issue. I am using the disc/drum proportioning valve kit that all of the companies sell, CPP, Ecklers, Hubbards, etc.

I am also confused on which way the master cylinder to prop valve lines need to be ran. Some places I have seen them needing to be crossed, and others to be ran front to front and back to back.

Sorry for the long post and thanks to anyone willing to give advice on a grocery getter

I believe there is another version of that S10 MC that has the fittings on the proper side. What was the PN?

Andrew

[79loserbluebu]

Thanks for the responses guys.

I ordered the brass one and the bracket and pre bent lines because it was convenient but if they are aheadache ill go with an adjustable that way its cheaper too. Any good brand of residual valves and a prop valve to use? Also for the front brakes do I need a valve or residuals up front or just a t block to split left and right?

I thought about using a master from a late model Silverado with disc/drum considering the cpp big brake kit uses Silverado calipers but it is very bulky and the reservoir is huge.

Andrew I know which one you are talking about I believe it is for right hand drive trucks. The vette one was the same price with a nicer looking reservoir

[MCB Matt]

I am sorry, I just have to ask, why not use the correct bolt on booster/master/prop combo that the pre-bent hardlines bolt right up to?

Also, keep in mind, with that brass/gold prop valve you have, you can NOT pump and hold bleed the brakes or else the front will build pressure before the rear typically and cause the valve to "pop" which will slide the pin inside the valve to close off about 90% of the fluid flow to the rears and you will be chasing problems forever.

There are a few different ways around this. For my customers that do a lot of conversions they just use a bolt that screws in place of the white plastic switch at the top of the valve. You grind it down to a point and screw it in lightly and it holds the pin in the "center" which you can see when you take the switch out. The other way... and best way is to pressure bleed the system using an affordable mityvac system....

You can test the valve to see if its "popped" by using your multimeter and checking for and open or closed signal from the pin in the middle on the white switch to the body of the prop valve, that's what it does to turn the BRAKE warning light on it the dash... The pin slides, making contact with the switch pin, closing the ground... So you want an "OPEN" signal from your meter.

Matt