Disc/Drum brake question....

[Silver Streak]

If you have a master cylinder/purportioning valve from a disc brake setup that goes to a drum brake rear.. is that still going to work normally?

I have the master/purportioning valve from a 95 camaro to match up with the pedals... but can't find/dont want to spend the money on a new disc rear end right now... so would this work in my 87 T/A?

[mark21742]

no it won't, it cuts some line pressure to the rear.
check auto zone or advance auto, you might be suprised at how low prices are (just checked advance online and they have them for under $50)

[Silver Streak]

Ok, here's the story... I'm doing an LT1/6-speed conversion into my 87.. so I needed the engine, trans, pedals, master/purportioning valvue, etc for the swap. I've been trying to find a disc rear... but so far no luck. A 3rd gen one will not match up with the pedals, so how much pressure loss are we talking?

[mark21742]

Ok, here's the story... I'm doing an LT1/6-speed conversion into my 87.. so I needed the engine, trans, pedals, master/purportioning valvue, etc for the swap. I've been trying to find a disc rear... but so far no luck. A 3rd gen one will not match up with the pedals, so how much pressure loss are we talking?

ok lol I'll answer two ways to be sure I give you the right answer.
if the car the master cylinder came off of had front disc/ rear drum it will work on a front disk rear drum car of a different year.
if the mastercylinder came off of a front disk rear disk car and you are puting it on a car with rear drums and it bolts up you can use it but you would need to buy an adjustable porportioning valve and adjust the rear presure down till you got the best results....then if you get your rear disk setup, just ditch or adjust the valve to meet your new needs.
it might take fabing up a flat bracket but you could go to the junk yard and try a set of chevy lumina rotors and calipers...bracket would go from where the old drum backing plate bolted in up to the caliper

[joejenkinsglass]

drum brakes use more pressure than disk. So you can use a disk/drum master to operate a disk/disk set-up (with an adjutable valve) but you cannot operate drum brakes with a disk master. The disk only take about 1/5 the pressure of a drum.

hope that helps

[mark21742]

drum brakes use more pressure than disk. So you can use a disk/drum master to operate a disk/disk set-up (with an adjutable valve) but you cannot operate drum brakes with a disk master. The disk only take about 1/5 the pressure of a drum.

hope that helps

is that the way it goes? i remembered the pressure difference but its been years since i messed with brakes.

[joejenkinsglass]

is that the way it goes? i remembered the pressure difference but its been years since i messed with brakes.

pretty much