disc brake master cylinder?

I am doin somethin a little off the wall. I have disc brakes with a lowering spindle on a 66 skylark. The car was too low (draggin headers.) I decided to through the drums with factory spindle on for a while til i can find a better situation. Question is.... Can I run a disc brake master cylinder with drum/drum? or will it blow out the wheel cylinders? any help appreciated!!!

 

It will work, BUT, depending on the size compared to the one for the drums, you might have a hard pedal or a sensitive one.

 

You need to replace the proportioning valve with the drum brake distribution block. Otherwise you will be locking up the rear brakes all the time.

 

The answer to your question is yes, you can use a disc brake master with drum brakes. If the bore sizes are equal, the disc and drum masters will produce the exact same pressure. You will probably have to add a residual valve to the front drums, as your '66 brakes might not have cup expanders in the wheel cylinders. More info is needed as to what brakes you have on the car, i.e., disc/disc or disc/drum, and what kind of master, power or not, etc. Also, was your car originally equipped with a dual master, as most were still single systems until '67.
Bob

 

I added the dual master cylinder when I put on the disc brakes. It is a manual brake set up w/ a camaro master cylinder.. the brakes were a newer camaro. The brakes worked great it was just to low for the headers. I used aerospace componets disc brakes on my chevelle with the original spindles I intend to do the same here when money comes around... That is the main reason for trying to keep the master,trying not to do everything twice!!

 

I would still add a 10 lb. residual to the front drum brakes, max out the adjustable prop valve, or remove the factory "fixed" valve, if so equipped.
Using a disc/drum master in a drum/drum system has some advantages. One, they are easier to find new or rebuilt because they have been around since the late 60's. Two, you won't have to change masters if and when you upgrade to front discs.
Bob

 

Thank you!!!