After I had to put a new manual MC on the car last week, it got me thinking about upgrading the front 11" drums to 11" manual disc setup.

My main question is can I use my existing new manual drum MC if I want to swap out the front manual drums to a manual disc setup?

Thanks

I know that there are those out there that will flame me . . .HOWEVER, I did change the drum brakes on the front of my 1970 Chrysler 300Hurst to Disc and DID NOT change the dual reservoir master cylinder. The one thing you have to realize, is you need to be vigilant on checking the fluid level of the front reservoir, as the disc brake pads do wear and the caliper cylinders move to accomodate, thus reducing the level in the master cylinder. As long as it doesn't go dry, you are good. I know all this from REAL WORLD experience !! Sure it is a pain to keep checking the level, but if you have just put a new master cylinder on the car, why go to further expense ??? . . . just my two cents worth . . .

Cheers

Mark

Calipers require more volume than wheel cylinders. That is why ALL OEM have specific MC's for a disc/drum vehicle. Having a larger reservoir to account for pad wear is only one part of it and if you are religious about checking the level it isn't important, the volume pushed out of the MC is, which a drum/drum MC cannot match. Not to mention that if you do not remove the residual pressure valve from the front brake outlet you will have abnormal pad wear when using an all drum M/C in a disc application. M/C are cheap enough not to change it out to the correct setup.

I have a DD 65 dart with 74 A discs/10"drums with an alum 1&1/8" alum M/C with the original drum splitter/no prop valve. On paper it is mismatched but it stops perfect & no discernable wear on the pads. In your case I'd do the swap & leave the M/C as is & as noted keep an eye on the fluid but I wouldn't sweat it. When you get the discs on there have a helper press the pedal & see exactly how much the level drops

Thanks for the replies. I am going to contact Dr.D for the 11" parts. This is one project that I need to mke happen!

The drum brake MC will have residual pressure valves (RPV) in both exit ports, most disc setups will drag if a RPV is left in the front circuit so it should be removed from the MC's rear port. As noted, the fluid level should be checked more often when using drum brake MC.