Dual Master Cylinder with drum brakes.

[NYsquarebird58]

I have a ‘60 with power drum brakes (booster on the firewall).Can I replace just my master cylinder with a duel master cylinder?

I will be doing the disk brake conversion up front in the future, but I busted a hard line and I figured while redoing all the brake lines, I should change over to a dual master cylinder setup for added protection.

You would have to find a drum/drum dual reservoir MC (rebuilt) from a 66/ FORD or possibly later MAVERICK. They were available manual or power.

[Jimz Bird]

Just curious, could a disc/drum MC be used? The one chamber would be larger but would that be a problem? If it could be used that would save buying another one when doing the disc conversion.

Also on Manual and Power differences, it seems that most of the Power MCs have a very short pushrod chamber and the Manual MCs have one that is a lot deeper.

There are cautions about using a Power MC in place of a Manual - on the firewall - due to the chamber being short and the pushrod could fall off.

I'm guessing it is because most that have power brakes have the MC in the front of the booster. That is opposite some of the TBirds (all 55-57) and some of the Square Birds (Under dash booster I think - need others input on that) which have the booster after the MC.

[Howard Prout]

Originally Posted by Jimz Bird

... That is opposite some of the TBirds (all 55-57) and some of the Square Birds (Under dash booster I think - need others input on that) which have the booster after the MC.

Squarebirds that have the Kelsey-Hayes booster have a tab on the brake pedal arm that presses on switch on the K-H booster that opens a valve and uses vacuum to pull on the brake pedal arm - power assist. The pushrod goes from the brake pedal arm to the MC. The K-H unit is off to the side. The MC for K-H power brake system has a 1-1/16" bore rather than a 1" bore for non-power brakes thereby requiring less travel but more pressure on the brake pedal, which is more than overcome by the power assist.

[jopizz]

A dual M/C from a 67-68 Mustang should work. I would use a drum/drum M/C rather than a disc/drum since you have no proportioning valve.

[Jimz Bird]

Thanks Howard. I understand it now.

[Jimz Bird]

Originally Posted by jopizz

A dual M/C from a 67-68 Mustang should work. I would use a drum/drum M/C rather than a disc/drum since you have no proportioning valve.

Ahhhh, I think I have it now.

It is not just the bowl size but that the Disc/Drum MCs also "generally" have proportioning built into the rear circuit of that MC.

Close?

[Dakota Boy]

I used a drum/drum master cylinder for a 67 Mustang with drum all around and no power assist. I think it was about 50 bucks from NAPA.

You will want to get one with the same bore diameter as your single master that you are replacing.

Before I replaced the single master I also made dang sure the parking/emergency brake worked.

[NYsquarebird58]

Originally Posted by Dakota Boy

I used a drum/drum master cylinder for a 67 Mustang with drum all around and no power assist. I think it was about 50 bucks from NAPA.

You will want to get one with the same bore diameter as your single master that you are replacing.

Before I replaced the single master I also made dang sure the parking/emergency brake worked.

I was reading your thread on your conversion, but I saw that you don't have a firewall mounted brake booster like me. Would I be able to use the same master cylinder that you used on my booster?

How did you get yours to bolt up? it looks like the mustang MC's are two bolt instead of 4. Here's the link to one for sale on Summit Racing: http://www.summitracing.com/parts/AAZ-10-1488/All/

[Dakota Boy]

It bolted up.

I was nervous about it not working, and so I took the old one to NAPA to see if the bore and the two bolt holes lined up.

Get one with the same bore diameter as you have on the old unit now. Dont get one that is bigger or smaller, or you'll be sure to have some brake pedal issues.