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There is, in the case of a 65 Mercury Comet I'm helping restore,, a difference in pedal leverage if that vehicle was built with power breaks, or manual brakes.  That is, the MC push rod is positioned much higher on the brake pedal arm than if that vehicle was equipped with power brakes.  I just wanted to say there can be some not so obvious design differences.    Also, after a panic stop in my 64 F100 which has manual/drum brakes, a sound was produced I haven't heard in decades,-  screeching tires from hard braking.  Antilock brakes are the other piece of the modern brake equasion.  The truck stopped very well and straight with out incident and it doesn't take a lot of pedal pressure/effort with the stock design. Just some more food for thought....

64F100 57FAIRLANE500

Fortunately, I have had only one panic stop - doing 65 when I came over a rise and found traffic dead stopped in front.  Brakes worked very well.  I might add that I have a 9 inch rear with later TBird/truck brakes




54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

1st-gen. Mustangs/w 4-piston KH calipers had 14" rims. 

14" wheels

I agree, pedal ratio makes a big difference. 6 to 1 and a MC of 7/8” or smaller normally do not need a booster. I remember my dads new 55 sunliner he had the dealer add a Bendix booster. It was a lot more sensitive than the 56 Victoria which he didn’t add one.
When I changed rear ends in my 56 the brakes came off a vehicle with power brakes and I changed the wheel cylinders to a smaller size. Also 4 piston or 6 piston calipers seem to work fine without one. There are a lot of options and opinions.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I too have the Granada front discs and dual master cylinder which I did 10 years ago. I'm not 100 % happy with that setup as I've had to make a few panic stops and thought car should have stopped sooner in that situation. I find that I have to pump the brakes  to get a good firm hard stop. Of course , in a panic situation I don't have that luxury.  I keep going back to Gil Baumgartner's comment where he stated to me in an email that disc brakes need approx. 1200 psi to be fully effective.

It sounds more likely you have a mis-match of parts and/or incorrect adjustment/system bleeding. That line pressure is generated by caliper style/piston size chosen, MC type, pedal ratio and amount of pressure you can put on the pedal. Power assist only makes it easier to achieve that brake line pressure. Factory cars also came through with manual disc/drum.

You have a GRANADA disc swap on your BIRD now? What size wheels?

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Thanks for your input Paul,  I too have the Granada front discs and dual master cylinder which I did 10 years ago. I'm not 100 % happy with that setup as I've had to make a few panic stops and thought car should have stopped sooner in that situation. I find that I have to pump the brakes  to get a good firm hard stop. Of course , in a panic situation I don't have that luxury.  I keep going back to Gil Baumgartner's comment where he stated to me in an email that disc brakes need approx. 1200 psi to be fully effective. I have talked to Master Power Brakes in No. Carolina and they recommend a 7" dia dual booster with a 1-1/8 " bore master cylinder for my application of front disc and rear drums. They also recommend a combination valve which I already have. I have already relocated the battery to the trunk to make room for the booster tank. Master Power has stated  that rework to the booster tank mount bracket will be required to ensure the booster tank does not contact the  tbird aluminium valve cover..I should have said the tbird under dash mount channel / firewall master cylinder mount will have to be  reworked.  So I'm going to go for it !  Thanks again  RJ Palmer

I did a Granada conversion on my 54 Ford.  Went non power.  Used the Granada dual master for non-power brakes.  Brakes improved with stopping and don't miss the power set up at all.

A friend with a 56 Bird just went to front discs, non power.  As far as I know, he is very happy with it.  I think he used the 4 piston calipers.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Disc brake calipers are designed to operate at higher hydraulic line pressure than original drum brakes, as a result it is very beneficial to have a power brake booster. These steps are written presuming you have a power booster on your car. If not, the brake fluid lines would be slightly different. A booster is highly recommended. Even with a booster these brakes will not give you the feel of the disc brakes on your new vehicle, it still takes a bit of pedal pressure. The biggest advantage is the straight, true stopping, and the resistance to fade.

SOURCE - https://www.ctci.org/disc-brake-conversion/

A MIDLAND BOOSTER is designed for one circuit only as was common in pre-1967 cars (SGL RESVR MC). To keep the disc conversion somewhat OEM appearing, the front disc circuit (primary reservoir) will be plumbed through the BOOSTER HYD CYLINDER for disc power assist and the rear drum circuit plumbed straight from the MC secondary reservoir as they require less line pressure their being self-energizing.

The original kit design included different size rear wheel cylinders and was later changed to a universal PPV. Both methods seem to be hit and miss on brake bias. The booster will give enough assist to be noticeable.

The nice thing about this conversion is that the KH 4-Piston Caliper can be adapted to the OEM spindle (and keep original 14" wheels - 57 BIRD) and can be easily changed back to 4-wheel drum if the car goes to a dedicated restoration.

CTCI Install Photo Showing Rough Plumbing -

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