[kreuzn1]

I'm building an old school rod and I need help determining what master cyl. to use. It will be mounted on the firewall, will not have a booster and I would prefer it have dual reservoirs. The front brakes are '46 to '48 Ford 12'' and the rear are 11'' Ford F-100. Does anyone have any thoughts on this? Please don't tell me to use discs. That is not an option.

[matt167]

'67 Mustang disc brake M/C's are used in a lot of disc brake hotrods.. how about a '67 Mustang Drum brake M/C... IIRC the wheel cylinders are 1 1/8" bore front and rear on a '67 Mustang

[powerrodsmike]

You can't just say that any particular year or model of master cylinder will work without knowing what the rest of the system is ..... .Size does matter here.
rarely are the same size wheel cylinders used on the rear as on the front. Manufacturers engineer the brake system with smaller W/Cs in the back for proper braking bias.

What are the bore sizes of the wheel cylinders in the brakes you have.?

The bore size of the master is determined by how much pressure it needs to make, how much fluid it needs to push at that pressure, and how much room you have to work with for a pedal ratio.
Also, knowing how tall your firewall is can make a difference..a short firewall will make it hard to make a pedal with a 6 or 7:1 pedal ratio that will give a long enough stroke to work certain size brake wheel cylinders.


Later, mikey

[matt167]

Originally Posted by powerrodsmike

You can't just say that any particular year or model of master cylinder will work without knowing what the rest of the system is ..... .Size does matter here.
rarely are the same size wheel cylinders used on the rear as on the front. Manufacturers engineer the brake system with smaller W/Cs in the back for proper braking bias.

What are the bore sizes of the wheel cylinders in the brakes you have.?

The bore size of the master is determined by how much pressure it needs to make, how much fluid it needs to push at that pressure, and how much room you have to work with for a pedal ratio.
Also, knowing how tall your firewall is can make a difference..a short firewall will make it hard to make a pedal with a 6 or 7:1 pedal ratio that will give a long enough stroke to work certain size brake wheel cylinders.


Later, mikey

I know.. but with the limated amount of information given, I suggested a common master cylinder.. but that's also why I gave the wheel cylinder bore sizes the Mustang uses but forgot to add that the '67 Mustang manual Drum/drum M/C is 1" bore

just guessing, the larger brakes probably use 1 5/8" bore wheel cylinders.

[kreuzn1]

Front cyls. are 1 1/4'' dia. on front shoe (which is the larger shoe) and 1'' on the rear. Rear brake cyls. are 7/8'' dia.

[powerrodsmike]

As Matt suggested, I'd use a 1" . If you are using up too much MC stroke go to the next size up. Make your pedal so you can change the ratios if you need to, I'd do 6:1 and 7 : 1 , that will give you some room to play around with the bore size and ratio to get a good feel.

Get the master cylinder from a 4 wheel drum brake car, it will have the residual pressure valves in both circuits already.


Later, mikey

[kreuzn1]

Sounds good. I'll give it a try. Thanks.