55 ford brakes and tires

good morning all, I have a couple of questions I hope someone can help with, first the brakes on my 55 ford, I am using a new ford m/c, new lines, new disc kit on front, speedway prop. unit, all new brakes on rear, I have bled everything many times, the car stops but I have to stand on the pedal, the car has a 390 in it and didn't want to use a booster if I don't have to, second anyone with a 55 (mine is a customline) have wheel and tire sizes, I have 15/7 with 215 70 on it now, but would like to use a taller tire, had a 235 on a 8 rim to try, rubbed, thanks, steve

 

Disc brakes require higher pressure and that means you gotta have a booster

Use 75 size tires instead of 70

 

What was the MC's original intended installation? You may have created a combination that isn't getting enough pressure to the brakes without having a booster behind the mc.

There were some late 60's early 70's Corvette manual brake disk/drum and disk/disk master cylinders that guys used years ago when we started converting to disks on our older cars that worked quite well.

 

I've got 235/60/15s on the back of my 56 but I've got a narrowed rear end in mine and only 2½ inches of offset on the wheels.
Swing by the 52-59 Ford Group and see what some of them are using on their cars.

 

thanks all, I guess I need to measure for a booster, I am running the stock rear for now, I am old, don't know if changing is worth the trouble for me, thanks

 

You absolutely can get disc brakes to work without a booster. That's hogwash. There are many factory apps out there that used just that. Even into the 80s. I had an S-10 pickup that was manual disc/drum from the factory. You just need to look around a little. You really need to find an OEM app that sort of mirrors your app however. By that, I mean that you need to find something with similar piston size/config in the front and wheel cylinder bore in the rear. You can sometimes have a bit of a gotcha with the pedal ratio as well but I wouldn't suspect that at this point.

On the tires, I can tell you that you can get 235/70/15s to fit, but just barely. You'll need to raise the rear an inch or so over stock and use a 7" rim with a good bit of backspace. I think mine are right around 5" of backspace. Hope that helps...

 

I have had over a dozen chevelles and cameros with disk drum and no booster just use a proporning valve..and match Master cyl

 

I have 4 wheel discs on my '56 Mainline without a booster. I do use a proportioning valve and a dual chambered master cylinder.


Posted using the full custom, V8, 4-speed app, rolling down highway 41.

 

Sold brake kits for years for 1949-64 Fords, disc brake kits work fine without a booster. I would use a proportioning valve and make sure your master cyl bore is large enough.

 

thanks everyone, I am using the speedway 1" bore ford type m/c and the speedway adjustable prop block with brake light switch, the brakes are from tom's classics uses a chevy truck cal with tbird rotors, drove it yesterday it stops without pulling but take a lot of pressure, used the same kit on my 63 galaxie with a chevy type m/c and prop valve, not like power but much easier to stop, thanks steve

 

All you need is a master cylinder for a Granada/Monarch. They are a dual master, and works great!

 

You don't want a LARGER master cylinder bore.........in fact the 1" may be too much as it is. A smaller bore MC will produce more hydraulic line pressure for a given amout of pedal pressure....but at the expense of slightly more pedal travel.

I used a '67-'72 Mustang 15/16" MC on a '47 Ford which had BIG GM calipers ('71-'76 full size car), 12" rotors and an 8" Ford rear end with 10" brakes and whatever size wheels cylinders, probably 3/4" or 7/8"....and had excellent braking with no booster. I don't know what your caliper bore size is, but it is a factor in deciding MC cylinder size, especially when not using a booster. Also, rotor diameter is a contributing factor.

I do not believe a proportioning valve has any bearing on your high pedal pressure.

 

All '67-'72 Mustangs used a 1" master. The first use of a 15/16" master was '73, along with the '74-'78 M2. Point is you may have had a 1", thinking it was a 15/16", maybe?

 

That project was about 5 years ago, and to the best of my recollection, I purposely selected a 15/16" master cylinder precisely because I wasn't using a booster.

But whether or not I am mistaken about the bore size, the point I made remains valid. Specifically, that the OP's problem with excessive pedal pressure likely can be alleviated by selecting a master cylinder bore size that provides more line pressure than he currently is generating with his present MC, and that bore size would have to be smaller, not larger, as hinted at by another poster.

Apparently you did not find fault with the principle I was Illustrating.