Brakes

[alvin stadel]

I have had huge brake issues on the 57 RHT that I just finished.  I have got it so it will stop very good, but it still isn't right.   I hope this will make since,  I am not sure if this is part of my problem or not. The 2 pins that go from the shoes to the brake cylinder are at a angle, not running straight across from the shoe to the cylinder. When the brakes are applied the pins do push against the cups in the cylinder, but I am wondering if they are not being activated all the way.  No matter what I do I can not get the pins to run straight, any ideas. I am beganing to wonder if they sent me the wrong shoes.  One more thing, this is a power brake sysetem, and if the car is not running I have no brakes. I have a electric vaccume  pump that helps a bunch, but if it is not running I have no brakes.  Every thing is new

[hiball3985]

How much of an angle? A picture would help..

[alvin stadel]

Maybe 5+ degree. I will have friend take a picture and post it, but that won't be until next week

[John Palmer]

What was changed since it worked OK?  Sounds like a mismatch between the wheel cylinder, backing plate, and shoes.  Were any of the three items recently replaced?  Is the wheel cylinder upside down?  Just guessing without a photo.

John

[SkylinerRon]

How are you seeing them? Drums off? New shoes cam ground?
Did you know one shoe activates before the other? Be sure each wheel has one long and one short lining with all the shorts toward the front of the car. The shoes only need to move a small distance to engage if adjusted correctly.
Goodluck,

Ron.

[hiball3985]

I don't think that small of an angle would be a problem. Last year when I did the front brakes on my truck I noticed the pins weren't exactly horizontal, just a slight angle but it brakes fine with no problem. Do you still have one of the old shoes to compare?

[alvin stadel]

John, everything is new, and installed correctly, Ron, shoes are installed right, and I am looking it it with drums off.  Its like I said in my first post, I do have brakes but only if vacuum booster is running. To me I should still be able to stop the car running or not.  This is a power assist system so why won't it stop like the rest of my cars do with out power brakes?  The brakes have been bled many times, good fluid and hard pedal, so to me they should stop at anytime. That is why I asked about the pins not being horizonal. This damn thing has me about ready to commit  harry carry.

[Hoosier Hurricane]

Power brake master cylinders are 1 1/8" diameter, manual brake ones are 1".  A power brake master on a manual brake car is extremely hard to stop, you cannot even slide the old 7.50x14 bias tires.  Don't ask me how I know that.  I assume a power brake with no power would act the same.  Hard pedal with very little braking.  You may not have a problem, Alvin.   John

[John Palmer]

Power brake master cylinders are 1 1/8" diameter, manual brake ones are 1".  A power brake master on a manual brake car is extremely hard to stop, you cannot even slide the old 7.50x14 bias tires.  Don't ask me how I know that.  I assume a power brake with no power would act the same.  Hard pedal with very little braking.  You may not have a problem, Alvin.   John

AGREE.

But it's even worse than just the difference in cylinder diameter.  I currently have my booster assembly removed from the car.  The power booster has a "three inch" increase in linkage leverage, compared to a direct manual system.  Without any power assist, it might slow the car down, but your going to have to really stand on the pedal.

[djfordmanjack]

Interesting info here. What do you guys think is the reason for that large diam of a mc ? would the power brakes feel to 'touchy' with a std size m/c?
lock up at the smallest amount of foot pressure?
maybe people weren't so much aware of the wild braking force of a power assisted pedal in 1957 , as we are getting used to today in modern cars? ( not me, because i hate driving modern cars)

Interestingly enough my std brakes 57CS wagon really stops very well and I could easily lock up the tires, even though I am not a 'large size' person.

I have an oem 57 Ford brake booster setup for my Del Rio project and I am thinking if I could use it with the factory 1" m/c.

[hiball3985]

Good question Gunter. I've seen other cars with 1" master and power so it may be possible.
The first car I drove with power brakes was a 55 Oldsmobile, Hit the brakes, locked up the wheels and I thought I was going out through the windshield. All the cars I have owned over the years not one has had power brakes..

[lalessi1]

My guess is that it has to do with the amount of fluid that must move to actuate the brakes and the travel/mechanical advantage of the booster design. A larger master does not have to move as far as a smaller one.

[dgasman]

It?s the ratio of the power brake pedal assembly  compared to the non power assembly. A 1inch bore with the sure swift PB will give you a very soft pedal feel , like it has air in the system. A 1 1/8 inch bore on the standard brake will give a very hard pedal. The pedal is very low on the sure swift system compared to the standard brake.

  With the sure swift system even having the brakes out of adjustment will make the pedal almost hit the floor, that?s how low the pedal is. I am running front discs brakes with mine and can tell when the rears need to be adjusted because the pedal starts to get low .
 
The sure swift system is a adequate PB system , it?s nothing like a more modern PB system as it still has more brake feel . Not hard but not real soft .

My ranchero will stop with no vacuum but the pedal is really hard , like standing on a rock , lots of leg force

[dgasman]

Alvin, I have a question. Do you have the vacuum tank on your PB system? Is the check valve on the tank working so it will hold vacuum with engine off ? I ask because you say you have a electric vacuum motor in the system and it should not need it unless you have a big cam or low idle vacuum. You should get 1 to 2 good assist pumps of the brakes with the engine off .

[dgasman]

You got me wondering about the wheel cyl pins so I had to look at my brake assembly and the pins are not straight out . Here is a picture