Sign in to follow this  
Tcarrasco84

1955 Buick brake question

Recommended Posts

When he said 1" I think he means the linings, the shoes, not the lines.

Neither. It's the diameter of the master cylinder bore. 1" is very common for GM drum brake master cylinders.

Share this post


Link to post
Share on other sites

I understand your desire for a dual master cylinder.

We know now that,

Your brake lines are something smaller than 1"

And

Your brake linings are something larger than 1"

I have posted links to others that have gone the dual cylinder route.

Good luck to you,

Bulldog

Share this post


Link to post
Share on other sites

hi joe, you're mistaken about how the treadle vac system works, it does not apply pressure to the pedal arm, it acts like almost every other power brake set up, it allows the driver to apply less foot pressure on the brake pedal, and with vacuum boost, applies more pressure to the master cylinder to move brake fluid out to the wheel cylinders and apply the brakes shoes to the surface of the brake drums. a hydravac takes standard master cylinder hydraulic pressure, and with a vacuum booster, applies more pressure to the wheel cylinders with the hydravac master cylinder. i have never in 40 years, seen any kind of power brakes apply pressure to the brake pedal's arm. charles coker, 1953 pontiac tech advisor.

Share this post


Link to post
Share on other sites

here is what a treadle vac set looks like, the location of the pushrod behind the pedal is different than later powerbrakes set moving the pushrod up onto the pedal's arm, but everything works the same way as i explained in my earlier post to joe. charles coker, 1953 pontiac tech advisor.

post-32395-143139322462_thumb.jpg

post-32395-143139322486_thumb.jpg

Share this post


Link to post
Share on other sites
i have never in 40 years, seen any kind of power brakes apply pressure to the brake pedal's arm. charles coker, 1953 pontiac tech E]

Charles,

The booster on the 61-63 Skylark and F-85 is located under the dash and applies force to the pedal arm, not the M/C directly. In any case, you cannot compare a treadle vac to a modern diaphragm style booster. An 8" single diaphragm booster will provide only limited assist unless the engine produces a VERY high manifold vacuum. There's a reason why GM used an 11" booster on most of it's large cars.

Share this post


Link to post
Share on other sites

if someone wants to compare a treadle vac to any other type of power brake system, it is perfectly ok to compare. and most of GM's LARGE CARS had treadle vac power brakes from 1952 to 1958. charles coker, 1953 pontiac tech advisor.

Share this post


Link to post
Share on other sites

Keep in mind that if you use any booster other than the treadle under the floor you will have to change the brake pedal to a manual brake model. The brake pedal for a treadle is nearly 1 to 1 ratio and I guarantee you will have a difficult time stopping regardless of the booster. The manual brake arm is about 6 to 1. After having my booster rebuilt twice by the "best" treadle vac rebuider in the country and having it leaking vacuum both times I went to manual. Works great, Rich

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this