I just had a very reputable repair shop do a complete drum brake overhaul on my 1956 Crown Victoria. Every component was replaced: brake line, brake hoses, new drums, new shoes, new 7 inch dual diaphragm booster, new dual master cylinder and all new drum brake hardware. Car stops okay however there still is what I consider an unsafe condition that they have tried and tried to correct to no avail.
The gap between the brake pedal and the accelerator is very narrow (maybe 0.5 inch) and when the brake pedal is depressed the first time, it goes approximately 1 inch past the accelerator pedal. After depressing the brake pedal the first time then pumping it again a second time, then the brake pedal will not pass the accelerator. When I was backing out of the garage, I attempted to stop the car. My foot pressed on the brake and when the brake pedal passed the accelerator, my foot also caught the accelerator and the car sped up instead of stopping. It scared the living hell out of me.
I realized what had happened and now know to be more careful when braking. I cannot let anyone else drive the car with this condition. The shop told me they tried every adjustment possible to correct the low brake issue. They are stumped.
Two short term things I am going to try is to change out the longer power brake pedal with the shorter non-power brake pedal and possibly putting some kind of spacer (block of wood?) under the brake pedal to prevent the pedal of going past the accelerator.

Does anyone have any ideas why the brake system is having this issue? Should I remove the brake booster completely and just have regular brakes and see if this is the issue?

Thanks,
Danny

First thing that comes to mind for me is we're the brake shoes arc ground to the drum. If not you may be stopping with just a small portion of the brake shoes. Arc grinding removes high spots on the shoes so more of the shoe area contacts the drum. Very few shops have an arc grinder. It's just one of those things that isnt done much anymore. Back when I was still working if you had a pedal that was low you would drive the car and step on the brakes to "burn" the linings into the drum so they fit better. Usually putting miles on the car and using the brakes they would wear in giving you a better pedal feel. Don't know if that's your problem that's what just comes to mind.


Dan      Kingman Az.      86409

How much travel do you have on your brake pedal. Something doesn't seem right as I have installed my own aftermarket brake booster on my 54 Merc., and I have very little travel. I wouldn't think you would have to pump your brake & have the travel come up with that booster?? There is only so much travel the brake linkage can go & it isn't much
    Anyhow, the aftermarket kit comes with  a flat rod which goes thru the firewall to your existing brake pedal & there are 2 holes in that to make the correct fit for the travel.  Neither would work on mine and I had to make my own bracket.  My brakes work great with this setup, and I would assume your new booster kit is very similar if not the same.   Mike

hter
I have a Master/Booster from MBM Brake. What they call a "Corvette" Style Master and dual Chamber Booster. Pedal travel before the Brakes start to engage is about 1". No where near the level of the Gas Pedal. I suspect there is a problem on yours with the Master Cylinder. Where was it purchased? I would contact the Seller and tell them the problem You are having. The fact that you can pump the Brake Pedal and get a higher Brake level is something caused by the Master. Many 55/56 Fords have been converted to Power Assist and don't have problems like You are describing. As You mentioned I would NOT be driving this until the problem is corrected. I installed this same Setup on my Friends 55 with Drum Brakes and had no problems. Mine is Front Disc Brakes off a Granada.

  

If the pushrod is too short, the pedal will be too low.  But that doesn't account for having to pump the pedal.


Lawrenceville, GA

I would assume the Shop bled the Master on the Bench prior to installing. That is recommended by MBM who supplied mine. Gets the Air out of the Master.

  

This may not be the placed, but why are so many Ford guys obsessed with altering the brakes on their Fords. In 1956 Fords had a very good system which was stated in the reviews at that time. As I understand typical power brakes cannot be easily pumped and the fender power assist can if necessary. I have stock drums and a singe master and am very comfortable with the system. I adjusted them with every oil change which is normally once a year and believe that is the key. I have considered the fender vacuum assist but not as yet committed to it. Millions and millions of miles were driven safely with no power, single master cylinder, and drum brakes. To me a vacuum can on the firewall covers up a nice engine and heat from the exhaust header doesn't do it any favor... Sorry for the rant.

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

For me it's a matter of horse power and modern speeds. "I" will have double the stock horsepower when complete.
As for "they", higher speeds and lighter cars =s shorter stoping distances for most. I want to be able to stop as quickly as I am able to go. I will be driving my car as often as possible and with all the crazy ass drivers on the road today.....well.....

Rowen
55CV
Woodland, Ca

I installed Disc Brakes and Dual Master with Booster. I would never go back to stock. Mines just a Driver but I was never comfortable with the way the Stock Brakes worked. Brakes in general have come Light Years since 1955-56.

  

Danny
A way to test if the brake booster is operating is to turn off the engine ( car parked ) and pump the brakes several times. Hold the brake pedal down while starting the car. Brake pedal should depress 1/2 inch. If you pass this test then the geometry of the brake pedal may be wrong. Did the car always have power brakes? Tell us more. Is it a kit?