Can someone please give me a brake....answer?

Figured i'd ask this question on here instead of spending alot of a customers money. We have a customer with a beutiful 1962 ford fairlane that has been restored a long time ago and has been in a ford showroom for years. The power brakes almost put you through the windshield, just light pressure applied and it will lock the wheels.We have tried changing the shoes,checked the cylinders for the right dia. cups,changed the master, changed adjustments tite and loose nothing seems to make it better. Has anyone ever ran into this? Its hard to get a booster so would like to make sure before ordering one.The booster has been replaced with a rebuilt when it was done in the rebuild. Any help would be great thanks. Dave

 

You might try a restrictor orifice in the vacuum line between the manifold port and the booster. Slowing the vac application just may correct the sensitivity of the booster.


Ray

 

On Mopars, there is an adjustment for the length of the rod between the brake booster and the master cylinder. It adjusts the amount of preload on the master cylinder. You probably need to shorten that rod length. A little adjustment goes a long ways.

If you can't see any adjustment, try putting a flat washer on each stud between the master and the booster and see if the brakes work better (or is it less better )

If the washer makes a difference, you need to shorten the internal rod the amount of length of the thickness of the washer. Gene

 

sometimes my o/t 70's truck does that. usually after a good rain storm or humid morning. we concluded that the braking surface area was getting rusty and creating an extremely grippy surface. is the issue ongoing no matter how long you drive it?

 

check the pedal, sometimes there are 2 different sets of holes for the brake pushrod, on power brakes you dont need as much leverage, might have the wrong pedal ratio going on or something.

 

Rick's reply is what firs came to mind. I recall that power brake Fords were very touchy in the early 60's.

 

It is the booster. I had a Pontiac like that.

 

the big cars were touchy, don't remember fairlanes with power brakes until 65 or 66, good luck

 

Many of the cars of that era had brakes like that, early '60s Olds and Pontiacs would do that. You really had to have a soft touch with the pedal.

Bob

 

my 66 did the exact same thing when i got it, manual pedal with a booster. if you looked at the pedal it would lock up the tires. redrilled the hole to 5 to ratio and it was much better.

 

My 48 was like that when I had a firewall mounted booster out of a donor rig in it. I was used to it and didn't have a problem but when someone else tried to drive it they usually locked up the brakes. It either had too much booster or the wrong pedal ratio as I think I mixed and matched booster and pedal when I put it together.

 

Try replacing return springs on shoes, when these get weak any pressure to the cylinders just slams the shoes against the drum.

 

Is this a push through firewall mount unit or a remote one. I don't remember just what ford used in that era. GM stuff in the 50s early 60s were super sensitive , do check pedal ratio.

 

I added a used power brake booster to my OT Chevelle that I built it from a basket case. Factory booster and all correct Chevrolet parts. No streetrod parts. It was a bitch to drive. I finally bit the bullet and paid top dollar for a concours restored booster. That was it. Tires no longer locked up. What a relief.

 

Thanks for the hints Ill try to get the car back in next week,its always the same in all weather and the springs were replaced when we did the shoes.They're are two holes on the pedal, its on the bottom one on a bad angle i'm told. The pedal does say power brakes on it so i believe its the right one.This car is as beutiful underneath as it is on top and i believe it to be all original. Thanks again and if we do fix it i will post the fix.Dave

 

Touchy brakes are typical of a sixties car with power drum brakes. The drums are self energizing, discs are not. So discs are more progressive.

The secret is to pivot your heel on the floor and apply light toe pressure. This makes it easy to modulate the braking.

Or, they could be messed up. Hard to tell from here.

 

like he said. period. had one to

 

Hey guys, well its been almost a year since I posted this problem and the guy just brought the car back. He had it in storage and has only driven it once because he hated the way the brakes locked up when applied.Well it ended up being a booster. Thanks again for the suggestions. Its like a brand new car and the man loves it now. Hopefully he will enjoy it more. Dave

 

What is going wrong inside the booster to make the brakes act this way?

 

^^^^....what he said....

 

Got me....and I'm an ASE master tech. I've never had one apart just always replace them.

 

Not necessarly anything wrong internaly ,the same size unit can have different bores on the hydralic side depending on the orignal app. Where I worked years ago the shop rebuilt these things and the ID tag number was needed toget the correct replacement. A smaller bore will give a higher line pressure giving touchy brakes.

 

the bigger the diameter of the booster the more assist it gives ( more area for the differntial of pressure ) , if its a small one they ussually double up the chambers to get the area needed . the older ones were too big and with a reserve canister ( which ford used for all the accessories they were a little too much power for what was needed ( make it easier for smaller statured people A.K.A. housewives to stop) , kind of like chyrslers power steering , it made it effortless to steer , well the Ford brakes would launch you on the steering wheel .