1955 w/ power brakes brake pedal pushes back then hard to push | Ford Thunderbird forum club group 1955-2005 models
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1955 w/ power brakes brake pedal pushes back then hard to push

  • Thread starter Thread starter JerryS
  • Start date Start date
JerryS
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Thunderbird Year
1955
When I step on the brake pedal , it goes down about an inch and pushes back then releases and the brakes work as tho no power assist

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sounds like a bad booster to me.
I agree, boosters are supposed to hold a "vacuum reserve" in case the engine shuts off while underway, so you can still get booster breaking for a short time....the symptoms described seem to indicate there is none.
 
I agree, boosters are supposed to hold a "vacuum reserve" in case the engine shuts off while underway, so you can still get booster breaking for a short time....the symptoms described seem to indicate there is none.
When the booster when out on my 64 I was driving on the freeway. Put the brakes on and a first all felt normal, then the pedal came back up and braking was almost non-existent. It was surprising how hard I had to push the pedal to get braking without the booster working. A rebuilt booster and all was back to normal.. except for a lighter wallet.
 
When the booster when out on my 64 I was driving on the freeway. Put the brakes on and a first all felt normal, then the pedal came back up and braking was almost non-existent. It was surprising how hard I had to push the pedal to get braking without the booster working. A rebuilt booster and all was back to normal.. except for a lighter wallet.
Exactly how the reserve is supposed to work...and yes unboosted brakes take a Herculean effort akin to power steering going out. Ugh.

My ultra rare, one-year-only 1963 Corvette brake booster was rebuilt by these guys, they really went the extra mile to correct previous bad repairs/restorations; several phone calls and 'back and forth' from them to make sure I was completely satisfied with what they were doing:

 
When I step on the brake pedal , it goes down about an inch and pushes back then releases and the brakes work as tho no power assist
Im have a slightly different issue not sure if its a brake booster issue. The brake pedal goes to the floor and slowly comes to a stop. Any ideas about a fix for this issue?
 
Im have a slightly different issue not sure if its a brake booster issue. The brake pedal goes to the floor and slowly comes to a stop. Any ideas about a fix for this issue?
Are you losing brake fluid? If so, you have a leak and should fix that first. If you are not losing fluid the most likely thing wrong is that the master cylinder is bad and the piston seals are leaking internally and not building pressure but just letting the fluid slip by. It might be that you have air in the system but my money is on the Master.
 
Are you losing brake fluid? If so, you have a leak and should fix that first. If you are not losing fluid the most likely thing wrong is that the master cylinder is bad and the piston seals are leaking internally and not building pressure but just letting the fluid slip by. It might be that you have air in the system but my money is on the Master.
Definitely not leaking brake fluids.
 
It's parked I'm definitely not driving it until the problem is resolved. Also the steering column is out so driving is complete out of the question.
 
Again check the brake bleed, even if the booster completely failed the system will revert to manual with a heavy pedal but competent braking ability, pedal should never go to the floor.
 
Again check the brake bleed, even if the booster completely failed the system will revert to manual with a heavy pedal but competent braking ability, pedal should never go to the floor.
I think it would be possible for the Master to be good but for the relay cylinder in the booster to be bad and have the same type of internal leak as the master and produce the same "pedal to the floor" failure.
 
Never heard of that, traditional boosters use engine vacuum to create a low pressure area on one side of the booster so air pressure on the other side helps push the M/C piston with a boost through a pushrod. The vacuum/air pressure side of the system is separate from the hydraulic side. If any part of the booster setup fails I don't see how that would affect the 'closed' hydraulic part of the system to have the pedal go to the floor.

But, hey, I'm trainable and admittedly, my booster experience is all GM and Mopar.
 
Never heard of that, traditional boosters use engine vacuum to create a low pressure area on one side of the booster so air pressure on the other side helps push the M/C piston with a boost through a pushrod. The vacuum/air pressure side of the system is separate from the hydraulic side. If any part of the booster setup fails I don't see how that would affect the 'closed' hydraulic part of the system to have the pedal go to the floor.

But, hey, I'm trainable and admittedly, my booster experience is all GM and Mopar.
In the 'Modern/Traditional" booster the brake pedal pushes directly against the booster valve which is integral with the booster diaphragm which has a plunger which then pushes against the Master. In that setup there is only one "cylinder" the master. The baby birds used a remote booster. Part of the remote assembly is a second "cylinder" which is very similar to a master cylinder. So in the Baby Birds there are two "cylinders" which can leak internally, the normal master cylinder and the second on that is part of the remote booster assembly. That complication is why no on uses a remote booster if they can possible fit a "traditional" booster/master set up into the space. I made a video explaining how the remote booster works, there are many places where things can go wrong.
 
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