1966 brake booster locking up on start up | Ford Thunderbird club group 1955-2005 T-Bird models

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1966 brake booster locking up on start up

  • Thread starter Thread starter Rom324
  • Start date Start date
Rom324

Rom324

Bronze Member
Reaction score
87
Thunderbird Year
1959
My 1966 T Bird brake booster locks the brakes and sucks the pedal down to the floor on start up. Pulled the master cylinder off and reset the spacer on the midland booster but same thing occurs. Any help?

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Rom324 said:
My 1966 T Bird brake booster locks the brakes and sucks the pedal down to the floor on start up. Pulled the master cylinder off and reset the spacer on the midland booster but same thing occurs. Any help?
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The brake booster worked fine before I unbolted the master cylinder to paint it. Will be checking the rod length to see if I pulled the rod out too far but I don’t think so. Everything bolted up fine
 
Rom324 said:
My 1966 T Bird brake booster locks the brakes and sucks the pedal down to the floor on start up. Pulled the master cylinder off and reset the spacer on the midland booster but same thing occurs. Any help?
Click to expand...
 
Rom324 said:
The brake booster worked fine before I unbolted the master cylinder to paint it. Will be checking the rod length to see if I pulled the rod out too far but I don’t think so. Everything bolted up fine
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I had to cut the vacuum line of the power booster and plug it off to get the car to move.
 
Rom324 said:
My 1966 T Bird brake booster locks the brakes and sucks the pedal down to the floor on start up. Pulled the master cylinder off and reset the spacer on the midland booster but same thing occurs. Any help?
Click to expand...

had the same nightmare happen, my mechanic did not do what he was doing, I ended up doing the job myself,
by adjusting the rod coming out of the booster until it was just right, took me several times and a lot of drinks, good luck!
 
didi said:
had the same nightmare happen, my mechanic did not do what he was doing, I ended up doing the job myself,
by adjusting the rod coming out of the booster until it was just right, took me several times and a lot of drinks, good luck!
Click to expand...

Thanks, I must’ve pulled the adjuster rod out somehow or got it misadjusted. All I did was take the spacer off and pull the master cylinder away to be able to paint the booster black and the master cylinder cast gray. Putting it back didn’t seem to be a problem until I started the car and the brake pedal got sucked to the floor. Had to cut the line to the manifold to move the car
 
Well Upon a closer look I must have pulled the adjuster rod out too far from the booster when I disengaged the master cylinder from the booster. It was stuck onto the master cylinder and unfortunately must’ve traveled past the diaphragm inside the booster. So like fingers on a clutch. The only relief here is that I will have to take the booster out and since this is a Midland band type booster I can separate the two halves. Hopefully I can push the rod back in behind the diaphragm so that it will be at the proper length. Other than that I would need to have it rebuilt. Bummer. The master cylinder seems to be OK and definitely stops the car when I disconnect the vacuum line from the booster. But it’s like stopping an elephant. Stay tuned
 
Rom324 said:
My 1966 T Bird brake booster locks the brakes and sucks the pedal down to the floor on start up. Pulled the master cylinder off and reset the spacer on the midland booster but same thing occurs. Any help?
Click to expand...
sounds like a bad or loose check valve on the booster
 
I us Booster Dewey in Portland Oregon He has doing my work for years. The best in the business
 
I had a friend who bought a booster on-line that was bad and the theory was it was sitting on the shelf too long. He ended up returning it and getting his original booster rebuilt by Booster Dewey and it worked perfectly. I think you should contact Booster Dewey and see what he says since I agree with old timer that he is the best.
 
Can the booster crap out while driving and you loose vacuum? Checked vacuum lines and not seeing a leak. But just stopped having power while getting off highway.
 
Bob611 said:
Can the booster crap out while driving and you loose vacuum? Checked vacuum lines and not seeing a leak. But just stopped having power while getting off highway.
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how about the check valve going into the booster?
 
Did you ever get this brake issue fixed? My 1966 that hasn’t really been driven in 10 years had the brakes (4) lock up while driving around the block.
 
Bills56tbird said:
Did you ever get this brake issue fixed? My 1966 that hasn’t really been driven in 10 years had the brakes (4) lock up while driving around the block.
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Well that's a shame not to be driving your '66. What are the symptoms exactly? I'm sure folks on this forum can help you to get it sorted.
 
All 4 brakes locked up on an exercise around the block. Engine started laboring and I was wondering why. Then I noticed the booster pin wasn’t in the center of the master cylinder. I plan on checking the vacuum check valve and taking apart the master today.
 

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If the MC fluid reservoir is dry, it had to go somewhere. If not on the ground, then the fluid may have gone from the MC into the booster in which case it's inoperable and likely toast.
 
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