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Hi, guys- I'm looking at a '68 galaxie that is pretty clean, but.... the brakes system (discs front) has been recently redone, with a new master cylinder and booster. When you touch the pedal, there is a lot of resistance, then it suddenly goes normal. I know, weird. Try it when you're not familiar with the car!!! It is not possible to lightly apply the brakes, you have to push hard to get the pedal through its fist inch or so of travel, then stop pushing hard and it is normal. If it is a major repair, I'm hesitating over buying the car. Has anyone got any ideas? Maybe linkage adjustment between booster and master cylinder?
Appreciate any help.

Plus- the car is supposed to be a GT. How do you tell if it is? And what advantage is there to being a GT? Thanks!
 

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the brakes system (discs front) has been recently redone, with a new master cylinder and booster. When you touch the pedal, there is a lot of resistance, then it suddenly goes normal. I know, weird. Try it when you're not familiar with the car!!! It is not possible to lightly apply the brakes, you have to push hard to get the pedal through its fist inch or so of travel, then stop pushing hard and it is normal. If it is a major repair, I'm hesitating over buying the car. Has anyone got any ideas? Maybe linkage adjustment between booster and master cylinder?
Does it have OEM front discs or a conversion?

Troubleshooting Guide-

Test Power Brake Booster

If the pedal feels "hard" while the engine is running, the booster isn't operating correctly. If you suspect the booster is defective, do not attempt to disassemble or repair the power booster. Doing so is unsafe and will void your warranty.

Test 1

  1. With the engine off, pump the brake pedal to remove any residual vacuum in the booster.
  2. Hold pressure on the pedal while you start the engine. When the engine starts, the pedal should drop about a 1/4", this indicates that the booster is working properly.
Test 2

  1. Run the engine a couple of minutes.
  2. Turn the engine off and press the pedal several times slowly. The first pump should be fairly low. The second and third should become slightly firmer. This indicates an airtight booster.
Test 3

  1. Start the engine and press the brake pedal, then stop the engine with the pedal still pressed. If the pedal does not drop after holding the pressure on the pedal for 30 seconds, the booster is airtight.
Inspect the Check Valve

  1. Disconnect the vacuum hose where it connects to the intake manifold. Do not disconnect the vacuum line from the booster. Air should not flow when pressure is applied, but should flow when suction is applied. If air flows in both directions or there is no air flow, the valve needs to be replaced.
Verify Enough Vacuum

  1. Check the operating vacuum pressure when the engine is at normal operating temperature. There should be a minimum of 18 in. of vacuum. Vacuum may be increased by properly tuning the engine, checking for vacuum leaks and blockages in vacuum lines.

SOURCE- CCP Brakes


The above chart will get you started. The Shop Manual will have a more detailed diagnostic sequence if the brakes are factory.

Plus- the car is supposed to be a GT. How do you tell if it is? And what advantage is there to being a GT?

Thanks!
Post the VIN and Body Code.
 

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is the booster on a pedistal mount or flush mounted on fire wall....

anyway..i ran into the same problem when i upgraded to power brakes
with aftermarket booster and pedistal setup....

if you look where i put a Red X in picture..
lever was real tight against rubber booth..
under booth is a pvc tube and and booster valve is in center of that..
thats where lever eyelet connects to booster....

problem was that angle of lever was to steep and when applying brake
pvc tube was being pushed first until angle lessen and pressure got applyed to booster valve....

the way i corrected that was...
put a slight notch in lever at X and spacer between pedistal and booster in lower picture...
that way pressure got applyed immediate to valve when pressing brake pedal...

i got booster and pedistal setup from two diffrent sources..
they where not a matched pair and thats was the problem from get go...

hope this was helpful and made some sense....:D



 

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Very good advice Lars, I was leaning towards the booster in his first sentence and didn't see anything else in the paragraph that would make me think less.

Now for his GT question. You're going to have to come up with the VIN number first, then tell us if the engine is original and trans is original to the car, only then will it matter if it's a GT or a plane jayne...
 

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I would assume the seller meant XL, because there was no '68 Galaxie GT. As it has been mentioned the info in the VIN and Data plate will show the body codes and what model it was. You can search the net and find all the different info so you can decode it when you look at the car.
 
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