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  #1  
Old 10-24-2017, 06:00 PM
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Update: 76 280C no brake issue....

Well, I changed the master cylinder which was old and leaking. I took the car for a drive and everything was fine, after about half an hour and 10 miles away from home, the pedal went all the way to the floor again.
I drove home very gingerly and after a while the pedal rose again.
Can we agree that I need a Brake Booster or do you guys think I have another issue.
Where would I find the Brake Booster Hose? I have searched and it seems that no one has this part. Would it be a stealership only item?

Thanks in advance.

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1976 280C
SLOWER DRIVERS KEEP TO THE RIGHT.
DRIVE RIGHT PASS LEFT

Last edited by Tomas7; 10-24-2017 at 07:11 PM.
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Old 10-24-2017, 07:23 PM
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If your brake booster fails, the pedal gets hard, not soft (lack of power assist). If the pedal is going to the floor you could have one or more problems:

- MC issues
- Air in the lines (you did bleed the brakes properly?)
- Failing rubber brake lines
- Leak in the system
- Old fluid (full of moisture)
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  #3  
Old 10-24-2017, 08:59 PM
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T:

With the car on a level surface, engine off, park brake off, neutral, can you roll the car easily by hand?
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Old 10-25-2017, 10:54 AM
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Quote:
Originally Posted by Frank Reiner View Post
T:

With the car on a level surface, engine off, park brake off, neutral, can you roll the car easily by hand?
No, it is harder to push.
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1976 280C
SLOWER DRIVERS KEEP TO THE RIGHT.
DRIVE RIGHT PASS LEFT
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  #5  
Old 10-25-2017, 11:40 AM
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Quote:
Originally Posted by Tomas7 View Post
No, it is harder to push.
T:

Consider the probability of one or more stuck pistons in the brake calipers. If the brake pad is dragging on the rotor, the temperature of the pad & piston will rise significantly, to the point that water entrained in the brake fluid in the caliper changes from liquid to vapor. At that point pressure in the system compresses the water vapor, instead of acting on incompressible liquid. Et voila, pedal on floor.
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Old 10-27-2017, 10:47 AM
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Quote:
Originally Posted by Frank Reiner View Post
T:

Consider the probability of one or more stuck pistons in the brake calipers. If the brake pad is dragging on the rotor, the temperature of the pad & piston will rise significantly, to the point that water entrained in the brake fluid in the caliper changes from liquid to vapor. At that point pressure in the system compresses the water vapor, instead of acting on incompressible liquid. Et voila, pedal on floor.
Yes sir, you were right.
I am ordering rebuild kits for all four corners, pads for all four corners and rotors for all four corners. The hoses were new about three years ago before the car went into hibernation.

Thank you very much.

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1976 280C
SLOWER DRIVERS KEEP TO THE RIGHT.
DRIVE RIGHT PASS LEFT
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