Brakes Are Too Hard

Discussion in 'Fox 5.0 Mustang Tech' started by stykthyn, Jul 29, 2013.


  1. stykthyn

    stykthyn Commander of the snuggie cultists

    Joined:
    Jul 6, 2006
    Messages:
    8,115
    Likes Received:
    591
    Trophy Points:
    163
    Location:
    gainesville
    ok heres the setup. 99 calipers up front and drums in the back. 95 master cylinder and 3-2 conversion. when I first installed it everything was gravy. Car then had an engine fire and sat for a while. Everything is now in running condition again but my brake pedal truly feels like I have to stand on it and jump up and down to get it to stop. Fluid level is good and there is no air in the system. Could the heat from the fire have killed my brake booster? Its the only thing I can think of that would cause this issue.
     
    #1
  2. mikestang63

    mikestang63 Mustang Master

    Joined:
    Aug 28, 2012
    Messages:
    4,036
    Showcase:
    20
    Albums:
    1
    Likes Received:
    1,144
    Trophy Points:
    154
    Location:
    In the garage
    that was my guess or it burned up the piston in the MC?
     
    #2
  3. stykthyn

    stykthyn Commander of the snuggie cultists

    Joined:
    Jul 6, 2006
    Messages:
    8,115
    Likes Received:
    591
    Trophy Points:
    163
    Location:
    gainesville
    Is the piston was bad the pedal would fall straight to the floor
     
    #3
  4. reldla1996

    reldla1996 Member

    Joined:
    May 5, 2011
    Messages:
    356
    Showcase:
    5
    Albums:
    1
    Likes Received:
    22
    Trophy Points:
    19
    Location:
    Dayton, Ohio
    Sounds like the booster. If you put your foot on the brake, and start the car, does the brake pedal move?
     
    #4
  5. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

    Joined:
    Mar 10, 2000
    Messages:
    21,807
    Likes Received:
    394
    Trophy Points:
    134
    Location:
    Dublin GA
    Power brake booster test:
    1.) Check engine vacuum you should have 14"-18" of vacuum at 625-750 RPM, 18"-21" vacuum at 1000 RPM.
    2.) Vacuum checks good, start car and run engine up to 1000 RPM for 30 seconds.
    3.) Cut off the engine and then press the brake pedal 3 times. It should get harder to press and travel less each time you press it. If it doesn't, then the brake booster is suspect.
     
    #5
  6. stykthyn

    stykthyn Commander of the snuggie cultists

    Joined:
    Jul 6, 2006
    Messages:
    8,115
    Likes Received:
    591
    Trophy Points:
    163
    Location:
    gainesville
    pedal movement is normal, just takes fred flinstone level effort to stop
    will do. need to pick up another vacuum gauge and will report back. There is a slight idle fluctuation that I strongly suspect is a vacuum leak related to the brake booster.
     
    #6
  7. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

    Joined:
    Feb 19, 2001
    Messages:
    21,689
    Likes Received:
    318
    Trophy Points:
    124
    Location:
    Massachusetts
    My guess is rubber diaphragm in booster is toast.
     
    #7

Share This Page