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no brakes on '76 FJ40

Discussion in '40- & 55-Series Tech' started by buchhla, Mar 12, 2004.

  1. buchhla

    buchhla

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    Hi, looking for some suggestions on a brake problem. I am thinking of comtinueing my friends project fj40, and from what I can tell, the only mechinical issue I have is no brake. Non, whatsoever. I looks like there were disc installed in the rear, and it has a new master cylindar as well. I am thinking either bad lines somewhere (no visable leaking), bad booster, or maybe just a botched install job on either the rear discs or the master cylindar replacement. Any idea on a reasonable attack plan?

    I can seem to build up some pressure by pumping the brakes, but if I press harder, the pedal goes to the floor. It also does seem to build pressure better when the engine is running, so I think the brake booster is somewhat functional. We have tried bleeding the lines to all the dics and no difference.

    I would really love to get her moving again, well I guess I can do that, but stopping short of a tree or ditch would be desirable!

    Regards...
     
  2. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Welcome.

    I would verify that you do not have any air trapped in the system by flushing out all fluid with new fluid, and bleeding the whole system. I would start with one end, either the front or the rear, and figure out what is going on.

    When you are bleeding the system, are you getting a good stream of fluid?

    What condition are the calipers, hoses and brake lines?

    Good luck!

    -Steve
     
  3. nocents

    nocents SILVER Star

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    Think about how the system is supposed to work and begin trouble shooting...Master cylinder delivers fluid at a pressure via the brake lines to the brake cylinders, cylinders expand under pressure for brakes to work.

    Does master cylinder do it job?
    Are lines clear?
    Are brake cylinders free to move?

    If none of the brake work start at the master cylinder and work to brakes

    nocents
     
  4. dd113

    dd113

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    Bleed the MC then plug it. Same bleeder plugs fit the MC. If you have a hard pedal with the MC plugged it is good. DO the RR one side at a time. Then do the FT. Then do it again. Get a lot of fluid out of both ends.If it is still weak block off the Back side port on the MC with a bleeder and see how the fronts work. Good way to isolate the issue. There are proportioning valve issues but they should not keep you from having a good pedal.
     
  5. Romer

    Romer fatherofdaughterofromer Moderator

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    Are you sure the Master Cyl is new? this can happen when the seals wear out in the Master? Do what Steve and Dave said and bleed your brakes. Air in the system would do this as weel. While your at it, you might as well adjust your brakes.
     
  6. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    4 wheel disc set up....what is there to *adjust*, unless something is not installed correctly on the rear swap...
     
  7. Romer

    Romer fatherofdaughterofromer Moderator

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    Missed the 4 wheel Disk Brakes when I was tying my response. I was thinking about just replacing my master cyl, bleeding the system and adjusting the rears on my 77.

    Whats the payback of replacing the rear drums with discs?