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Technical 1940 ford brakes help pls

Discussion in 'The Hokey Ass Message Board' started by Elijah Lester, Sep 6, 2018.

  1. Elijah Lester
    Joined: Sep 6, 2018
    Posts: 10

    Elijah Lester
    Member

    I'm trying to bleed the brake lines on this 40 ford, the pedal isnt getting resistance and no matter how many times I bleed the cylinders and fill the master im still getting bubbles. No leaks in the lines at all. I'm at the point of trying to adjust the shoes so they just slightly rub the drum at 25% pedal. But can't get a good pedal pressure. Any suggestions?
     
  2. Adjust all 4 shoes so they drag first. If you haven't adjusted early Ford brake shoes before, study up on the right way to do it before you try, they ain't Bendix brakes by a long shot. Make sure your pedal geometry is correct and the if you have an adjustable rod between pedal and piston, ensure it retracts far enough to vent the line back into the reservoir.
    Once all that is right, try again.
     
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  3. Baumi
    Joined: Jan 28, 2003
    Posts: 2,200

    Baumi
    ALLIANCE MEMBER

    Maybe your mc is to small. I had the Same problem on my 34 with 40 brakes. Never had a good pedal and almost no braking power. Switched from a 1" to a 1 1/8" mc, problem solved.
    But first adjust the brake shoes properly, as in as close to the drum as possible!
     
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  4. alchemy
    Joined: Sep 27, 2002
    Posts: 14,580

    alchemy
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    I also concur, it is very important to adjust the shoes to "really close" before doing any brake bleeding with this type of brakes. You can readjust them later.

    Just for kicks, pull the drum off the front brake and make sure you aren't leaking fluid inside the unit (past the wheel cylinder cups). This is common with the new production cylinders if the brakes aren't adjusted before putting fluid in the system.
     
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  5. 46Chief
    Joined: Jan 2, 2008
    Posts: 157

    46Chief
    Member

    Had a similar problem, the reproduction F1 M/C had the plunger seal backwards from the factory. Should have taken apart to inspect, but flushed it with alcohol as a short cut instead. Also get a power bleeder, it will be your best friend.
     
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  6. Elijah Lester
    Joined: Sep 6, 2018
    Posts: 10

    Elijah Lester
    Member

    Ok... Adjusted all drums til barely rubbing. Still squishy pedal, so bought a plug for the brass fitting where the lines split between front and back brakes. Plugged off each side one at a time and had great pedal resistance in back. Reconnected back line and plugged the front line and got good pedal as well. Connect both sides and bled the lines and now I have a squishy pedal again and am getting alot of little bubbles in the line on front. Checked connections no leaks. So when I'm only pushing fluid to the back drums I have lots of pedal resistance. When pushing only to the front everything works fine. When both lines are connected it goes all the way to the floor....??? What does this mean???
     
  7. adam401
    Joined: Dec 27, 2007
    Posts: 1,802

    adam401
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    Maybe I missed it in all the posts and I'm sure you know this but did you bench bleed the master? A single reservoir master can have trapped air as easily as a dual res master.
     
  8. Elijah Lester
    Joined: Sep 6, 2018
    Posts: 10

    Elijah Lester
    Member

    Yeah, I did that pretty much first thing, would it effect it with only one line hooked up though? Cause it was functioning perfectly when it was just the front drums hooked up, and when it was just the back drums. The problem arises when both lines are hooked up to the master cylinder
     
  9. adam401
    Joined: Dec 27, 2007
    Posts: 1,802

    adam401
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    Just read your post. I don't know the answer to that.
     
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  10. The 39 guy
    Joined: Nov 5, 2010
    Posts: 2,672

    The 39 guy
    Member

    [​IMG]
    Looking at this cross section of a MC makes me think you may have some bad seals or perhaps need to adjust the pedal linkage as it may be affecting the pedal rod which may affect the rubber piston cup location. Just thinking you may be loosing fluid to the bypass port. Just guessing. I am no expert but I am interesting learning how you solve this problem.
     
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  11. You have the curse of the no-intro post upon you. Once you do that everything will fall into place.

    Is this a stock '40 Ford brake system or something else?
     
  12. @Elijah Lester "So when I'm only pushing fluid to the back drums I have lots of pedal resistance. When pushing only to the front everything works fine. When both lines are connected it goes all the way to the floor....??? What does this mean???"
    This means you don't have enough fluid volume in the master cylinder to take up all the slack in all 4 wheel assemblies. If this is a stock system, and half of it "works fine" then you are trying to move the shoes farther than the system is capable of, probably because at least one of the sets of shoes is not adjusted properly. Go back and read how to adjust early Ford brake shoes again, adjust them all just like the procedure describes, and try again.
     
    BJR likes this.
  13. BJR
    Joined: Mar 11, 2005
    Posts: 5,960

    BJR
    Member

    X2
     

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