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Brake Problems...

Discussion in 'Early CJ5 and CJ6 Tech' started by 53Flattie, Oct 19, 2004.

  1. Oct 19, 2004
    53Flattie

    53Flattie Intigator

    Easley, SC
    Joined:
    Sep 23, 2002
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    842
    I'm running a remanufactured MC. It has worked fine for months, and I know that other early CJ owners are using it. It's set up for drum/drum.

    A few weeks ago, I noticed that the driver's front wheel cylinder was not releasing. The brake lights would stay on, even when you took your foot off the brake pedal. When I got home, I'd have to open the bleeder screw and release the pressure.

    I assumed the wheel cylinder was gummed up and wouldn't release, so I ordered up both front wheel cylinders and new pads. I installed everthing and it worked great... for about a week.

    Last night I drove the Jeep a little and noticed that when I put her back in the garage, the brake lights stayed on. Sure enough, when I opened the bleeder screw on the drivers side front, fluid came pouring out.

    What could be casuing this? All the springs holding the pads on had plenty of tension, so those aren't the problem. As I said, the wheel cylinders are brand new. The MC is set up for drums, so the proportioning valves should be 10 pounders. Is it possible that I could have the brakes adjusted out too far? There is next to no play in the pedal. Pretty much as soon as you step on them, you're stopping.

    Any thoughts?
     
  2. Oct 19, 2004
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    Sep 20, 2002
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    How close are the lines to heat?
    When you redid the lines did you make "pressure" loops.........
     
  3. Oct 19, 2004
    linckeil

    linckeil Member

    Danbury CT
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    Aug 19, 2004
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    492
    Are these manual or power brakes? is it a dual or single reservior master cylinder? there is rod which pushes on the master cylinder when you apply pressure to the brake pedal. The rod should have an adjustable length. If it is adjusted too far out, it will apply pressure on the master cylinder even if your foot is off the brake pedal. I would check this rod and back it off 3 turns, see what happens, and go from there.....
     
  4. Oct 19, 2004
    53Flattie

    53Flattie Intigator

    Easley, SC
    Joined:
    Sep 23, 2002
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    Billy - All lines are stock (well, I replaced a few, but I bent them just like the stockers, and the follow the stock routing). What are these "pressure loops" that you speak of?

    Linckeil - Good point here. I had to modify the push rod slightly, and it doesn't have adjustment. But, they have worked fine for several months. I'm not sure why this would become a problem now...

    Edit - Manual brakes, dual chamber MC
     
  5. Oct 19, 2004
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    Ever notice a line will have an extra loop in it for no reason or a bend.......

    They are there to allow for fluid expansion.........

    Just thinking outloud
     
  6. Oct 19, 2004
    53Flattie

    53Flattie Intigator

    Easley, SC
    Joined:
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    Hmm. I always thought they were there to allow flexing between the body and frame (b/c most MC are mounted to the firewall and the lines run to a rigid mount on the frame).

    Learn something new every day, huh?!!!
     
  7. Oct 19, 2004
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    That too......
    Got to give that fluid some place to go.........
     
  8. Oct 19, 2004
    Russell

    Russell New Member

    Greensboro, NC
    Joined:
    Sep 15, 2003
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    35
    Since the system is free of air (at least I think it is free of air ...the bleeding of the brakes) I would think the lines (and the whole system) is 100% full of brake fluid. It is a sealed system of brake fluid that is compressed by the master cylinder to actuate the wheel cylinders.

    I am not an expert but I don't think air is in the line.
     
  9. Oct 19, 2004
    DanStew

    DanStew Preowned Merkin salesman Staff Member

    Lexington, South...
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    Sep 22, 2002
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    4,585
    You know maybe it is the pressure switch for the lights. does it happen to both wheel cylinders?? Maybe the pressure switch is gummed up. I just got rid of the "juice brakes" and made a bracekt and used a CJ7 switch on the column.
     
  10. Oct 20, 2004
    53Flattie

    53Flattie Intigator

    Easley, SC
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    Sep 23, 2002
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    Thanks Dan!

    Unfortunately, it's not just the switch. I can tell that the driver's front isn't releasing b/c I don't have to hold the brakes at a stop light to keep from rolling! :D
     
  11. Oct 20, 2004
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Did you modify anything, like where the lines are plumbed from? You've already determined that one wheel cylinder/line has residual pressure so where does that line come from? How about the rubber hose, maybe it's plugged and not releasing pressure?
     
  12. Oct 20, 2004
    53Flattie

    53Flattie Intigator

    Easley, SC
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    I didn't modify anything, but I did change out most of the parts - including the rubber lines. They were not used, but had been sitting on a shelf for a while, and it's possible that they are clogged with something. I'll have to take that one off and see if it's blocked.

    Good idea Glenn. Thanks!!! ;)
     
  13. Oct 20, 2004
    Russell

    Russell New Member

    Greensboro, NC
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    I had lots of problems with a VW Beetle's brakes once and the culprit ended up being the rubber brake lines. They were clogged-up. Could be one of your rubber brake lines is allowing flow in one direction but pluggining up on the opposite direction (pressure release).
     
  14. Oct 20, 2004
    TheBeav1955

    TheBeav1955 Member

    Wyoming, Mi
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    I've know of the rubber lines seperating on the inside and then a flap of the seperated part will act lilke a valve and not allow the fluid to flow back into the master when the pedal is released. That would explain the wheel being hung, but it would not explain the lights staying on. If you have drums all the way around there is not a prop valve in the system only the residual pressure valves in the M/C that help keep a very small pressure in the lines 10lbs IIRC. Isn't the switch screwed to the bottom of the master? The one I took out of mine when I upgraded to discs this spring was there. Might be 2 problems you are chasing. Just a thought.
     
  15. Oct 20, 2004
    maxx

    maxx Banned

    Menlo Park, Ca
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    Apr 22, 2003
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    171
    what about the residual check valve in the master cylinder? maybe its sticking and not allowing fluid to return?
     
  16. Oct 20, 2004
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    Dec 22, 2002
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    Just out of curiosity, do you have both the front brake line switch, and the rear brake line switch installed?? on mine, the switch is only on the back. If yours is on the rear line, and its sticking its not the front brakes. If your fronts are sticking too, then like Linckeil said, I'd check the push rod. who knows. Maybe something shifted causing it to bind up??
     
  17. Oct 20, 2004
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Weird part is only left side sticks.
     
  18. Oct 20, 2004
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    little brass T- fitting up front that diverts to the left and right??
     
  19. Oct 20, 2004
    53Flattie

    53Flattie Intigator

    Easley, SC
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    I *have* a pressure switch up front and in the back, but only the back is hooked up. Good point Brian (Hurt) - I didn't think of that...

    I will swap out the brake hose with another that I have and see if that corrects the sticking cylinder. If the lights continue to stay on - I'll then tackle that problem. I think you might be right Brian (Smith) that there are two different problems here...
     
  20. Oct 20, 2004
    53Flattie

    53Flattie Intigator

    Easley, SC
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    Negative - Dual chamber MC with seperate ports for front and rear.
     
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