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Brake system questions

Discussion in 'Tractor/Loader/Backhoes' started by DO-MOR FAN, Mar 6, 2012.

  1. DO-MOR FAN

    DO-MOR FAN Member

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    This is a picture of the brake system off my loader/backhoe. Can anyone tell me how this works? As usual the pedal plunges into a master cylinder that a small steel reservoir is bolted inline. On the far end of this reservoir is the one brake line that runs up though park brake valve then splits to all four wheels. What I don’t understand is why there is a hydraulic line coming out of the primary hydraulic pump into the master cylinder then out to the steering system. Is this some kind of charged/hydraulic pressurized brake system? I took off the cap on the reservoir and it was dry in there. also pulled some bleeders at the wheels and they were dry too. The pedal currently freely goes to the floor. What’s a good way to bleed this system? any help is greatly appreciated.

    master cylinder2.jpg
     
  2. ijoker

    ijoker Well-Known Member

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    You didn't say what kind of machine you have but it sounds to me like you have a hydralic system for the brakes and the steering. How does the steering work? Or does it? The reservoir i am not sure about. If you in fact have a line coming off of your main hydralic pump and that reservoir is your fill point, then it may need some fluid. I would suggest you find out if the hydralic pump is running something other than the brakes and the steering. If that is the case, and everthing else is working good, then i would say there is some other problem. If the brakes and the steering are the only things driven by the hydralic pump though, maybe all it needs is some fluid. :) Then you would bleed the brakes like you would on any other vehicle. Without any information on the machine, that is the best 2 cents i can offer. There are those on this forum with more knowledge than me. :notworthy In any case it sounds like you have a simple problem. Good luck, Joe
     
  3. DO-MOR FAN

    DO-MOR FAN Member

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    Thanks Joe. It is a late 70s Do Mor 707. It a component tractor made in Michigan. This tractor has all wheel steering. When its running it does have steering. The brake unit is upline to the steering so I am isolating the issue to this brake unit. The hydraulic line must go to this brake unit maybe add pressure similar to what a booster pump does in the typ car....?? i was trying to bleed but with very little pressure. I wonder if i can only bleed the system if the tractor is running or maybe the seals inside this funky master cylinder are just shot. thanks for the response.
     
  4. alrman

    alrman Senior Member

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    I would like to see some pics of this "Do Mor" - never heard of one.
    Post them in the "Pictures of your backhoe" thread :)
     
  5. willie59

    willie59 Super Moderator

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    I can't say for certain, but Parking Brake valve you describe sounds like a Mico brake valve, should not be used for parking. As for the master cylinder arrangement, with hoses coming from hyd pump going to steering circuit, that sounds like a hydro boost for brake system, Galion cranes used to use a hydo boost system similar to that on their brake master cylinders.
     
  6. ijoker

    ijoker Well-Known Member

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    Hmmmmmmmmmmm..........Hydroboost. Beyond me! :beatsme If it was in front of me i could probably figure it out.
     
  7. ijoker

    ijoker Well-Known Member

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    If i had known there was something out there called a do mor, i would have got it from your forum name. :pointhead Anyway..... Sounds like you need a manual my freind. If the brakes lines are completely empty, then it is going to take a lot of bleeding. Especially with that parking brake before the wheel lines. As for doing it with the engine running or not....... i would say try it. I don't think it can hurt.
     
  8. bowen

    bowen Senior Member

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  9. domorguy

    domorguy New Member

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    i dont think so
     
  10. HATCHEQUIP

    HATCHEQUIP Senior Member

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    Like Willie said hydraboost and you can start bleeding brakes without it running turn the mico brake valve so that the fluid can go thru it fill reservoir and open all the bleeders making sure their clear and not stopped up cut them off when they start dripping might take awhile keep master cyl. full if they want start dripping close them and start pumping and cranking lines while someone holds pedal down when you start feeling some pedal crank it and bleed it some more at that time you'll have power to the brakes. That mico brake lock works by applying the brakes and while holding the pedal down you flip the valve and it blocks the fluid so the brakes stay on but don't don't trust them they will will leak off
     
  11. Tinkerer

    Tinkerer Senior Member

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  12. DMiller

    DMiller Senior Member

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    Looks like some of the machines custom built for aviation snow removal here, is one similar but Ford at Chesterfield Airport for tight areas snow removal.
     
  13. HATCHEQUIP

    HATCHEQUIP Senior Member

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    didn't realize post was old:beatsme