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Who knows air brakes?

Discussion in 'The Lounge' started by BigOrange90Jimmy, Feb 10, 2007.

  1. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

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    I'm posting this here cause we don't really have a section for it.

    I've got an issue with a truck here on Bladenboro Fire, and the mechanic(s) that have worked on it previously apparently suck. It's been "repaired" multiple times, but the root problem is still showing.

    I'm having to drain water out of - what I guess is the accessory tank - almost daily. I have water in the parking brake actuator, and the air horns. Of the three air tanks on the truck, only one tank ever has water in it.

    Today when I was running a call, I almost had to call for support. The whole time I was en route, I could smell brakes burning. When I arrived on scene and got it parked, smoke engulfed the cab. It was rolling heavy from both front wheels.

    Repairs - air dryer has been replaced, front and rear shoes also. There is an air leak from the front of the truck, but I'm not about to mess with it (there's a lot of liability when doing repairs to an emergency vehicle). I know these guys aren't getting the root problem, and I'm pretty sure it involves this air leak, and possibly the air dryer.

    What can you guys tell me.
     
  2. skyyk5

    skyyk5 1/2 ton status

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    Sounds like the dryer alright! Can you hear were the leak is coming from?
     
  3. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

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    Yes. It's somewhere right behind the front bumper.

    When the tank/lines have water in them, the - I guess it's a blow-off valve - doesn't give it's usual release of air. It quickly opens and shuts three times, as opposed to it's normal and steady release.

    I just can't understand why it's just this tank. Well, on second thought, that tank is mounted lower, so it's only right that water would be in the lowest spot, so scratch my non-understanding babble. HAHA!
     
  4. skyyk5

    skyyk5 1/2 ton status

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    It's been years since I worked on air brakes. But the mechanic for my Fathers work trucks might stop by tomorrow. If he does I'll ask him.
     
  5. wasted wages

    wasted wages 3/4 ton status

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    does the air drier "pop off" when the pressure builds up?

    every time the compressor " unloads " the air drier should pop off also.

    I think there is a 1/4 inch line that runs from the unloader on the air compressor to the dump valve on the air drier.

    It's been several years since I messed with air brakes....
     
  6. mxfireman

    mxfireman 1/2 ton status

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    Air tanks are supposed to be drained daily on the older style air tanks. I have a newer engine and I still drain mine daily. It is a good thing that the water is only in one tank, which is called the "wet" tank.

    When were the brakes replaced? When brakes are new they will smell and smoke the first times they are used.

    Have you taken time to measure the throw on the brakes? My department requires that manual slack adjusters be kept at or below 1 1/2". On automatic slack adjusters my department have to be kept at 1 3/4".

    Can you post up some more info on what type of brake adjusters you have? Also how new/old is the engine. If the brakes and the slack adjusters are within normal limits, maybee you need to lay off the skinny pedal a little bit and use some gears to slow you down?
     
  7. Corey 78K5

    Corey 78K5 1 ton status

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    Sounds like a bad air dryer or you have another air tank that needs to be drained.

    I will assume that you were not riding the brakes........So first thing I would check is to make sure your shoes are matched with your drums otherwise you will burn them quick like. Also make sure you don't have a slack adjuster or brake cam sticking.

    Can you be more specific on the location. Build up some air or hook up an air hose to the air tank and simply locate the air leak.
    Last but not least have you checked out the compressor?
     
  8. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    Air dryer isn't purging and/or dessicant is saturated. If it's an AD9 dryer, they're cake to fix. I've also had head gaskets for the compressor make strange things happen. Remove the air outlet line from the compressor and put a piece of paper in front of it with the engine running and the compressor loaded and see if it's shooting anything other than air out...a little oil splatter (VERY LITTLE) is normal. Give me a shout if you need more help, I work in a shop for Class 8 trucks and we do work on some fire engines.

    The other possible air leaks, you could have a bad brake can, ABS valve, quick release...lots of possible things. Try to find where the leak is coming from and take a pic or describe to me

    Good practice...drain your tanks at the END of the day EVERY DAY. Water gets into places and plays hell with things, corroding and the like. Make it something you do EVERY DAY.
     
  9. TSGB

    TSGB 1 ton status

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    Pad.
     
  10. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

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    I know nothing about what kind of adjusters are on it. I just know that they don't work...HAHA! The engine is a '92 E-One Pumper. We, as volunteers, aren't allowed to perform maintenance on the engines (that whole liability issue). The front brakes on the truck are just dragging. When you release the park brake, the truck won't roll at idle like it used to.

    I'll try to get you a pic today.

    Brakes were replaced a year ago on the front. The rears were replaced in the first part of December.
     
  11. mxfireman

    mxfireman 1/2 ton status

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