replacing brake chamber - issue

Discussion in 'Trucks [ Eighteen Wheelers ]' started by rollin coal, Oct 10, 2016.

  1. AModelCat

    AModelCat Road Train Member

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    The slacks typically adjust to maintain a 90 degree angle between pushrod and slack centerline. Cut too long and it'll adjust too tight. Cut too short and it'll adjust loose (if that explanation makes sense).
     
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  3. rollin coal

    rollin coal Road Train Member

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    No it needed more threads cut. Both brake chambers were un-caged with the rod sticking all the way out. The one that came off the truck measured 2-1/4" between the brake chamber and the face of the jam nut up against the clevis. The closest I could thread that jam nut on the rod to the new brake chamber was 3". I had to cut more threads on it. I didn't know that some manufacturers cut the threads in much closer to the chamber than others. First time I have ever swapped one out. Several people suggested to me running a die up the rod or taking it back and getting one with more threads. I just wanted to be sure I wasn't wrong running a die up it.
     
  4. Ezrider_48501

    Ezrider_48501 Road Train Member

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    just throw on a half can and a new service break diaphragm. way faster easier repair just as good. only time i ever replace the whole break can is when the front starts getting too rusty.
     
  5. rollin coal

    rollin coal Road Train Member

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    Just seems half assed that way. The whole assembly is cheap. Might as well toss everything and replace with new. They are all 6 years old and this is the first one to fail.
     
  6. AModelCat

    AModelCat Road Train Member

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    Biggest thing I ran into back when I worked on trucks was those clevis pins always being seized solid in the clevis. Of course the company was too cheap to buy new ones so I'd waste an hour trying to save a $12 clevis. :dontknow:
     
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  7. Ezrider_48501

    Ezrider_48501 Road Train Member

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    try it once and you will probably be converted.....lol

    if you put a half can and a new service break diaphragm your replacing everything that wears out.

    if your leak is just on the service break side its literally 10 mins and 5 bucks to just slap a new diaphragm in. don't even need to disconnect the hoses. cage it and pop the band clap

    to do a half can you dont have to mess with cutting the rod to length frozen clevis pins ect. just cage it take the hoses of pop the band clap off.
     
  8. AModelCat

    AModelCat Road Train Member

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    I usually just chock the wheels, crawl under with vice grips and clamp the pushrod from retracting, then release the brakes and install the caging bolt. That way you don't have to waste time with a wrench. Just spin the caging nut on by hand. Then apply brakes, remove the hoses and pop the park chamber off. Install new caged chamber and reverse steps. If everything goes well, 20 mins max.
     
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  9. pup

    pup Light Load Member

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    If the maxi spring was broken it may not be fully extending the rod out of the can. I usually charge the service side of the can to be certain the rod is fully extended.
     
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  10. BoxCarKidd

    BoxCarKidd Road Train Member

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    And there are two different lengths on the center sections on 30/30's.
     
  11. rollin coal

    rollin coal Road Train Member

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    It looks the same as the push rod on the other side when the brakes are depressed and released. It measured 1.75" of travel and right at 90* when depressed. That should be everything A-OK right?
     
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