3yr old float can never get brakes "in adjustment"

Discussion in 'Trucks [ Eighteen Wheelers ]' started by bowtieboy77, Apr 1, 2014.

  1. bowtieboy77

    bowtieboy77 Light Load Member

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    Aug 16, 2013
    Southern, Ontario
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    I will try to keep this fairly simple. We own a three year old witzco solid 3axle hyd rgn float. From the day it rolled into our yard it is near impossible to get brake stroke in the 2" range. It has full maxi's on front axle and service chambers on remaining two and all standard 30 size. The chambers are controlled by I believe its a sealco valve that when button is pulled applies supply pressure air from tank to service chambers for parking and the full maxis work as normal. The slacks are gunite self adjusters the style with the 7/16 hex. In my opinion I do not believe these are a good slack prefer the meritor with the 5/16 square drive. When slacks are tightened down so shoe touches drum and backed off 1/2 the brake stroke is about 2 1/4. If backed off 1/4 turn wheel is locked. I did notice when I adjust them just enough the wheel will turn I get 2" stroke but slack and rod are past 90 degrees. I am wondering if the rods were cut to long from factory but why can't I get them in stroke range? There is no cam play or clevis pin play and has done it since new. I am thinking about changing slacks to meritors and possibly installing full maxis on center axle aswell and plumbing in a multi function valve so it works like most trailers but I should still be able to get brake stroke in range using what is on it.. If the meritor slacks are gauged when installed as per instructions that might fix problem and again IMO they are a better slack. Any suggestions what could be wrong? I am licensed truck tech and I am adjusting them due to a annual safety that was performed and all drum and shoes measure well within limits. My other option is to change full chambers and all service chambers over to 30 long strokes but still doesnt solve why the brakes wont adj in range now?
     
    Last edited: Apr 1, 2014
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  3. jameslawton

    jameslawton Light Load Member

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    May 1, 2013
    Tulsa OK
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    I would check for loose wheel bearing drum might not be centered if loose
     
  4. Rooivalkpilot

    Rooivalkpilot Bobtail Member

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    Jan 16, 2014
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    15 degrees before 90 degrees with unapplied brakes, usually when brakes are applied the end position will be about 15 degrees past 90 degrees.
    this is what you want to get optimal force on the cam brake. remember self adjusting slack is what they say " self adjusting" so technically speaking the slacks should self adjust to the proper adjustment after a few brake applications. Make sure you connect the slack adjusters "self adjusting dial" into the correct position. You may find this "dial" has specified degrees on certain adjusters, so be sure it is the right adjusters for the application.
     
  5. Truck Smarter

    Truck Smarter Bobtail Member

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    Jun 26, 2014
    Dallas, Texas
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    Cut the rods shorter so you can get 90 degrees with the two inch stroke. Some trailer come that way-I have seen a few over the years. Lack of quality control at the factory? Changing the make of slack will not make any difference to the way the thing strokes.
     
  6. fortycalglock

    fortycalglock Road Train Member

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    Jun 25, 2011
    Tourist Town, FL
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    Stupid question, but are they long stroke brake chambers?
     
  7. bowtieboy77

    bowtieboy77 Light Load Member

    272
    80
    Aug 16, 2013
    Southern, Ontario
    0
    No as stated in post 30reg strokes which is 2' stroke limit. Again as stated in post I might convert to long strokes to give me 2.5" stroke limit.
     
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